1. BONES
(Use articulated skeletons & bone sets)
Extra:(Ellipsoid joint: Condylar joint)
Bicipital Aponeurosis : Will cause biceps to flex when the forearm supinates
Volar palmar
(Pertaining to the palm)
1.1. Identify the parts of the upper (proximal) radius.
Radial tuberosity, head and neck of radius
1.2.Identify the bone that articulate with the radial head .
Radial notch on ulnar, round capitulum of the humerus
1.2.1.Identify the ligament that surrounds the radial head.
Annular ligament retain radial head along with radial notch of ulnar
1.2.1.1. What is its shape and why is its lower margin free?
Ring shape, partial loss of flexion and extension of elbow and total loss of pronation and supination of arm
Ans feedback: adult- funnel shaped; children- vertical
To allow rotation of the radius
1.3. Identify and give the important relations of the radial neck
It is easily fractured
Inferior to radial head
Ans feedback: Posterior interossues nerve
1.3.1.Identify and list the structures attached to the radial styloid
The radial styloid process projects obliquely downward from the distal end of the radius. It serves as the point of attachment for the brachioradialis muscle, radial collateral ligament and extensor retinaculum.
1.4. Identify the important parts of the upper (proximal) ulna.
Olecranon, trochlear notch, coronoid process, ulnar tuberosity, radial notch
1.4.1.What does the olecranon articulate with?
Olecranon fossa of Humerus
1.4.2.What is attached to the coronoid process?
Pronator teres (Ulnar head) , flexor digitorum superficialis,
1.4.3.What does the ulnar head articulate with?
Ulnar notch of radius
1.4.4.Demonstrate the carrying angle.
The lateral angle made by axis of the extended forearm with axis of the arm
1.4.4.1. What are the anatomical factors responsible for producing the carrying angle?
Superior articular surface of coronoid process of ulna is placed obliquely to long axis of ulna
Medial flange of trochlea is 6 mm below the lateral flange
1.4.4.2. What is the function of the carrying angle?
Avoid rubbing of the hip by the forearm during carrying weight or swinging arms- the angle is wider in females because of their wider pelvis
1.4.4.3. What is its clinical importance?
To determine degree of fracture
1.4.5.What is “Student’s elbow?
Olecranon bursitis- because you rest on your coronoid process
2. FUNCTIONAL ORGANIZATION OF THE FOREARM
(Use articulated skeletons & bone sets,plastinated cross section)
2.1.Draw a labeled cross section of the upper third of the forearm showing the
following:
2.1.1. Radius, Ulna and the Interosseous membrane
2.1.2. Superficial and deep fascia
2.1.3. Anterior and posterior compartments
2.1.4. Neuro-vascular structures
2.2. Identify the interosseous membrane
Between the radius and the ulnar
2.2.1. What are its functions?
Divides the forearm into anterior and posterior compartments
Site of attachment for muscles (FDP, FPL, EI)
Allows supination and pronation of forearm
Transmission & dissipation of force
Accessory ligament of radioulnar joints
Transfers load from distal radius to proximal ulna
3.1. Identify the distal attachments of the biceps
Radial tuberosity, Bicipital aponeurosis
3.1.1.What is the function of the bicipital aponeurosis.
Inserts into the deep fascia + ulna giving increased & more even forearm flexion; protects median nerve and brachial artery
Protect the components in the cubital fossa
Reduce the pressure between the bicep and radial tuberosity during pronation and supination
3.1.2.How does the other attachment enable it to act as a supinator?
Biceps brachii main function is at the elbow where it flexes the forearm and supinates the forearm.
3.1.2.1. What is the anatomical basis that we tighten screws clockwise?
Inserts into the posterior aspect of the radial tuberosity
Biceps is a powerful muscle hence supination is more powerful than pronation
3.1.2.2. Which type of lever mechanism does the biceps form?
Class 3 lever
3.2. Identify and list the boundaries of the cubital fossa.
Lateral border- medial border of the brachioradialis muscle, medial border- lateral border of the pronator teres muscle, superior border- hypothetical line between the epicondyles of the humerus
3.2.1.Identify the contents and show their relationship to each other
Lateral of the cubital fossa is the tendon of the biceps brachii muscle followed by the brachial artery and at medial of the cubital fossa is the median nerve.
Also contain the radial nerve and accompanying veins
3.2.2.What is the clinical importance of the fossa?
Common site for venipuncture (the superficial veins)
Site for recording blood pressure
Contents are jeopardized in supracondylar fracture of the humerus
When taking blood pressure reading from a patient, the clinician places the stethoscope over the brachial artery in the cubital fossa.
3.3. Identify the brachioradialis
3.3.1.What is its action?
Accessory flexor of the elbow joint when forearm is mid pronated
Elbow flexion; brings pronated/supinated forearm to mid-position
3.3.2.What is odd about its nerve supply and why?
It is innervated by the radial nerve even though the bulk of the muscle body is visible from the anterior aspect of the forearm.
Radial nerve; flexor muscle supplied by extensor nerve; muscle is on border between 2 compartments means may have components of both
3.4. Identify the pronator teres
3.4.1.What is its nerve supply?
It is innervated by the median nerve
3.4.2.What is its action?
It pronates the forearm (weak flexor)
3.5. List the muscles of the Anterior (flexor-pronator) compartment.
Do a virtual dissection in 4 D Anatomy (http://4danatomy.com/modules )to explore the muscles of the elbow region : Right cubital fossa (anterior-medial view)
3.6. From lateral to medial, identify the muscles originating from the common flexor origin. (medial epicondyle)
Humeral head of pronator teres, Flexor Carpi Radialis, Palmaris Longus, Humeral head of Flexor Carpi Ulnaris Deep: Flexor digitorum superficialis
3.6.1. What is Golfer’s elbow?
Golfer's elbow (medial epicondylitis) causes pain and inflammation in the tendons that connect the forearm to the elbow.
3.7.Which muscles have 2 heads ?
Pronator teres (deep head from coronoid process), Flexor Carpi Ulnaris (fibrous arch to subcutaneous border of ulna), Flexor Digitorum Superficialis (ulnar collateral ligament, coronoid process, fibrous arch to radial shaft origin)
3.7.1.Which main nerves enter the forearm by passing between the 2 heads of each of these muscles?
Pronator teres (Median), Flexor Carpi Ulnaris (Ulnar), Flexor Digitorum Superficialis (Median), Supinator (radial nerve- deep)
3.7.2.What structures pass under the FDS arch?
Ulnar artery and median nerve
Deep and intermediate flexor muscles
3.8.Which nerve supplies the muscles with the common flexor origin?
Median nerve except for flexor carpi ulnaris (ulnar nerve)
3.9. Identify and list the deep forearm flexor muscles.
Flexor digitorum profundus, Flexor pollicis longus, Pronator quadratus
3.9.1.What is their nerve supply?
Flexor digitorum profundus (Medial: Ulnar nerve, Lateral: Median nerve) , Flexor pollicis longus (Median, Anterior interosseous nerve ), Pronator quadratus (Median, Anterior interosseous nerve )
3.10. Identify pronator quadratus.
3.10.1. What are its functions?
Pronates the forearm
Distal radioulnar joint stability (fixator)
3.10.2. What is its nerve supply?
A branch of medial nerve- anterior interosseous nerve
3.10.2.1. From which branch is this nerve derived?
Median Nerve (C8, T1) (C7/8)
3.11. Identify the muscles of the Posterior (extensor- supinator) compartment of the forearm.
Extensor forearm muscles- abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis
3.11.1. What are the nerve supplies of these muscles?
Radial nerve
3.12. List the muscles originating from the common extensor origin.
Extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi, extensor carpi ulnaris
3.12.1. Which nerve supplies the muscles with the common extensor origin?
Extensor Carpi Radialis brevis, Extensor digitorum (Posterior interosseous nerve) , Extensor digiti minimi (Posterior interosseous nerve)
General:(Deep branches of radial nerve)
3.12.2. Which of these muscles have second heads?
Extensor carpi ulnaris- humeral head: lateral epicondyle of humerus and posterior border; ulnar head- olecranon
Supinator
3.12.3. What is ‘tennis elbow’?
Tennis elbow is an inflammation of the tendons that join the forearm muscles on the outside of the elbow. The forearm muscles and tendons become damaged from overuse — repeating the same motions again and again. This leads to pain and tenderness on the outside of the elbow.
Lateral epicondylitis
3.12.4. Identify the Lister’s tubercle
Lister's tubercle or dorsal tubercle of radius is a bony prominence located at the distal end of the radius, palpable on the dorsum of the wrist.
3.13. Identify and list (lateral to medial) the extensor tendons running in compartments over the distal forearm.
Extensor carpi ulnaris, extensor digiti minimi, extensor digitorum, extensor carpi radialis brevis, extensor carpi radialis longus
4. JOINTS (Use articulated skeletons, joint models & bone sets)
Do a virtual dissection in 4 D Anatomy (http://4danatomy.com/modules ) to explore the deepest layer and the elbow joint : Right cubital fossa (anterior-medial view)
4.1.Identify the three articulations of the elbow joint:
4.1.1.Humeroulnar
Trochlea of the humeral condyle and the trochlear notch of the ulna
4.1.2.Humeroradial
Head of the radius and the capitulum of the humerus
4.1.3.Superior radioulnar
Pivot joint- head of radius articulate with radial notch of ulna
4.1.4.What type of synovial joint is each of these joints?
Humeroulnar (simple hinge)
Humeroradial (Ball and socket joint)
Superior radioulnar (pivot joint)
4.2.Why does an elbow joint effusion become distended posteriorly ?
A joint effusion is the increased intra-articular fluid in a joint which causes swelling. In elbow joint effusion its is usually due to the cause of occult fracture (hidden fracture). The joint capsule at the posterior and the anterior of the elbow joint are less dense and are prone to become distended if there is a joint effusion, especially at the olecranon fossa where the larger recess is distended easily.
The capsule is weak anteriorly and posteriorly. Hence, it wil be distended at these sites, especially posteriourly as there is loose capsule posteriorly and the antererior aspect is covered by muscles and deep fascia.
5. VESSELS
5.1. List the blood and nerve supply to each of the compartments of the forearm.
Compartments of the forearm
Arteries blood supply
Nerve supply
Anterior (has 3 layers:
superficial, intermediate, and deep layer)
Radial and ulnar artery
Median nerve (mostly) and Ulnar nerve- flexor carpi ulnari and medial part of flexor digitorum profundus
Posterior (has 2 layers: superficial and deep layer)
Radial artery and posterior and anterior interosseous arteries
Radial nerve
Posterior interosseus nerve
5.2. Identify the origin of the radial artery and its pathway in the forearm.
ORIGIN PATHWAY
Begins at level of radial neck and passes over pronator teres to run deep to brachioradialis to the wrist.
6. NERVES
6.1. Identify the ULNAR NERVE and trace it in the forearm and wrist
PART B: CLINICAL ANATOMY
7. CLINICAL/SURFACE ANATOMY
{Where possible palpate on yourself or on your willing and consenting peers or models/ plastinated specimens the following:}
Palpate/surface mark the following:
7.1. Palpate the following ARTERIES:
• Axillary a. (3rd part) in the axilla (in front of teres major muscle)
• Brachial a. in the cubital fossa (just medial to tendon of biceps brachii)
• Radial pulse (between FCR & brachioradialis, against the radial styloid)
• Ulnar pulse ( Front of wrist, lateral to tendon of FCU)
7.2. Palpate and describe the normal relationship of these 3 bony points:
• Olecranon process
• Medial epicondyle of the humerus
• Lateral epicondyle of the humerus
In a supra condylar # the triangle relationship is maintained as the # lies above these points
7.2.1.What is the clinical importance?
To check if there are golfer and tennis elbow
In elbow dislocation, the olecranon shift posterolaterally and comes to lie in line with the epicondyles which is fixed in flexion.
7.3. Palpate the head of the radius
7.3.1.Demonstrate the ROM of :
• supination and pronation
• Flexion and extension
7.3.2.Demonstrate the axis of their movements
7.3.3.Which joints are involved?
7.3.4.Which muscles are involved?
7.4.Demonstrate on yourself, the following movements of the elbow joint and identifying its attachments, verbalise all the muscles involved for each of the following movements:
• Flexion • Extension • Supination • Pronation
7.5. When a surgeon want to operate on the forearm he needs to have a knowledge of the safe zones for the surgical approach to the bones of the forearm. Give the anatomical basis of the following safe zones of the forearm: https://www2.aofoundation.org/wps/portal/surgery?showPage=approach&contentUrl=srg/21/04-Approaches/21-Safezones.jsp&bone=Radius&segment=Proximal&approach=Safe%20zones%20for%20pin%20insertion&Language=en • Zones in the ulna • Zones in the proximal radius • Zones in the distal radius
7.6. Demonstrate the biceps jerk, triceps jerk, brachioradialis jerk
Biceps jerk
This is most easily done with the patient seated.
Identify the location of the biceps tendon. To do this, have the patient flex at the elbow while you observe and palpate the antecubital fossa. The tendon will look and feel like a thick cord
Support the arm in yours, such that your thumb is resting directly over the biceps tendon (hold their right arm with your right; and vice versa)
Make sure that the biceps muscle is completely relaxed.
It may be difficult to direct your hammer strike such that the force is transmitted directly on to the biceps tendon, and not dissipated amongst the rest of the soft tissue in the area. If you are supporting the patient's arm, place your thumb on the tendon and strike this digit. If the arm is unsupported, place your index or middle fingers firmly against the tendon and strike them with the hammer.
Make sure that the patient's sleeve is rolled up so that you can directly observe the muscle as well as watch the lower arm for movement. A normal response will cause the biceps to contract, drawing the lower arm upwards
Triceps jerk
This is most easily done with the patient seated.
Identify the triceps tendon, a discrete, broad structure that can be palpated (and often seen) as it extends across the elbow to the body of the muscle, located on the back of the upper arm. If you are having trouble clearly identifying the tendon, ask the patient to extend their lower arm at the elbow while you observe and palpate in the appropriate region
The arm can be placed in either of 2 positions:
Gently pull the arm out from the patient's body, such that it roughly forms a right angle at the shoulder. The lower arm should dangle directly downward at the elbow.
Have the patient place their hands on their hips
Either of these techniques will allow the triceps to completely relax.If you are certain as to the precise location of the tendon, strike this area directly with your hammer. If the target is not clearly apparent or the tendon is surrounded by an excessive amount of subcutaneous fat (which might dissipate the force of your strike), place your index or middle finger firmly against the structure. Then strike your finger.
Make sure that the triceps is uncovered, so that you can observe the response. The normal reflex will cause the lower arm to extend at the elbow and swing away from the body. If the patient's hands are on their hips, the arm will not move but the muscle should shorten vigorously
Brachioradialis jerk
This is most easily done with the patient seated. The lower arm should be resting loosely on the patient's lap.
The tendon of the Brachioradialis muscle cannot be seen or well palpated, which makes this reflex a bit tricky to elicit. The tendon crosses the radius (thumb side of the lower arm) approximately 10 cm proximal to the wrist
Strike this area with your reflex hammer. Usually, hitting anywhere in the right vicinity will generate the reflex
Observe the lower arm and body of the Brachioradialis for a response. A normal reflex will cause the lower arm to flex at the elbow and the hand to supinate (turn palm upward)
7.6.1.What are the root values of these reflexes?
Biceps jerk and brachioradialis jerk = C5/C6 Musculotaneous for biceps, radial for brachioradialis
Triceps jerk= C6/C7/C8 (Radial nerve)
7.6.2.What muscles do these correspond to?
Biceps = flexion of forearm
Triceps= extension of forearm
Brachioradialis = flexion of elbow
7.7. What is a “pulled elbow?” Under what circumstances does it occur?
Also known as nursemaid’s elbow where the radius is dislocated, The medical term for the injury is "radial head subluxation and is a common injury of early childhood. Because a young child's bones and muscles are still developing, it typically takes very little force to pull the bones of the elbow partially out of place, making this injury very common. It occurs when a child's hand or wrist and pulls suddenly on the arm. rarely caused by a fall. If a child injures the elbow when falling onto an outstretched hand or directly onto the elbow, it may be a broken bone
7.8. Regarding pronator quadratus.
7.8.1.What is the space of Parona?= mid palmar space
The midpalmar space contains the 2nd, 3rd, and 4th lumbrical muscles and lies posterior to the long flexor tendons to the middle, ring and little fingers. It lies in front of the interossei and the 3rd, 4th and 5th metacarpal bone.
7.8.1.1. What is its clinical application?
The space can be drained by an incision in either the 3rd or 4th web depending on where the pus points.
Infection of the midpalmar space may result from tenosynovitis of the middle and ring fingers or from a web infection which has spread proximally through the lumbrical canals.
7.8.1.2. What limits more proximal spread?
Flexor digitorum profundus, flexor pollicis longus
7.9. What is ‘Volkmann's contracture’?
7.9.1. What is the pathology?
Volkmann’s contracture occurs when there is a lack of blood flow (ischemia) to the forearm. This occurs when there is increased pressure due to swelling, a condition called compartment syndrome (pressure increased, blood flow decreased, caused ischemia, lack of oxygen can supply to the muscle & nerve cells)
7.9.2. Which muscles are involved?
Arm muscle: Superficial and deep flexor muscles on forearm
7.10. Identify the ventral structures at the wrist.
7.10.1. What is their order from medial to lateral?
Ulnar nerve, ulnar artery, flexor digitorum radialis, palmaris longus, median nerve, flexor pollicis longus, radial artery, brachioradialis, abductor pollicis longus, radial nerve (superficial branch)
7.10.2. List the key structures that may be damaged due to “suicide cuts”/deep lacerations of the:
• Radial side of the wrist
Radial artery, radial nerve
• Ulnar side of the wrist
Ulnar nerve, ulnar artery
7.11. How and why would you perform a venipuncture?
How: https://www.youtube.com/watch?v=Ie_nFCL5Hp0
https://phlebotomycoach.com/faqs/what-is-venipuncture
Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.
The site is cleaned with germ-killing medicine (antiseptic).
An elastic band is put around the upper arm to apply pressure to the area. This makes the vein swell with blood.
A needle is inserted into the vein.
The blood collects into an airtight vial or tube attached to the needle.
The elastic band is removed from your arm.
The needle is taken out and the spot is covered with a bandage to stop bleeding.
In infants or young children, a sharp tool called a lancet may be used to puncture the skin and make it bleed. The blood collects onto a slide or test strip. A bandage may be placed over the area if there is any bleeding.
Why: For laboratory testing
Blood is made up of two parts:
Fluid (plasma or serum)
Cells
Plasma is the fluid part that contains substances such as glucose, electrolytes, proteins, and water. Serum is the fluid part that remains after the blood is allowed to clot in a test tube.
Cells in the blood include red blood cells, white blood cells, and platelets.
Blood helps move oxygen, nutrients, waste products, and other materials through the body. It helps control body temperature, fluid balance, and the body's acid-base balance.
Tests on blood or parts of blood may give your provider important clues about your health.
7.11.1. What procedures would you do to make the veins more visible /palpable for venepuncture?
An elastic band is put around the upper arm to apply pressure to the area. This makes the vein swell with blood.
7.12. By applying the same procedures as above on your consenting peer, identify and surface mark the following veins as well as the sites where the veins in the upper limb can be seen or palpated for venipuncture:
• Region of the cubital fossa :
7.12.1. Cephalic vein : ant. to the lat. epicondyle along the anterolateral surface of the biceps brachii
7.12.2. Basilic vein: ant. to the medial epicondyle and medial to the biceps in the lower part of the arm
7.12.3. Medial cubital vein:
The cephalic vein at the lateral side of the forearm passes obliquely across the cubital fossa as the medial cubital vein then continues superiorly to become the basilic vein
7.12.3.1. Why is it commonly used for venipuncture?
-This is because it lies relatively close to the surface and is more prominent (visible) when pressure it’s applied.
-Large enough, can stay in place
(2nd choice is cephalic) (better not to use basilic because brachial artery and median nerve is close to it)
7.12.3.2. Why is the elbow kept extended during venipuncture?
Extension of elbow makes bicipital aponeurosis taut/stretched. Bicipital aponeurosis protects the medial nerve and brachial artery, preventing arterial haemorrhage.
7.12.3.3. What are the common variations of this vein ?
In the cubital fossa, instead of having medial cubital vein, the median antebrachial vein will divide into median cephalic vein (connect to cephalic vein) and median basilic vein (connect to basilic vein). It has an M shape.
7.12.3.4. What is the median vein of the forearm?
• The cephalic vein in the roof of the anatomical snuff box and just posterior to the radial styloid.
• Dorsal venous network on the dorsum of the hand
Median vein of the forearm (median antebrachial vein) begins at the base of the dorsum of the thumb, curves around the lateral side of the wrist, and ascends between the cephalic and basilic veins (sometimes divides into median cephalic and median basilic veins first before joining cephalic and basilic vein respectively)
7.13. How is an arteriovenous fistula created in the forearm for Haemodialysis?
When the surgeon connects an artery to a vein, the vein grows wider and thicker, making it easier to place the needles for dialysis. The AV fistula also has a large diameter that allows your blood to flow out and back into your body quickly. The goal is to allow high blood flow so that the largest amount of blood can pass through the dialyzer.When the surgeon connects an artery to a vein, the vein grows wider and thicker, making it easier to place the needles for dialysis. The AV fistula also has a large diameter that allows your blood to flow out and back into your body quickly. The goal is to allow high blood flow so that the largest amount of blood can pass through the dialyzer.
7.13.1. What vessels are involved?
When the surgeon connects an artery to a vein, the vein grows wider and thicker, making it easier to place the needles for dialysis. The AV fistula also has a large diameter that allows your blood to flow out and back into your body quickly. The goal is to allow high blood flow so that the largest amount of blood can pass through the dialyzer.
7.13.2. How would you check if the AV fistula is working properly?
7.14. What is the importance of ‘Allen’s test’ ?
8. RADIOLOGY {Refer to radiological images in textbooks, Student web resources in Moodle – Grants Atlas & 'Diagnostic Imaging Pathways' http://www.imagingpathways.health.wa.gov.au/index.php/image-galleries/normal-anatomy }
8.1.Study the following :
8.1.1.Elbow joint : AP and Lateral views
Right forearm, Anterior view
Lateral view
8.1.2.Supracondylar fracture of humerus
8.1.2.1. What are the possible vascular complications? Injury to brachial artery and therefore the radial and ulnar arteries will also be affected. This can cause ischemia to the arm as well as the forearm within few hours.
8.1.2.2. How can median nerve palsy, mask a pending compartment syndrome ?
Median nerve palsy(paralysis) is caused by the entrapment/compression to the median nerve. The arteries that are near within the median nerve can also be trapped. Therefore, ischemia will occur. Muscles and nerves can tolerate to to 6 hrs of ischemia and after this fibrous scar tissue replaces the necrotic tissues and causes the involved muscles to shorten permanently producing the flexion deformity known as the ischemic compartment syndrome (Volkmann contracture).
8.1.3.Both Bone forearm fractures
8.1.3.1. What are Monteggia and Galeazzi fractures ?
Monteggia fracture of the Ulnar proximal (MU)
Galeazzi fracture of the Radius distal (GR)
8.1.4.What is a Colles fracture?
Colles fracture is the fracture of the distal forearm and usually the most common fracture is the transverse complete fracture of the distal 2 cm of radius bone. The fracture is the result of forced extension of the hand when person outstretched the upper limb during a fall.
http://www.radiologyassistant.nl/en/p476a23436683b/wristfractures.html#i476a24282794c 8.1.4.1. What deformity does it produce?
When colles fracture happens, the ulnar styloid process can be avulsed (broken off). Since the distal part of the radius is fractured, there is an shortening of the radius and without proper support of the ulnar styloid process. Dinner fork deformity can be seen.
8.4.Identify the hypothenar eminence and its muscles.
Opponens Digiti Minimi, Abductor Digiti Minimi, Flexor Digiti Minimi
8.4.1.What is their nerve supply?
Opponens Digiti Minimi, Abductor Digiti Minimi, Flexor Digiti Minimi (Deep Branch of Ulnar Nerve T1)
8.4.2.What other muscles does this nerve supply?
The deep head of flexor pollicis brevis, adductor pollicis, 3rd and 4th lumbricals, Dorsal and palmar interossei, hypothenar eminence
8.5. Identify the thenar eminence and its mucles.
Abductor pollicis brevis, flexor pollicis brevis, opponens pollicis.
8.5.1.What is their nerve supply and their root values?
Recurrent branch of median nerve (C8, T1) (opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis [Superficial head]).
Deep branch of ulnar nerve (C8, T1) (flexor pollicis brevis [big head]).
Monday, October 29, 2018
Breast, Axilla & Arm
1.Bones
1.1 Identify the characteristic features of the proximal end of the humerus
Head of the humerus, anatomical neck, surgical neck, greater tubercle, lesser tubercle, bicipital groove
1.1.1 Review which muscles are attached to the bicipital groove. What are their respective nerve supplies?
Lateral - pectoralis major ; lateral pectoral nerve and medial pectoral nerve
Floor- latisimmus dorsi; thorcadorsal nerve
Medial - teres major ; lower subscapular nerve
1.1.1.1. Where do these nerves originate and explain why two of them share the same brachial plexus cord origin?
Lateral pectoral nerve - C5-C7 (lateral cord)
Medial pectoral nerve - C8,T1 (medal cord)
Thoracodorsal nerve - C6-C8 (posterior cord)
Lower subscapular nerve - C5,C6 (posterior cord)
Both thoracodorsal nerve and lower subscapular nerve are mainly extensor muscles and had common functions so they share a common origin.
1.2. Identify the characteristic features of the humeral shaft including the deltoid tuberosity.
Features:
The deltoid tuberosity is a roughened surface on the lateral side for deltoid muscle attachment.
Spiral groove (radial sulcus) is an oblique groove which lies posteriorly in which the radial nerve and profunda brachii artery lie.
The humerus shaft is the site of attachment for various muscles.
Anteriorly – coracobrachialis, deltoid, brachialis, brachioradialis.
Posteriorly – medial and lateral heads of the triceps (the spiral groove demarcates their respective origins)
1.3 Identify the spiral groove of the humerus
Ans: radial groove, located at the lateral border of the humerus
What does it demarcate (set the boundaries or limit of)?
Lateral and medial head of triceps
Identify its contents?
Radial nerve and profunda brachii vessels
2. Muscles
2.1. What is Axilla?
Axilla is the pyramidal-shaped space deep to the skin, located between arm and thorax. It is the region where neurovascular structures like brachial plexus pass through to innervate muscles of the upper limb.
http://act.downstate.edu/courseware/haonline/labs/l05/ov0100.htm Perform a virtual dissection in 4 D Anatomy (http://4danatomy.com/modules ) to explore the Axilla: Left Shoulder (upper Lateral View)
2.2. Identify the boundaries of the axillary space (ANM Upperlimb Regions 09)
Base- skin and associated fascia of the armpit.
Apex - cervicoaxillary canal
4 walls :
anterior - pec major, minor
Posterior - subscapularis, latissimus dorsi, teres major, scapula
Lateral - the floor of the bicipital groove of humerus
Medial - upper ribs (2nd to 6th) and the serratus anterior muscle
http://act.downstate.edu/courseware/haonline/labs/l05/ov0200.htm
2.3. Identify the boundaries of the cervicoaxillary canal (apex of the axilla)
Medially: 1st rib
Anteriorly: Clavicle
Posteriorly: the Superior edge of the scapula
2.3.1. What structures pass through it?
Brachial plexus, axillary artery, vein, lymph nodes
Ans: Long thoracic nerve traverses this passageway in addition to axillary blood vessels and the brachial plexus
2.4. Identify the flexor compartment of the arm (ANM Upperlimb Dissection 14)
Prime mover: Pectoralis major(clavicular head); deltoid (clavicular and anterior acromial parts)
Synergist: Coracobrachialis (assisted by biceps brachii)
Ans: coracobrachialis, biceps, brachialis
Musculocutaneous
2.4.1. Identify its major muscles and its nerve.
Pectoralis Major: Lateral and medial pectoral nerve; clavicular head (C5&6), sternocostal head (C7, C8, T1)
Deltoid: Axillary nerve (C5, C6)
Ans: Surgical neck of humerus, long head of triceps, subscapularis (anteriorly)/ teres minor posteriorly, teres major
Axillary nerve, posterior circumflex humeral artery
2.4.2. Identify the 2 heads of the biceps and their attachment on the skeleton.
Origin:
Long head: supraglenoid tubercle of the scapula
Short head: coracoid process of the scapula
Attachment: Radial tuberosity and bicipital aponeurosis (ulna)
2.4.2.1. What is its action?
(a)Supinates forearm and, when it is supine
(b)Flexes forearm and elbow
(c)Short head resists dislocation of shoulder joint
2.4.3. Identify brachialis. and its attachments on the skeleton.
Origin - distal half of anterior surface of the humerus
Insertion- coronoid process and tuberosity of ulna
2.4.3.1. What is its action?
Elbow flexion
2.4.4. Identify coracobrachialis and its attachments
O - tip of coracoid process of scapula
I - midshaft of humerus medially
2.5. What is its action?
Shoulder flexion & adduction, resist shoulder dislocation
2.6. Identify 3 heads of the triceps and its insertion.
Proximal attachment:
Long head: infraglenoid tubercle of scapula
Lateral head: posterior surface of the humerus, superior to radial groove
Medial head: posterior surface of the humerus, inferior to radial groove
Insertion: Proximal end of olecranon of ulna and fascia of forearm
2.6.1. What is its action?
Chief extensor of the shoulder (long head) & elbow extension; long head resist dislocation of the humerus; especially important during adduction
2.7. Study the plastinated cross-section of the arm. Draw a labelled cross-section of the middle third of the arm showing the following :
2.7.1. Superficial and deep fascia and its extensions
2.7.2. The anterior and posterior compartments
2.7.3. Neurovascular structures
The surgical neck of humerus, long head of triceps, subscapularis (anteriorly)/ teres minor posteriorly, teres major
3. Vessels
3.1. Identify the subclavian, axillary and the brachial arteries.
3.2. Identify the landmarks indicating the junction of the subclavian and axillary arteries as well as where the axillary continues as the brachial artery.
3.2.1. At what level does the brachial artery end?
The neck of radius which branches into radial and ulnar arteries
3.3. Identify the axillary artery.
(ANM Upperlimb System 48)http://act.downstate.edu/courseware/haonline/labs/l05/060103.htm
3.3.1. Where does it become brachial?
At the inferior border of teres major
3.3.2. How are its 3 parts defined?
1st Part: Medial border of pectoralis minor, lateral border of the first rib
2nd Part: Posterior to the pectoralis minor
3rd Part: Lateral border of pectoralis minor, lower border of Teres Major
3.3.3. List the branches from each part
1st Part: Superior Thoracic
2nd Part: Lateral Thoracic, Thoraco-aromial
3rd Part: Subscapular (biggest), Anterior and posterior circumflex humeral
3.3.4. How is the scapular anastomosis formed and what is its clinical significance?
The transverse cervical artery from the subclavian, usually the first part, occasionally the third part, has a descending branch (the dorsal scapular artery) which accompanies the dorsal scapular nerve. It runs down the vertebral border of the scapula to its inferior angle. The suprascapular artery from the subclavian, usually the first part (thyrocervical trunk in common with the transverse cervical) but occasionally the third part, crosses over the transverse ligament of the scapular notch, passes through the supraspinous fossa, turns around the lateral border of the spine of the scapula and supplies the infraspinous fossa as far as the inferior angle. The subscapular artery, branching from the third part of the axillary, supplies the subscapularis muscle in the subscapular fossa as far as the inferior angle. Its circumflex scapular branch enters the infraspinous fossa on the dorsal surface of the bone. All the vessels anastomose, thus connecting the first part of the subclavian with the third part of the axillary artery. The companion veins form corresponding anastomoses.
Ans: all arteries except the circumflex humeral artery anastomose to connect the first part of the subclavian with the third part of the axillary artery.
Many arterial anastomoses (communications between arteries) occur around the scapula. Several arteries join to form networks on the anterior and posterior of the scapula: the dorsal scapular, suprascapular and subscapular (via the circumflex scapular branch). The importance of the collateral circulation made possible by theses anastomoses becomes apparent when ligation of a lacerated subclavian or axillary artery is necessary. For example, the axillary artery may have to be ligated between the 1st rib and subscapular artery: in other cases, vascular stenosis of the axillary artery may result from an atherosclerotic lesion that causes reduced blood flow. In either case, the direction of blood flow in the subscapular artery reversed, enabling blood to reach the third part of the axillary artery. Note that the subscapular artery receives blood through several anastomoses with the suprascapular artery, transverse cervical artery and intercostal arteries. Slow occlusion of an artery (resulting from a disease) often enables sufficient collateral circulation to develop, preventing ischemia. Sudden occlusion usually does not allow sufficient time for adequate collateral circulation to develop as a result, ischemia of the upper limb occurs. Abrupt surgical ligation of the axillary artery between the origins of the subscapular and the profunda bracii artery will cut off the blood supply to the arm because the collateral circulation is inadequate.
3.3.5. What is the major branch of the brachial artery in the arm?
Profunda brachii artery
It allows blood to flow past the joint in case of occlusion, damage, or pinching of the following scapular arteries: Transverse cervical artery.
3.4. Identify the suprascapular nerve & vessels and their origin.
Tyrocervical origin (a direct branch of 1st part pf subclavian artery)
Superior trunk from C5,6,4
.
3.4.1. What is the position & relations of suprascapular ligament?
Passes almost directly posteriorly to the suprascapular notch; passes through this under suprascapular ligament to supraspinatus & infraspinatus. Ligament converts notch into a foramen. The nerve goes under, the artery goes over. Veins have variablecourse.
3.5. Identify the cephalic vein in the shoulder. (ANM Upperlimb System 50)
3.5.1. At what location does this vein enter the axillary vein and how?
The deltopectoral triangle and it empties into the axillary vein
Ans: runs in the groove between pectoralis major & deltoid, penetrates the
clavipectoral fascia to enter the axillary vein
3.5.2. Identify the cephalic vein located in the arm
The surgical neck of humerus, long head of triceps, subscapularis (anteriorly(/teres minor
posteriorly, teres major
Axillary nerve, posterior circumflex humeral artery
3.5.3. Is it pre-axial or post-axial? Pre-axial
3.5.4. Where does it arise? The lateral end of the dorsal venous arch of the hand
3.6. Identify the deep veins of the arm
Brachial veins, radial veins, ulnar veins
Perforating veins- run between the deep and superficial veins of the upper limb, connecting the two systems
3.6.1. What are vena commitantes?
It refers to a vein that is usually paired, with both veins lying on the sides of an artery.
2 or 3 veins that wrap around a peripheral artery
3.6.2. What is their function?
They are found in close proximity to arteries so that the pulsations of the artery aid venous return
Heat exchange, increased flow due to arterial pulsation
3.7. Identify the brachial vein
3.7.1. Where does it pierce the deep fascia?
The brachial fascia above the medial epicondyle or sometimes as high as the mid-arm
3.7.2. What structural changes occur at this level in the arm?
Cross-section change of humeral shaft- upper cylindrical lower triangle
Insertion of coracobrachialis & deltoid
Upper attachments of medial & lateral IM septa
Brachial artery- medial to the front of the arm
Entry of radial nerve and profunda brachii to the spiral groove
Basilic vein pierces the deep fascia
MAB nerve- becomes subcutaneous
4. Nerves
4.1. With the aid of a labelled diagram, describe the formation of the brachial plexus. Using models/specimens/atlas:
4.1.1. Identify the roots, trunks, divisions and cords of the brachial plexus.
http://act.downstate.edu/courseware/haonline/labs/l0 5/020203.htm
4.1.2. Name & identify the branches of the brachial plexus and give their root values.
(ANM Upperlimb System 42) (ANM Upperlimb Region 11) Do a virtual dissection in
4 D Anatomy (http://4danatomy.com/modules ) to explore the brachial plexus after
removal of the clavicle: Left Shoulder (upper Lateral View)
4.2. Identify the Serratus anterior and its nerve supply – the long thoracic nerve
Serratus anterior has a proximal attachment of external surfaces of the lateral parts of the 1st rib to 8th ribs, and its distal attachment is the anterior surface of the medial border of the scapula.
Long thoracic nerve originates in the posterior aspect of anterior rami of C5, C6 and C7. It passes through cervico-axillary canal descending posterior to C8 and T1 roots of plexus; runs inferiorly on the superficial surface of serratus anterior.
http://act.downstate.edu/courseware/haonline/labs/l05/090102.ht m
4.3. Identify the axillary nerve & describe its origin, root value & distribution. http://act.downstate.edu/courseware/haonline/labs/l05/08 0103.htm
4.3.1. From what cord does it originate? (ANM Upperlimb System 46)
The posterior cord of the brachial plexus.
4.3.2. What muscles does this nerve supply?
Teres minor and deltoid muscles.
4.3.3. Explain the relevance of Hilton’s law
Hilton’s Law: the nerve supplying the muscles extending directly across and acting at a given joint not only supplies the muscle, but also innervate the joint and the skin overlying the muscle. Axillary nerve not only innervates the teres minor and deltoid muscle but also the shoulder joint (glenohumeral joint) and the skin of superolateral arm (over inferior part of deltoid).
Defined as the regimental badge area or the small area around insertion. The axillary
the nerve must supply the shoulder joint
4.4. Identify the musculocutaneous nerve. (ANM Upperlimb System 43)
4.4.1. Describe its pathway.
Piercing the coracobrachialis when exiting the axilla; descends between biceps brachii and brachialis. Supplying both; continues as the lateral cutaneous nerve of forearm
Continuation of lateral cord passing through coracobrachialis to biceps & brachialis, finishing lateral to biceps as the lateral cutaneous nerve of forearm
4.4.2. From what nerve roots does it arise? C5, C6, C7
4.4.3. How will you test this nerve?
Tests on the sensory of the lateral aspect of the forearm, elbow flexion
4.5. Identify the Radial nerve. (ANM Upperlimb System 47)
4.5.1. From what nerve roots does it arise? C5,6,7,8 and T1
5. VISCERAL/BREAST
5.1. Breast
5.1.1. Identify the structures of the Breast
5.1.2. What is the arterial supply of the breast?
Lateral thoracic artery, internal thoracic artery (via medial mammary brs of, perforating brs and ant. Intercoastal brs), posterior intercoastal artery (branch of thoracic aorta in the 2nd, 3rd and 4th intercoastal spaces), thoracoacromial artery
Medial aspect: internal thoracic artery (a branch of the subclavian artery)
Lateral part:-
Lateral thoracic, thoracoacromial branches, superior thoracic and subscapular
(axillary artery)
Lateral mammary branches (posterior intercostal arteries from the aorta)
Mammary branch- anterior intercostal artery
Veins correspond with arteries - drain into axillary and internal thoracic veins
5.1.2.1. Which branches are encountered in the axillary dissection of a radical
mastectomy?
Long thoracic nerve, Axillary artery and vein, brachial plexus, thoracodorsal artery, vein and nerve, subscapular artery
5.2.Breast Development :
5.2.1. How does the breast develop?
5.2.2. What is the embryological explanation of accessory nipples (polythelia)?
Accessory nipples develop while a human embryo is developing in the womb.
During the fourth week of pregnancy, the embryo’s two milk lines, which are made of ridged ectoderm tissue, thicken.
Normally, the milk line tissue stays thick and forms your nipples while the rest of the thickened skin softens up again. But in some cases, parts of the milk line ridges don’t become regular ectoderm tissue again. When this happens, supernumerary nipples can appear where the milk tissue stayed thick and ridged after birth and development into adulthood.
5.3. SPREAD OF BREAST CANCER
5.3.1. How may Cooper’s ligaments involvement be evident in breast carcinoma?
Breast Dimpling: Cooper ligaments shorten
Fixity of lump: due to suspensory Cooper’s ligament
5.3.2. How may the carcinoma spread:
5.3.2.1. via lymphatics?
When cancer cells break away from a tumour, they can travel to other areas of the body through the lymph system. Then they must move through the vessel wallto flow with the lymph to a new organ or lymph node.
Lymphatic vessels carry cancer cells from the breast to the lymph nodes,
chiefly those in the axilla. The cells lodge in the nodes, producing nests of tumourcells (metastases). Abundant communications among llymphatic pathwaysand among axillary, cervical and parasternal nodes may also ccause metastasesfrom the breast or the abdomen. Because most of the lymphatic drainage of the breast is to the axillary lymph nodes, they are the most common site of metastasis from a breast cancer.
5.3.2.2. via veins?
The cancer cell must move through the wall of the capillary and into the tissue of the organ close by.
Spread from the breast through the posterior intercostal veins that drain into the azygos/ Hemi-azygos system of veins alongside the bodies of the vertebra and communicate with the internal vertebral venous plexus surrounding the spinal cord. Then, it spread to the cranium and brain.
5.3.2.3. Directly?
some cells from primary cancer must break away, travel to another part of the body and start growing there. Cancer cells don't stick together as well as normal cells do. They may also produce substances that stimulate them to move. Can spread contiguity (invasion of adjacent tissue). When breast cancer cells invade the retromammary space, attach to or invade the pectoral fascia overlying the pectoralis major, or metastasize to the interpectoral nodes, the breast elevates when the muscle contracts.
6. CLINICAL ANATOMY
Palpate and demonstrate on your willing and consenting peers the following:
6.1. Axillary lymph nodes
6.2. Anterior & posterior axillary folds
6.2.1.1. What constitutes the Ant Axillary and the Post Axillary folds?
Post: Latissimus dorsi, teres major muscle and subscapularis
Ant: lateral border of pectoralis major and minor muscle
6.3. With the arm by the side, forearm supported and pectoral muscles relaxed, palpate the axilla for:
6.3.1. Medial wall (ribs/serratus anterior)
6.3.2. Lateral wall (coracobrachialis/biceps brachii)
6.3.3. Head of the humerus
6.3.4. Axillary artery
6.4. How may an axillary nerve get damaged?
Fracture of the humeral neck or dislocation
6.4.1.1. How would you assess this clinically?
The weakness of shoulder abduction (15-90 degrees), wasting of the deltoid, regimental badge anaesthesia over the deltoid muscle
6.5. Regarding the features of humeral shaft
6.5.1. Identify the common site of its fracture explain the types of fracture and their injury mechanism.
1.1 Identify the characteristic features of the proximal end of the humerus
Head of the humerus, anatomical neck, surgical neck, greater tubercle, lesser tubercle, bicipital groove
1.1.1 Review which muscles are attached to the bicipital groove. What are their respective nerve supplies?
Lateral - pectoralis major ; lateral pectoral nerve and medial pectoral nerve
Floor- latisimmus dorsi; thorcadorsal nerve
Medial - teres major ; lower subscapular nerve
1.1.1.1. Where do these nerves originate and explain why two of them share the same brachial plexus cord origin?
Lateral pectoral nerve - C5-C7 (lateral cord)
Medial pectoral nerve - C8,T1 (medal cord)
Thoracodorsal nerve - C6-C8 (posterior cord)
Lower subscapular nerve - C5,C6 (posterior cord)
Both thoracodorsal nerve and lower subscapular nerve are mainly extensor muscles and had common functions so they share a common origin.
1.2. Identify the characteristic features of the humeral shaft including the deltoid tuberosity.
Features:
The deltoid tuberosity is a roughened surface on the lateral side for deltoid muscle attachment.
Spiral groove (radial sulcus) is an oblique groove which lies posteriorly in which the radial nerve and profunda brachii artery lie.
The humerus shaft is the site of attachment for various muscles.
Anteriorly – coracobrachialis, deltoid, brachialis, brachioradialis.
Posteriorly – medial and lateral heads of the triceps (the spiral groove demarcates their respective origins)
1.3 Identify the spiral groove of the humerus
Ans: radial groove, located at the lateral border of the humerus
What does it demarcate (set the boundaries or limit of)?
Lateral and medial head of triceps
Identify its contents?
Radial nerve and profunda brachii vessels
2. Muscles
2.1. What is Axilla?
Axilla is the pyramidal-shaped space deep to the skin, located between arm and thorax. It is the region where neurovascular structures like brachial plexus pass through to innervate muscles of the upper limb.
http://act.downstate.edu/courseware/haonline/labs/l05/ov0100.htm Perform a virtual dissection in 4 D Anatomy (http://4danatomy.com/modules ) to explore the Axilla: Left Shoulder (upper Lateral View)
2.2. Identify the boundaries of the axillary space (ANM Upperlimb Regions 09)
Base- skin and associated fascia of the armpit.
Apex - cervicoaxillary canal
4 walls :
anterior - pec major, minor
Posterior - subscapularis, latissimus dorsi, teres major, scapula
Lateral - the floor of the bicipital groove of humerus
Medial - upper ribs (2nd to 6th) and the serratus anterior muscle
http://act.downstate.edu/courseware/haonline/labs/l05/ov0200.htm
2.3. Identify the boundaries of the cervicoaxillary canal (apex of the axilla)
Medially: 1st rib
Anteriorly: Clavicle
Posteriorly: the Superior edge of the scapula
2.3.1. What structures pass through it?
Brachial plexus, axillary artery, vein, lymph nodes
Ans: Long thoracic nerve traverses this passageway in addition to axillary blood vessels and the brachial plexus
2.4. Identify the flexor compartment of the arm (ANM Upperlimb Dissection 14)
Prime mover: Pectoralis major(clavicular head); deltoid (clavicular and anterior acromial parts)
Synergist: Coracobrachialis (assisted by biceps brachii)
Ans: coracobrachialis, biceps, brachialis
Musculocutaneous
2.4.1. Identify its major muscles and its nerve.
Pectoralis Major: Lateral and medial pectoral nerve; clavicular head (C5&6), sternocostal head (C7, C8, T1)
Deltoid: Axillary nerve (C5, C6)
Ans: Surgical neck of humerus, long head of triceps, subscapularis (anteriorly)/ teres minor posteriorly, teres major
Axillary nerve, posterior circumflex humeral artery
2.4.2. Identify the 2 heads of the biceps and their attachment on the skeleton.
Origin:
Long head: supraglenoid tubercle of the scapula
Short head: coracoid process of the scapula
Attachment: Radial tuberosity and bicipital aponeurosis (ulna)
2.4.2.1. What is its action?
(a)Supinates forearm and, when it is supine
(b)Flexes forearm and elbow
(c)Short head resists dislocation of shoulder joint
2.4.3. Identify brachialis. and its attachments on the skeleton.
Origin - distal half of anterior surface of the humerus
Insertion- coronoid process and tuberosity of ulna
2.4.3.1. What is its action?
Elbow flexion
2.4.4. Identify coracobrachialis and its attachments
O - tip of coracoid process of scapula
I - midshaft of humerus medially
2.5. What is its action?
Shoulder flexion & adduction, resist shoulder dislocation
2.6. Identify 3 heads of the triceps and its insertion.
Proximal attachment:
Long head: infraglenoid tubercle of scapula
Lateral head: posterior surface of the humerus, superior to radial groove
Medial head: posterior surface of the humerus, inferior to radial groove
Insertion: Proximal end of olecranon of ulna and fascia of forearm
2.6.1. What is its action?
Chief extensor of the shoulder (long head) & elbow extension; long head resist dislocation of the humerus; especially important during adduction
2.7. Study the plastinated cross-section of the arm. Draw a labelled cross-section of the middle third of the arm showing the following :
2.7.1. Superficial and deep fascia and its extensions
2.7.2. The anterior and posterior compartments
2.7.3. Neurovascular structures
The surgical neck of humerus, long head of triceps, subscapularis (anteriorly)/ teres minor posteriorly, teres major
3. Vessels
3.1. Identify the subclavian, axillary and the brachial arteries.
3.2. Identify the landmarks indicating the junction of the subclavian and axillary arteries as well as where the axillary continues as the brachial artery.
3.2.1. At what level does the brachial artery end?
The neck of radius which branches into radial and ulnar arteries
3.3. Identify the axillary artery.
(ANM Upperlimb System 48)http://act.downstate.edu/courseware/haonline/labs/l05/060103.htm
3.3.1. Where does it become brachial?
At the inferior border of teres major
3.3.2. How are its 3 parts defined?
1st Part: Medial border of pectoralis minor, lateral border of the first rib
2nd Part: Posterior to the pectoralis minor
3rd Part: Lateral border of pectoralis minor, lower border of Teres Major
3.3.3. List the branches from each part
1st Part: Superior Thoracic
2nd Part: Lateral Thoracic, Thoraco-aromial
3rd Part: Subscapular (biggest), Anterior and posterior circumflex humeral
3.3.4. How is the scapular anastomosis formed and what is its clinical significance?
The transverse cervical artery from the subclavian, usually the first part, occasionally the third part, has a descending branch (the dorsal scapular artery) which accompanies the dorsal scapular nerve. It runs down the vertebral border of the scapula to its inferior angle. The suprascapular artery from the subclavian, usually the first part (thyrocervical trunk in common with the transverse cervical) but occasionally the third part, crosses over the transverse ligament of the scapular notch, passes through the supraspinous fossa, turns around the lateral border of the spine of the scapula and supplies the infraspinous fossa as far as the inferior angle. The subscapular artery, branching from the third part of the axillary, supplies the subscapularis muscle in the subscapular fossa as far as the inferior angle. Its circumflex scapular branch enters the infraspinous fossa on the dorsal surface of the bone. All the vessels anastomose, thus connecting the first part of the subclavian with the third part of the axillary artery. The companion veins form corresponding anastomoses.
Ans: all arteries except the circumflex humeral artery anastomose to connect the first part of the subclavian with the third part of the axillary artery.
Many arterial anastomoses (communications between arteries) occur around the scapula. Several arteries join to form networks on the anterior and posterior of the scapula: the dorsal scapular, suprascapular and subscapular (via the circumflex scapular branch). The importance of the collateral circulation made possible by theses anastomoses becomes apparent when ligation of a lacerated subclavian or axillary artery is necessary. For example, the axillary artery may have to be ligated between the 1st rib and subscapular artery: in other cases, vascular stenosis of the axillary artery may result from an atherosclerotic lesion that causes reduced blood flow. In either case, the direction of blood flow in the subscapular artery reversed, enabling blood to reach the third part of the axillary artery. Note that the subscapular artery receives blood through several anastomoses with the suprascapular artery, transverse cervical artery and intercostal arteries. Slow occlusion of an artery (resulting from a disease) often enables sufficient collateral circulation to develop, preventing ischemia. Sudden occlusion usually does not allow sufficient time for adequate collateral circulation to develop as a result, ischemia of the upper limb occurs. Abrupt surgical ligation of the axillary artery between the origins of the subscapular and the profunda bracii artery will cut off the blood supply to the arm because the collateral circulation is inadequate.
3.3.5. What is the major branch of the brachial artery in the arm?
Profunda brachii artery
It allows blood to flow past the joint in case of occlusion, damage, or pinching of the following scapular arteries: Transverse cervical artery.
3.4. Identify the suprascapular nerve & vessels and their origin.
Tyrocervical origin (a direct branch of 1st part pf subclavian artery)
Superior trunk from C5,6,4
.
3.4.1. What is the position & relations of suprascapular ligament?
Passes almost directly posteriorly to the suprascapular notch; passes through this under suprascapular ligament to supraspinatus & infraspinatus. Ligament converts notch into a foramen. The nerve goes under, the artery goes over. Veins have variablecourse.
3.5. Identify the cephalic vein in the shoulder. (ANM Upperlimb System 50)
3.5.1. At what location does this vein enter the axillary vein and how?
The deltopectoral triangle and it empties into the axillary vein
Ans: runs in the groove between pectoralis major & deltoid, penetrates the
clavipectoral fascia to enter the axillary vein
3.5.2. Identify the cephalic vein located in the arm
The surgical neck of humerus, long head of triceps, subscapularis (anteriorly(/teres minor
posteriorly, teres major
Axillary nerve, posterior circumflex humeral artery
3.5.3. Is it pre-axial or post-axial? Pre-axial
3.5.4. Where does it arise? The lateral end of the dorsal venous arch of the hand
3.6. Identify the deep veins of the arm
Brachial veins, radial veins, ulnar veins
Perforating veins- run between the deep and superficial veins of the upper limb, connecting the two systems
3.6.1. What are vena commitantes?
It refers to a vein that is usually paired, with both veins lying on the sides of an artery.
2 or 3 veins that wrap around a peripheral artery
3.6.2. What is their function?
They are found in close proximity to arteries so that the pulsations of the artery aid venous return
Heat exchange, increased flow due to arterial pulsation
3.7. Identify the brachial vein
3.7.1. Where does it pierce the deep fascia?
The brachial fascia above the medial epicondyle or sometimes as high as the mid-arm
3.7.2. What structural changes occur at this level in the arm?
Cross-section change of humeral shaft- upper cylindrical lower triangle
Insertion of coracobrachialis & deltoid
Upper attachments of medial & lateral IM septa
Brachial artery- medial to the front of the arm
Entry of radial nerve and profunda brachii to the spiral groove
Basilic vein pierces the deep fascia
MAB nerve- becomes subcutaneous
4. Nerves
4.1. With the aid of a labelled diagram, describe the formation of the brachial plexus. Using models/specimens/atlas:
4.1.1. Identify the roots, trunks, divisions and cords of the brachial plexus.
http://act.downstate.edu/courseware/haonline/labs/l0 5/020203.htm
4.1.2. Name & identify the branches of the brachial plexus and give their root values.
(ANM Upperlimb System 42) (ANM Upperlimb Region 11) Do a virtual dissection in
4 D Anatomy (http://4danatomy.com/modules ) to explore the brachial plexus after
removal of the clavicle: Left Shoulder (upper Lateral View)
4.2. Identify the Serratus anterior and its nerve supply – the long thoracic nerve
Serratus anterior has a proximal attachment of external surfaces of the lateral parts of the 1st rib to 8th ribs, and its distal attachment is the anterior surface of the medial border of the scapula.
Long thoracic nerve originates in the posterior aspect of anterior rami of C5, C6 and C7. It passes through cervico-axillary canal descending posterior to C8 and T1 roots of plexus; runs inferiorly on the superficial surface of serratus anterior.
http://act.downstate.edu/courseware/haonline/labs/l05/090102.ht m
4.3. Identify the axillary nerve & describe its origin, root value & distribution. http://act.downstate.edu/courseware/haonline/labs/l05/08 0103.htm
4.3.1. From what cord does it originate? (ANM Upperlimb System 46)
The posterior cord of the brachial plexus.
4.3.2. What muscles does this nerve supply?
Teres minor and deltoid muscles.
4.3.3. Explain the relevance of Hilton’s law
Hilton’s Law: the nerve supplying the muscles extending directly across and acting at a given joint not only supplies the muscle, but also innervate the joint and the skin overlying the muscle. Axillary nerve not only innervates the teres minor and deltoid muscle but also the shoulder joint (glenohumeral joint) and the skin of superolateral arm (over inferior part of deltoid).
Defined as the regimental badge area or the small area around insertion. The axillary
the nerve must supply the shoulder joint
4.4. Identify the musculocutaneous nerve. (ANM Upperlimb System 43)
4.4.1. Describe its pathway.
Piercing the coracobrachialis when exiting the axilla; descends between biceps brachii and brachialis. Supplying both; continues as the lateral cutaneous nerve of forearm
Continuation of lateral cord passing through coracobrachialis to biceps & brachialis, finishing lateral to biceps as the lateral cutaneous nerve of forearm
4.4.2. From what nerve roots does it arise? C5, C6, C7
4.4.3. How will you test this nerve?
Tests on the sensory of the lateral aspect of the forearm, elbow flexion
4.5. Identify the Radial nerve. (ANM Upperlimb System 47)
4.5.1. From what nerve roots does it arise? C5,6,7,8 and T1
5. VISCERAL/BREAST
5.1. Breast
5.1.1. Identify the structures of the Breast
5.1.2. What is the arterial supply of the breast?
Lateral thoracic artery, internal thoracic artery (via medial mammary brs of, perforating brs and ant. Intercoastal brs), posterior intercoastal artery (branch of thoracic aorta in the 2nd, 3rd and 4th intercoastal spaces), thoracoacromial artery
Medial aspect: internal thoracic artery (a branch of the subclavian artery)
Lateral part:-
Lateral thoracic, thoracoacromial branches, superior thoracic and subscapular
(axillary artery)
Lateral mammary branches (posterior intercostal arteries from the aorta)
Mammary branch- anterior intercostal artery
Veins correspond with arteries - drain into axillary and internal thoracic veins
5.1.2.1. Which branches are encountered in the axillary dissection of a radical
mastectomy?
Long thoracic nerve, Axillary artery and vein, brachial plexus, thoracodorsal artery, vein and nerve, subscapular artery
5.2.Breast Development :
5.2.1. How does the breast develop?
5.2.2. What is the embryological explanation of accessory nipples (polythelia)?
Accessory nipples develop while a human embryo is developing in the womb.
During the fourth week of pregnancy, the embryo’s two milk lines, which are made of ridged ectoderm tissue, thicken.
Normally, the milk line tissue stays thick and forms your nipples while the rest of the thickened skin softens up again. But in some cases, parts of the milk line ridges don’t become regular ectoderm tissue again. When this happens, supernumerary nipples can appear where the milk tissue stayed thick and ridged after birth and development into adulthood.
5.3. SPREAD OF BREAST CANCER
5.3.1. How may Cooper’s ligaments involvement be evident in breast carcinoma?
Breast Dimpling: Cooper ligaments shorten
Fixity of lump: due to suspensory Cooper’s ligament
5.3.2. How may the carcinoma spread:
5.3.2.1. via lymphatics?
When cancer cells break away from a tumour, they can travel to other areas of the body through the lymph system. Then they must move through the vessel wallto flow with the lymph to a new organ or lymph node.
Lymphatic vessels carry cancer cells from the breast to the lymph nodes,
chiefly those in the axilla. The cells lodge in the nodes, producing nests of tumourcells (metastases). Abundant communications among llymphatic pathwaysand among axillary, cervical and parasternal nodes may also ccause metastasesfrom the breast or the abdomen. Because most of the lymphatic drainage of the breast is to the axillary lymph nodes, they are the most common site of metastasis from a breast cancer.
5.3.2.2. via veins?
The cancer cell must move through the wall of the capillary and into the tissue of the organ close by.
Spread from the breast through the posterior intercostal veins that drain into the azygos/ Hemi-azygos system of veins alongside the bodies of the vertebra and communicate with the internal vertebral venous plexus surrounding the spinal cord. Then, it spread to the cranium and brain.
5.3.2.3. Directly?
some cells from primary cancer must break away, travel to another part of the body and start growing there. Cancer cells don't stick together as well as normal cells do. They may also produce substances that stimulate them to move. Can spread contiguity (invasion of adjacent tissue). When breast cancer cells invade the retromammary space, attach to or invade the pectoral fascia overlying the pectoralis major, or metastasize to the interpectoral nodes, the breast elevates when the muscle contracts.
6. CLINICAL ANATOMY
Palpate and demonstrate on your willing and consenting peers the following:
6.1. Axillary lymph nodes
6.2. Anterior & posterior axillary folds
6.2.1.1. What constitutes the Ant Axillary and the Post Axillary folds?
Post: Latissimus dorsi, teres major muscle and subscapularis
Ant: lateral border of pectoralis major and minor muscle
6.3. With the arm by the side, forearm supported and pectoral muscles relaxed, palpate the axilla for:
6.3.1. Medial wall (ribs/serratus anterior)
6.3.2. Lateral wall (coracobrachialis/biceps brachii)
6.3.3. Head of the humerus
6.3.4. Axillary artery
6.4. How may an axillary nerve get damaged?
Fracture of the humeral neck or dislocation
6.4.1.1. How would you assess this clinically?
The weakness of shoulder abduction (15-90 degrees), wasting of the deltoid, regimental badge anaesthesia over the deltoid muscle
6.5. Regarding the features of humeral shaft
6.5.1. Identify the common site of its fracture explain the types of fracture and their injury mechanism.
Midshaft of humerus
Transverse (direct trauma- hit by a car), spiral (indirect twisting- wrestling), oblique (direct & indirect), comminuted (shotgun, osteoporosis)
6.5.1.1. What neurovascular structures may be injured and what is the clinical importance? Radial (most common)/ulnar/median nerve damage, up to 90% of patients with a closed humeral fracture with radial nerve injury will have a resolution of neuropraxia within three to four months following the injury.
Radial nerve, profunda brachii artery & vein
Large haematoma, muscle necrosis, compartment syndrome, peripheral ischaemia due to swelling, radial nerve palsy (wrist drop & sensory loss)
6.6. Regarding the biceps.
6.6.1.1. Why is it commonly injured?
Involved in many actions Crosses 2 joints (compare to hamstrings in the thigh)
6.6.1.2. Name 2 clinical conditions of biceps.
Proximal biceps tendinitis (tendonitis): Repeated use of the biceps or problems in the shoulder can irritate the proximal biceps tendon. Pain in the shoulder and biceps is the main symptom.
Biceps contracture: The biceps becomes permanently contracted, with the elbow bent. Biceps contracture may occur after a severe stroke.
Degenerative disease around shoulder joint- long head becomes frayed and weak - dislocated or torn
Torn muscle belly
6.7. Regarding the triceps .
6.7.1. Why its weakness and paralysis not of much clinical significance?
Because gravity will extend the elbow passively in most positions that the arm
assumes
6.7.2. Which group of patients will be most affected by its paralysis / weakness?
Those using crutches
6.8. What is compartment syndrome?
Compartment syndrome is a painful condition that occurs when the pressure within the muscles builds to dangerous levels. This pressure can decrease blood flow, which prevents nourishment and oxygen from reaching nerve and muscle cells. Compartment syndrome can be either acute or chronic.
6.8.1. What is the order in which key structures within the compartment are affected?
Compartment syndrome develops when swelling or bleeding occurs within a compartment.
Because the fascia does not stretch, this can cause increased pressure on the capillaries, nerves, and muscles in the compartment.
Blood flow to muscle and nerve cells is disrupted.
Without a steady supply of oxygen and nutrients, nerve and muscle cells can be damaged and necrosis occur.
6.8.2. What is their clinical significance?
Acute compartment syndrome is a medical emergency.
Can cause Volkmann’s contracture in affected limbs. Rhabdomyolysis (skeletal
muscle break down rapidly) and renal failure can occur.
6.9. Why is the suprascapular nerve liable to be injured.
The suprascapular nerve is particularly prone to injury at the suprascapular and spinoglenoid notches as the nerve is anatomically constrained at several points along its course, such as Distal to the suprascapular foramen, a posterior triangle of the neck and the supraclavicular region. Other reasons include the fractures of the superior lateral angle of the scapula,
with entrapment etc.
The nerve is held at both ends, has a long straight course & goes to a mobile structure
6.10. What is the clinical significance of the point where cephalic vein enter the axillary vein in the shoulder
Many patients who are critically unwell have lost blood or fluid, which requires replacement. Access to the peripheral vein is necessary to replace the fluid. The typical sites for venous access are the cephalic vein in the hand or veins that lie within the superficial tissue of the cubital fossa.
Can be readily exposed for emergency venous access
6.11. What are the two common types of brachial plexus injury and their causes?
Blunt trauma producing nerve avulsions and disruptions
Spinal cord injuries in the cervical region and direct pulling injuries affect the roots while severe trauma to the first rib usually affects the trunks. The division and cords of the brachial plexus can be injured by dislocation of the glenohumeral joint
Upper C5/6- erb’s palsy (shoulder dystocia in delivery, motorcycle injury, violent fall on head and shoulder
Lower C8/T1- Klumpke’s palsy (fall from a tree: grasping limb, motorbike injury)
6.11.1. What are the general effects of each injury type?
Upper- Mainly affects shoulder muscles
Lower- Affects hand muscles
6.11.2. What is the clinical appearance in an Erb-Duchenne paralysis?
6.11.2.1. Explain how this limb position is attained
Waiter’s tip: paralysis of deltoid and short muscle, arm limp by side, paralysis of
biceps and brachialis- the absence of flexion and supination of elbow
6.11.3. Briefly explain how to obtain brachial plexus nerve block?
Because the axillary sheath encloses the axillary vessels and the brachial plexus, a
brachial plexus nerve block can easily be obtained. The distal part of the sheath is closed
with finger pressure, and a syringe needle is inserted into the proximal part of the sheath.
The anesthetic solution is then injected into the sheath, and the solution is massaged
along the sheath to produce the nerve block. The position of the sheath can be verified by
feeling the pulsations of the 3rd part of the axillary artery.
6.12. Explain the following effects of AXILLARY NERVE involvement:
6.12.1. Loss of weakness of shoulder abduction between 15o -90o
Deltoid paralysed but supraspinatus which initiates abduction is intact
6.12.2. Loss of rounded contour of the shoulder
6.12.3. ‘Regimental badge’ sensory loss
6.13. Explain the physical appearance of a patient with LONG THORACIC NERVE INJURY
6.14. Explain the following effects of SUPRASCAPULAR NERVE entrapment
6.14.1. Typical dull posterior and lateral shoulder pain
6.14.2. Tenderness 2.5cm lateral to the midpoint of the scapular spine
Site of suprascapular notch
6.14.3. Weakness of shoulder abduction and external rotation
Involvement of supraspinatus and infraspinatus
6.15. The RADIAL NERVE can commonly be affected by injury (1)of the nerve roots of the brachial plexus (2) in the radial groove.
6.15.1. How will you distinguish this condition from lesions affecting the nerve roots of the
brachial plexus?
Loss of triceps function reflects an injury at the brachial plexus
If the brachioradialis or extensor carpi radialis longus are not functional, then the injury is
most likely at the level of humeral shaft
6.16. Explain the following motor effects of a high lesion of the radial nerve at the axilla (crutch
paralysis)
Loss of extension of supinated elbow
Loss of extension of wrist (wrist drop)
Motor deficit:- paralysis of triceps and extensors of forearm
Wrist drop, loss of wrist and finger extension. Radial nerve injuries result in a decrease in power grip and pinch related to loss of wrist extension. Paralysis of extensors wrist and unopposed action of flexors of wrist
6.17. Map the sensory loss produced in a Radial N. injury at the axilla
Loss of pin prick and light touch over post surface of lower arm and narrow strip over back of forearm, dorsum of 1st, 2nd and 3rd metacarpals and corresponding proximal and middle phalanges
6.17.1. What is a “Saturday night palsy” ?
This neuropathy is produced by compression of the radial nerve as it spirals around the humerus.
Palsy resulting from pressure after sleeping with arm over chair or hard object
6.18. Explain how one is able to extend his elbow in a lesion of the Radial N. in the radial groove (Saturday night paralysis).
Long and medial head of triceps (the chief extensors of the elbow) are supplied by radial nerve in the axilla
6.19. How would the effects of injury to the deep branch of the Radial N (post. Interosseous N.) be different from that of injury in the radial groove? .
The effects are the same as in the injury at the radial groove except that no or little wrist drop occurs due to sparing of the brachioradialis and wrist extensors.
7. RADIOLOGY
7.1. Describe a normal mammogram
Normal breast tissue contains fats as well as with glandular and fibrous tissue. The more fibroglandular tissue present in the breast, the denser the breasts are. Even though the breasts are dense, it doesn’t mean it is a positive chance of malignancy.
E.g of what still a normal breast looks like
The description for each image orderly, almost entirely fatty scattered areas of fibroglandular density heterogeneously dense extremely dense
1
No abnormalities were detected.
2
Results may be negative for cancer, but will be used for comparison for future mammograms.
3
Findings are probably benign. You may need a follow-up mammogram in 6 months.
4
An abnormality was found, but doesn’t appear cancerous. You may need a biopsy.
Study the following :
7.2. Humerus : AP and Lateral views (ANM Upper Limb Radiology 48)
AP(anteroposterior)
AP view of the humerus is part of the humerus series and is usually taken in standing position. However, it can also be obtained in a supine position.
Lateral view
7.3. Fracture shaft of humerus
Can be open or close (open more prone to infection)
occur as a result of a direct blow to the upper arm (transverse fractures). Indirect trauma from a fall or a twisting action (e.g. arm wrestling) are also encountered and usually result in spiral or oblique fractures
7.4. Fracture upper end of humerus
Surgical neck fracture
Intercondylar fracture of humerus
Avulsion of greater tubercle
7.5. Arteriogram of the Axillary artery and its branches
6.5.1.1. What neurovascular structures may be injured and what is the clinical importance? Radial (most common)/ulnar/median nerve damage, up to 90% of patients with a closed humeral fracture with radial nerve injury will have a resolution of neuropraxia within three to four months following the injury.
Radial nerve, profunda brachii artery & vein
Large haematoma, muscle necrosis, compartment syndrome, peripheral ischaemia due to swelling, radial nerve palsy (wrist drop & sensory loss)
6.6. Regarding the biceps.
6.6.1.1. Why is it commonly injured?
Involved in many actions Crosses 2 joints (compare to hamstrings in the thigh)
6.6.1.2. Name 2 clinical conditions of biceps.
Proximal biceps tendinitis (tendonitis): Repeated use of the biceps or problems in the shoulder can irritate the proximal biceps tendon. Pain in the shoulder and biceps is the main symptom.
Biceps contracture: The biceps becomes permanently contracted, with the elbow bent. Biceps contracture may occur after a severe stroke.
Degenerative disease around shoulder joint- long head becomes frayed and weak - dislocated or torn
Torn muscle belly
6.7. Regarding the triceps .
6.7.1. Why its weakness and paralysis not of much clinical significance?
Because gravity will extend the elbow passively in most positions that the arm
assumes
6.7.2. Which group of patients will be most affected by its paralysis / weakness?
Those using crutches
6.8. What is compartment syndrome?
Compartment syndrome is a painful condition that occurs when the pressure within the muscles builds to dangerous levels. This pressure can decrease blood flow, which prevents nourishment and oxygen from reaching nerve and muscle cells. Compartment syndrome can be either acute or chronic.
6.8.1. What is the order in which key structures within the compartment are affected?
Compartment syndrome develops when swelling or bleeding occurs within a compartment.
Because the fascia does not stretch, this can cause increased pressure on the capillaries, nerves, and muscles in the compartment.
Blood flow to muscle and nerve cells is disrupted.
Without a steady supply of oxygen and nutrients, nerve and muscle cells can be damaged and necrosis occur.
6.8.2. What is their clinical significance?
Acute compartment syndrome is a medical emergency.
Can cause Volkmann’s contracture in affected limbs. Rhabdomyolysis (skeletal
muscle break down rapidly) and renal failure can occur.
6.9. Why is the suprascapular nerve liable to be injured.
The suprascapular nerve is particularly prone to injury at the suprascapular and spinoglenoid notches as the nerve is anatomically constrained at several points along its course, such as Distal to the suprascapular foramen, a posterior triangle of the neck and the supraclavicular region. Other reasons include the fractures of the superior lateral angle of the scapula,
with entrapment etc.
The nerve is held at both ends, has a long straight course & goes to a mobile structure
6.10. What is the clinical significance of the point where cephalic vein enter the axillary vein in the shoulder
Many patients who are critically unwell have lost blood or fluid, which requires replacement. Access to the peripheral vein is necessary to replace the fluid. The typical sites for venous access are the cephalic vein in the hand or veins that lie within the superficial tissue of the cubital fossa.
Can be readily exposed for emergency venous access
6.11. What are the two common types of brachial plexus injury and their causes?
Blunt trauma producing nerve avulsions and disruptions
Spinal cord injuries in the cervical region and direct pulling injuries affect the roots while severe trauma to the first rib usually affects the trunks. The division and cords of the brachial plexus can be injured by dislocation of the glenohumeral joint
Upper C5/6- erb’s palsy (shoulder dystocia in delivery, motorcycle injury, violent fall on head and shoulder
Lower C8/T1- Klumpke’s palsy (fall from a tree: grasping limb, motorbike injury)
6.11.1. What are the general effects of each injury type?
Upper- Mainly affects shoulder muscles
Lower- Affects hand muscles
6.11.2. What is the clinical appearance in an Erb-Duchenne paralysis?
6.11.2.1. Explain how this limb position is attained
Waiter’s tip: paralysis of deltoid and short muscle, arm limp by side, paralysis of
biceps and brachialis- the absence of flexion and supination of elbow
6.11.3. Briefly explain how to obtain brachial plexus nerve block?
Because the axillary sheath encloses the axillary vessels and the brachial plexus, a
brachial plexus nerve block can easily be obtained. The distal part of the sheath is closed
with finger pressure, and a syringe needle is inserted into the proximal part of the sheath.
The anesthetic solution is then injected into the sheath, and the solution is massaged
along the sheath to produce the nerve block. The position of the sheath can be verified by
feeling the pulsations of the 3rd part of the axillary artery.
6.12. Explain the following effects of AXILLARY NERVE involvement:
6.12.1. Loss of weakness of shoulder abduction between 15o -90o
Deltoid paralysed but supraspinatus which initiates abduction is intact
6.12.2. Loss of rounded contour of the shoulder
6.12.3. ‘Regimental badge’ sensory loss
6.13. Explain the physical appearance of a patient with LONG THORACIC NERVE INJURY
6.14. Explain the following effects of SUPRASCAPULAR NERVE entrapment
6.14.1. Typical dull posterior and lateral shoulder pain
6.14.2. Tenderness 2.5cm lateral to the midpoint of the scapular spine
Site of suprascapular notch
6.14.3. Weakness of shoulder abduction and external rotation
Involvement of supraspinatus and infraspinatus
6.15. The RADIAL NERVE can commonly be affected by injury (1)of the nerve roots of the brachial plexus (2) in the radial groove.
6.15.1. How will you distinguish this condition from lesions affecting the nerve roots of the
brachial plexus?
Loss of triceps function reflects an injury at the brachial plexus
If the brachioradialis or extensor carpi radialis longus are not functional, then the injury is
most likely at the level of humeral shaft
6.16. Explain the following motor effects of a high lesion of the radial nerve at the axilla (crutch
paralysis)
Loss of extension of supinated elbow
Loss of extension of wrist (wrist drop)
Motor deficit:- paralysis of triceps and extensors of forearm
Wrist drop, loss of wrist and finger extension. Radial nerve injuries result in a decrease in power grip and pinch related to loss of wrist extension. Paralysis of extensors wrist and unopposed action of flexors of wrist
6.17. Map the sensory loss produced in a Radial N. injury at the axilla
Loss of pin prick and light touch over post surface of lower arm and narrow strip over back of forearm, dorsum of 1st, 2nd and 3rd metacarpals and corresponding proximal and middle phalanges
6.17.1. What is a “Saturday night palsy” ?
This neuropathy is produced by compression of the radial nerve as it spirals around the humerus.
Palsy resulting from pressure after sleeping with arm over chair or hard object
6.18. Explain how one is able to extend his elbow in a lesion of the Radial N. in the radial groove (Saturday night paralysis).
Long and medial head of triceps (the chief extensors of the elbow) are supplied by radial nerve in the axilla
6.19. How would the effects of injury to the deep branch of the Radial N (post. Interosseous N.) be different from that of injury in the radial groove? .
The effects are the same as in the injury at the radial groove except that no or little wrist drop occurs due to sparing of the brachioradialis and wrist extensors.
7. RADIOLOGY
7.1. Describe a normal mammogram
Normal breast tissue contains fats as well as with glandular and fibrous tissue. The more fibroglandular tissue present in the breast, the denser the breasts are. Even though the breasts are dense, it doesn’t mean it is a positive chance of malignancy.
E.g of what still a normal breast looks like
The description for each image orderly, almost entirely fatty scattered areas of fibroglandular density heterogeneously dense extremely dense
1
No abnormalities were detected.
2
Results may be negative for cancer, but will be used for comparison for future mammograms.
3
Findings are probably benign. You may need a follow-up mammogram in 6 months.
4
An abnormality was found, but doesn’t appear cancerous. You may need a biopsy.
Study the following :
7.2. Humerus : AP and Lateral views (ANM Upper Limb Radiology 48)
AP(anteroposterior)
AP view of the humerus is part of the humerus series and is usually taken in standing position. However, it can also be obtained in a supine position.
Lateral view
7.3. Fracture shaft of humerus
Can be open or close (open more prone to infection)
occur as a result of a direct blow to the upper arm (transverse fractures). Indirect trauma from a fall or a twisting action (e.g. arm wrestling) are also encountered and usually result in spiral or oblique fractures
7.4. Fracture upper end of humerus
Surgical neck fracture
Intercondylar fracture of humerus
Avulsion of greater tubercle
7.5. Arteriogram of the Axillary artery and its branches
Pectoral Girdle & Shoulder
BONES
1.1. Identify the components of the pectoral girdle
Clavicle and scapula
1.2. Demonstrate how you would hold the clavicle in anatomical position.
In posterior position, sternal end on the left and acromial end on the right. Corocoid tubercle and costal tuberosity at inferior surface
1.2.1. How is the clavicle different from other long bones in its ossification
Intramembranous ossification, even though it is a long bone. Other long bone ossify endochondrally.
1.2.2. Explain why the conoid tubercle & trapezoid line are important (http://www.getbodysmart.com/ap2/skeletalsystem/skeleton/appendicular/upperlimbs/clavicle/tutorial.html)
Conoid Tubercle: provide attachment for conoid ligament, provides landmark of inferior of clavicle
Trapezoid line: provide attachment for trapezoid ligament
Ans: the 2 parts of the coracoclavicular ligament are attached (the accessory ligament that gives the acromioclavicular joint its strength)
1.2.3. Identify where the major muscles are attached to the clavicle
Posterior side of the clavicle - supraspinous fossa, infraspinous fossa
Anterior side - clavicular fossa
Ans: pectoralis major, deltoid (anterior surace lateral third and periosteum), sternomastoid, trapezius (posterior surgface lateral third), subclavius (inferior surface)
1.3. Identify the scapula and describe how to hold it in anatomical position
http://www.getbodysmart.com/ap/skeletalsystem/skeleton/appendicular/upperlimbs/scapula1/tutorial.html
On an anterior point of view, the medial end is facing the medial region of our body , coracoid process, glenoid cavity is lateral to our vertebrae.
1.3.1. Identify the coracoid process of the scapula.
Inferior to acromion process , lateral to humerus
1.3.1.1. List the structures attached to the coracoid process of the scapula.
Ans: Coracobrachialis, short head of biceps, pectoralis minor, coracohumeral ligament, coracoacromial ligament, coracoclavicular ligament
1.3.2. Identify the scapula angles & medial border
Superior, lateral and inferior angle.
Medial border: Vertebral border
1.3.2.1. On which ribs are the superior & inferior angles related?
T2 - T7
1.3.2.2. Which muscles are attached to the medial border?
Serratus anterior, rhomboid minor and major, levator scapulae, small part of latissimus dorsi
1.3.3. Identify the scapular spine and the fossae related to it
Spine is sandwiched in between supraspinous and infraspinous fossa
1.3.3.1. Trace and identify the landmark at its lateral end.
Glenoid cavity , coracoid process, acromion process
1.4. Identify head, greater and lesser tubercles in the upper end of the humerus.
The lesser tubercle is at the anatomical anterior side of humerus, greater is at posterior, head of humerus is in glenoid cavity
1.4.1. Identify the bicipital groove. What muscles are attached to it?
Slender tendon of long head of bicep muscle, pectoralis major to the lateral lip, teres major to the medial lip and latissimus dorsi to the floor
Ans: pectoralis major to lateral lip; teres major to medial lip; latissimus dorsi to the floor
1.4.2. Outline the anatomical and surgical necks of the humerus on the bone.
Anatomical neck is near the head of humerus
Surgical neck is a constriction below the tubercles of the greater tubercle and lesser tubercle, and above the deltoid tuberosity
1.4.3. What are the key relations of the surgical neck?
Easily fractured compared to anatomical neck, more surgery needed.
MUSCLES
2.1. Do a virtual dissection in 4 D Anatomy (http://4danatomy.com/modules ) to explore the shoulder region : Left Shoulder (upper Lateral View)
2.2. Identify the following muscles around the pectoral girdle: (ANM Upperlimb System 19)
Pectoralis major and minor, Trapezius,Serratus anterior, Rhomboids major and minor, Teres major and minor, Biceps, Coracobrachialis, Triceps
2.3. Explain their actions by their attachments
http://www.getbodysmart.com/ap/muscularsystem/armmuscles/menu/menu.html
2.4. Identify deltoid and its proximal and distal attachments.
Attachments
Origin: (proximal attachments)
Anterior (clavicular) head: upper anterior surface of the lateral ⅓ of clavicle.
Middle (acromial) head: lateral acromion process and spine of the scapula
Insertion: (distal attachments)
Deltoid tuberosity of the humerus
2.5. Explain its actions
http://www.getbodysmart.com/ap2/muscularsystem/armmuscles/anteriormuscles/deltoid/tutorial.html
Flex the arm at the shoulder joint
Medially rotates the arm at the shoulder joint
Abducts the arm at the shoulder joint
Extend arm and rotate laterally
Centre of the triangle: base formed by the lower edge of acromial process and apex by the insertion of the deltoid
Deltoid muscles are well developed in adults and easily accessible, no major vessels
2.6. Identify the rotator cuff muscles.
Teres minor, supraspinatus, infraspinatus, subscapularis
Attached to the greater tuberosity and lesser tuberosity
2.6.1. What are their attachments and actions?
http://www.getbodysmart.com/ap/muscularsystem/armmuscles/menu/menu.html
Subscapularis-
helps to stabilize the head of the humerus in the glenoid fossa during shoulder movements.
Origin: (proximal attachments)
Subscapular fossa of the scapula.
Insertion: (distal attachments)
Lesser tubercle of humerus.
Action: Medially rotates the arm at the shoulder (glenohumeral) joint
Supraspinatus
Origin: (proximal attachments)
Supraspinous fossa of the scapula.
Insertion: (distal attachments)
Superior aspect of the greater tubercle of the humerus.
passes under acromion to attach to the superior of greater tubercle
Actions- Helps the deltoid muscle initiate the abduction of the arm at the shoulder (glenohumeral) joint., Helps stabilize the shoulder by drawing the humerus toward the glenoid fossa of the scapula.
Infraspinatus
provides the mechanical link between the posterosuperior and anterior parts of the rotator cuff.
Origin: (proximal attachments)
Infraspinous fossa of the scapula.
Insertion: (distal attachments)
Middle part of the greater tubercle of the humerus.
Actions- laterally rotates the arm at the shoulder (glenohumeral) joint, Helps stabilize the shoulder by drawing the humerus toward the glenoid fossa of the scapula.
Teres minor
It’s narrow and elongated in shape and sometimes may be fused with infraspinatus. Its main function is to stabilize the humerus in the glenoid fossa when the shoulder moves.
Origin: (proximal attachment)
a. Middle part of the lateral (axillary) border of the scapula.
Insertion: (distal attachment)
a. Inferior aspect of greater tubercle of humerus.
Actions- laterally rotates the arm at the shoulder joint, weakly adducts the arm at the shoulder joint, Helps stabilize the shoulder by drawing the humerus toward the glenoid fossa of the scapula.
2.7. What is a bursa? List the bursae around the shoulder joint.
Subacromial bursae, subdeltoid bursae, subcoracoid bursae, subscapular bursae
Bursa- small fluid-filled sac lined by synovial membrane with an inner capillary layer of viscous synovial fluid (similar in consistency to that of a raw egg white) which provides a cushion between bones and tendons/ muscles around a joint
2.7.1. Identify the subacromial bursa
2.7.1.1. What is its function?
Facilitate the gliding of muscles or tendons over bony or ligamentous surfaces
Facilitates the movements of the deltoid over the fibrous capsule of the shoulder joint and the supraspinatus tendon
2.8. Identify the muscles which move the scapula (ANM Upperlimb System 21)
2.8.1. Demonstrate on each other (your peers) the range of movements possible involving the scapula.
Protraction: scapula moves forwards on the chest wall (punching and reaching forward), Retraction: scapula are drawn backwards in the direction of the median plane in bracing back of the shoulders, Elevation: the scapula is elevated (shrugging)
2.8.2. List briefly the actions of the principal muscles that move the scapula
Ans: Elevation: simultaneous contraction fo the levator scapulae and the upper fibres of the trapezius
Depression: simultaneous contraction of the pectoralis minor, lower fibres of trapezius and latissimus dorsi
Medial: simultaneous contraction of levator scapulae, rhomboids, and latissimus dorsi. The gravity (weight of the upper limb) plays a key role in this movement
Lateral: trapezius and serratus anterior. The glenoid cavity is tilted upwards which is necessary for the abduction of the upper limb above 90 degrees.
Protraction: serratus anterior assisted by the pectoralis minor muscle
Retraction: middle fibres of the trapezius and rhomboids
2.9. Identify and define the boundaries of the quadrangular space. (ANM Upperlimb Regions 12,22)
Ans: superior (above): teres minor posteriorly, inferior (below): teres major, medially: the long head of the triceps branchii, laterally: the surgical neck of the humerus, anteriorly: the subscapularis
2.9.1. What are its contents?
Ans: it transmits the axillary nerve and posterior circumflex humeral vessels (artert and vein)
Axillary nerve, posterior circumflex humeral artery
2.10. Identify and define the boundaries of the triangular space. (ANM Upperlimb Regions 23)
Ans: inferior: the superior border of the teres major, lateral: the long head of the triceps, superios: teres minor or subscapularis
2.10.1. What are its contents?
Circumflex scapular artery
2.10.2. Where does the circumflex scapular artery arise and along with which
other artery?
From the subscapular artery; thoracodorsal artery
2.10.3. Which muscle does that latter artery mainly supply?
Latissimus dorsi
3. JOINTS
3.1. Identify the articulating surfaces of the shoulder joint. (ANM Upperlimb System 11)
3.1.1. Identify the Fibrous capsule of shoulder joint and its thickenings.
Fibrous joint capsule surrounds the glenohumeral joint and is
attached medially to the margin of the glenoid cavity and laterally to the
anatomical neck of the humerus. The intrinsic ligaments are the
thickenings of the fibrous capsule, which strengthen the shoulder
joint.
3.1.1.1. Where is it lax?
The capsule is lax and lies in folds when the arm is adducted
3.2. Identify the Ligaments around the shoulder joint (ANM Upperlimb System 11)
3.2.1. Identify the ligament which reinforces the fibrous capsule.
Coracohumeral ligament
3.2.2. Identify the ligament, located above the joint, that forms a special
structure?
The coracoacromial ligament attaches by its base to the lateral border of the
coracoid process and by its apex to the medial border of the acromion. It
forms coracoacromial arch (coracoid process+coracoacromial ligament +
acromion = coracoacromial arch) above the capsule of the
shoulder joints. It prevents superior displacement of the head of the humerus.
3.2.3. Identify ligament is located below the joint. What is its significance?
Transverse humeral ligament, it converts the groove into canal, which holds
the synovial sheath and tendon of the biceps brachii in place during
movements of the glenohumeral joint.
The transverse humeral ligament attaches to the margins of the bicipital
groove preventing displacement of the tendon of long head of biceps. It forms
the roof of a fibro-osseous tunnel, where the tendon of long head of biceps
can become irritated by friction, resulting in bicipital tendonitis.
http://www.orthosurgery.gr/parousiasis/shoulder/119.pdf
3.3. Draw a table listing the principal movements of the shoulder joint and the important muscles involved in these movements.
Movement
Prime Mover
Synergist
Flexion
Pectoralis major (clavicular head), deltoid (clavicular and anterior acromial parts)
Coracobrachialis (assisted by biceps brachii
Extension
Deltoid (spinal part)
Teres major, latissimus dorsi, long head of triceps brachii
Abduction
Deltoid (as a whole, but especially acromial part)
Supraspinatus
Adduction
Pectoralis major, latissimus dorsi
Teres major, long head of triceps brachii
Medial Rotation
Subscapularis
Pectoralis major, deltoid (clavicular part), latissimus dorsi, teres major
Lateral rotation
Infraspinatus
Teres minor, deltoid (spinal part)
Tensors of articular capsule (to hold head of humerus against the glenoid cavity)
Subscapularis, infraspinatus
Supraspinatus, teres minor
Resisting down-ward dislocation (shunt muscles)
Deltoid
Long head of triceps brachii, coracobrachialis, short head of biceps brachii
3.4. Demonstrate using a volunteer how you will test the movements of the shoulder joint both actively and passively.
3.5. Why is the shoulder joint the commonest joint to dislocate? (anterior dislocation - most common)
The shoulder joint has a shallow socket. The smaller glenoid cavity in comparison with the larger head of humerus causes a lot of instability in the joint.
3.5.1. Explain the factors involved in maintaining joint stability and their relative importance:
Bony articulating surfaces
The glenohumeral joint is the main articulation of the shoulder joint. It
is the multiaxial ball-and-socket synovial joint formed by the articular
surfaces of the glenoid cavity and the head of the humerus. The
glenoid cavity depth is increased by a rim of fibrocartilage that
surrounds it which increases the stability of the joint
Joint capsule & ligaments
The joint capsule at the shoulder is formed by a group of ligaments
that connect the humerus to the glenoid. These ligaments are the
main source of stability for the shoulder. They are the superior, middle
and inferior glenohumeral ligaments, coracohumeral ligaments and
transverse humeral ligaments
http://www.radiologyassistant.nl/en/p4f49ef79818c2/shoulder-mr-anatomy.html
key muscles (rotator cuff)
Your rotator cuff is made up of muscles and tendons that keep the ball
(head) of your upper-arm bone (humerus) in your shoulder socket. It
also helps you raise and rotate your arm. They consist of the
supraspinatus, infraspinatus, teres minor and subscapularis
3.6. Which is the only articulation between the upper limb and axial skeleton? (ANM Upperlimb System 10)
The sternoclavicular joint
3.6.1. How is this joint divided?
Medial and lateral compartments by and intra-articular fibrocartilaginous disc
Articular disc
3.6.2. How is this joint made extremely strong?
Due to the multiple ligaments that hold the joint together such as the costoclavicular ligaments, the intra-articular disc ligament, the interclavicular ligament and the capsular ligament that surrounds the joint
Anterior and posterior sternoclavicular ligament, interclavicular ligament
3.7. What special structure is found in the AC(Acromioclavicular) joint and what is its function? (ANM Upperlimb System 10)
Atypical synovial joint made up of fibrocartilage (articular disc), absorb shock and reduce friction during movement (for articulation too) -> allows anterior and posterior movement of the acromion, rotation & tilting of the acromion
A fibrocartilaginous disc (partial) which divides the join in two, allowing two different movements
3.7.1. Define an intrinsic ligament and identify the intrinsic ligament of the AC joint
Intrinsic ligaments - surround the joint; may be extracapsular(outside capsule)
or intracapsular (inside capsule) - acromioclavicular ligament
A ligament that is a capsular thickening: the acromioclavicular ligament
3.7.2. Define an accessory ligament and identify the the accessory ligament of
the AC joint
Separate ligaments or parts of the joint capsule serve as support strengthens
or supports the primary ligament - Coracoclavicular Ligaments (Conoid and
Trapezoid ligament)
A ligament distant to the joint that gives it stability: coracoclavicular ligament
3.8. Identify the following ligaments and give their functions
3.8.1. coracohumeral ligament.
It attaches to the lateral part of the base of the coracoid process and crosses
the shoulder joint to attach to the anterior surface of the greater tubercle of the
humerus, where it blends with the fibrous capsule of the shoulder and the
tendon of the supraspinatus.
Carries the dead weight of the arm
3.8.2. coracoacromial ligament.
CAL also acts to transmit loads across the scapula. Serving as a tension
band, forces exerted on the coracoid process by the coracobrachialis,
pectoralis minor, and biceps (short head) muscles are transmitted to the
acromion; attaches the coracoid process with the acromion process
Arches over the shoulder joint, helping to prevent superior dislocation and
stabilize the supraspinatus
3.8.3. transverse humeral ligament.
Holds the tendon of the long head of biceps brachii muscle in the groove
between the greater and lesser tubercle on the humerus (intertubercular
sulcus)
Holds long head biceps in bicipital groove (between the tuberosities)
3.8.3.1. What happens if this is ruptured?
Indicate a moderate to severe shoulder separation, affects the stability
of AC joint, pain, range of movements will be impaired
Subluxed, dislocated or prolapsing long head of biceps
4. CLINICAL/SURFACE ANATOMY
4.1. Palpate and demonstrate on your willing and consenting peers the following:
4.1.1. Subcutaneous borders of the clavicle (concavity and convexity)
4.1.1.1. Sternal end (with sternum & 1st costal cartilage forming sternoclavicular jt)
4.1.1.2. Acromial end(Flattened at the top; with Acromion forming acromioclavicular jt)
4.1.2. Scapula:
4.1.2.1. Vertebral levels ( of medial end of Spine, Inf angle)
T2/3- T7
4.1.2.2. Acromion process
4.1.2.3. Apex of acromion ( lat. to and in front of acromial end of clavicle)
4.1.2.4. Acromial angle (change of direction of post inf. border of the acromion),
4.1.2.4.1. How is the length of the arm measured clinically?
Acromial angle to lateral condyle
4.1.3. Spine 4.1.4. Coracoid Process( just medial to humeral head and below the clavicle)
4.1.5. Humerus:
4.1.5.1. Greater tubercle
4.1.5.2. Lesser tubercle
4.1.6. Deltoid muscle
4.1.6.1. Posterior ( spinous ) fibres : Subject’s arm 90o abducted; apply resistance to the post and inferior aspect of arm. Feel the post bundle at the post aspect of shoulder
4.1.6.2. Anterior ( clavicular) fibres: Subject’s arm 90o abducted, elbow flexed. Ask the subject perform horizontal flexion of the shoulder which you resist to palpate the ant bundle
4.2. Study the following procedures and explain its anatomical basis:
4.2.1. Subacromial injection (ANM Upperlimb Dissection 54)
4.2.2. Locate the exact site of deltoid IM injection and explain why such a site
is chosen. (ANM Upperlimb Dissection 53)
4.3. Regarding the clavicle:
4.3.1. What is a fracture of a bone?
A fracture is a broken bone. It can range from a thin crack to a complete break.
4.3.2. Why and where is the most common site of clavicular fracture?
Between the middle (⅔) and the lateral third (⅓) of the clavicle because it’s the weakest part of clavicle (changing from convex to concave & changing in shape[circular and flattened])
Junction of medial ⅔ of shaft and lateral ⅓. A long bone fractures at its site of greatest change in curvature, change of cross section; supraclavicular nerves pierce
4.3.2.1. What structures are at risk with a fractured clavicle?
Brachial plexus trunks & divisions, subclavian vessels, supraclavicular nerves; skin
and associated chest injuries such as 'pneumothorax or hemothorax
4.3.2.2. Explain how the muscles attached to the clavicle are
displaced in the fracture
4.3.2.3. How will the patient present with a fractured clavicle and
explain why he assumes this characteristic posture?
Shoulder drops:The trapezius muscle is unable to hold the lateral fragment up owing to the weight of the upper limb; supporting sagging upper limb with opposite hand.
Prominent superiorly directed clavicle fragment(medial)[easily be palpated, and frequently seen]: Sternocleidomastoid muscle elevates the medial fragment of bone and clavicle is at subcutaneous position
A man supporting his sagging upper limb with his opposite hand- trapezius (by which the arm hangs) unable to support arm drawn medially by the adductors- teres major and pectoralis major
4.4 Regarding the scapula:
4.4.1. Explain the cause of Dropped shoulder and Winged scapula.
Position of scapula on posterior wall of thorax is maintained by tone and balance of the muscles attached to it. If one of these muscles is paralyzed, the balance is upset, as in dropping of the shoulder, which occurs with paralysis of the trapezius or winged scapula, caused by paralysis of the serratus anterior
Causes:
Loss of Serratus Anterior muscle function
The traumatic injury to the nerve supplying the serratus anterior muscle (the long thoracic nerve), or due to the pressure lesions or neuritis(inflammation of the nerve) which damage the nerve. The long thoracic nerve is vulnerable to injury than other nerves of the brachial plexus.
To test if it is the long thoracic nerve injury is by the serratus wall test; patient stand from the wall and then pushed against the wall with flat palms at waist level.
2. Loss of trapezius muscle function
It is may be the result of radical neck surgery (tumours) where the spinal accessory nerve which supplies the trapezius muscle is damaged.
3. Weakness of all scapula stabilisers
Muscular dystrophies (commonly known as FSHD FacioScapuloHumeral Dystrophy) are the culprit for weakness of all scapula stabilizing muscles
4. Loss of scapular suspensory mechanism
Since the acromioclavicular(AC) joint is the only joint that connects the scapula to the rest of the body. Thus, dislocation of the AC joint or the fracture of the outer third clavicle, with the rupture of coracoclavicular ligaments lead to an abnormal scapular rhythm
5. Winging of the scapula secondary to instability
Recurrent dislocations of the shoulder leads to dysfunction of the muscles that move and support the shoulder complex and scapula. The more dislocations, the worse the scapula dysrhythmia (winging).
6. Winging secondary to pain
Shoulder pain can cause abnormal movements of the entire shoulder complex. Therefore, reduced movements of the glenohumeral joint will lead to more compensatory movements by the scapula
7. Brachial Plexus injury or disease
Major accidents to the brachial plexus or Parsonage-Turner syndrome (Brachial neuritis) are causes to weakness of scapular muscles.
https://www.shoulderdoc.co.uk/section/492
4.5. Regarding bursa:
4.5.1. How is “painful arc syndrome” caused ?
Tear/ inflammatory degeneration or calcified deposit in supraspinatus tendon
Subacromial bursitis
Painful arc syndrome is also called supraspinatous tendonitis (inflamed tendon) mainly due to friction between supracromial tendon and acromion
Causation
bony structures such as subacromial spurs (bony projections from the acromion)
osteoarthritic spurs on the acromioclavicular joint
variations in the shape of the acromion
Thickening or calcification of the coracoacromial ligament can also cause impingement
Loss of function of the rotator cuff muscles, due to injury or loss of strength, may cause the humerus to move superiorly, resulting in impingement
Inflammation and subsequent thickening of the subacromial bursa (bursitis) may also cause impingement.
Weight training exercises where the arms are elevated above shoulder height but in an internally rotated position such as the upright row have been suggested as a cause of subacromial impingement.
-may also be due to subacromial bursitis
-may also be due to tendon tear or tendonitis because as abduction is conducted, the tendon impinge under the acromion
-usually in shoulder examination - angle of 60 - 120 degrees will induce the pain
4.5.2. Explain why pain occurs in mid-range of abduction.
Pain in mid range between 60 to 120 degrees of abduction
There is no pain in adduction because the inflamed bursa is away from the
acromion, but in abduction the supraspinatus tendon comes in contact with
the inferior surface of the acromion. Further the inflamed bursa slips
underneath the coracoacromial arch and gets impinged between the
supraspinatus and acromion.
4.6. Regarding shoulder joint:
4.6.1. What is the effect of prolonged immobilization of the joint?
Musculoskeletal complications include loss of muscle strength and
endurance, contractures and soft tissue changes, disuse osteoporosis, and degenerative joint disease.
The fibrous capsule tightens with inactivity and old age. The shoulder joint is vulnerable to immobilisation, particularly in the elderly and in diabetics, resulting in a ‘frozen shoulder’ (periarticular adhesions) with painful restriction of movement leading to further immobilisation (leading to even more fibrosis)
4.6.2. Define dislocation of a joint.
A joint dislocation, also called luxation, occurs when there is an
abnormal separation in the joint, where two or more bones meet. A partial dislocation is referred to as a subluxation
4.6.3. Which nerve(s) are commonly injury in relation to injuries of the shoulder joint?
Axillary nerve
4.6.3.1. How will you proceed to test such a nerve damage (clinical features)?
Inspection- squaring of the shoulder as the normal countour of the shoulder is lost
Sensory- regimental badge area
Motor- deltoid
4.6.4. Explain the anatomical basis of characteristic appearance of the dislocated shoulder joint on inspection.
Head of humerus held adducted by shoulder girdle muscles and internally rotated by subscapularis; loss of roundess of shoulder by downward displacement of greater tubercle
4.6.5. What is reduction of a dislocation?
Skilled manipulation to return bones to their normal position
4.6.5.1. Describe which movements of the humeral head is encouraged
(the anatomical basis) for reduction of the anterior dislocation of the
Shoulder
Each reduction method works by abduction and external rotation to
disengage the humeral head from the glenoid, with axial traction to
reduce it
4.6.5.2. How such principles of reduction is applied through the
Traction-countertraction method?
Traction-countertraction
The patient is placed supine (lie on the back) with the bed elevated. A
sheet is looped around the axilla with one free end on the chest and the
other underneath the back. The 2 ends should be of even length. An
assistant uses these free ends to apply countertraction. Then the
practitioner abducts the arm to 90 degrees and flexed the elbow to 90
degrees. With the forearm, slow longitudinal traction is then applied to
the affected extremity.
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