MSK Anatomy: Axilla, Cubital Fossa, Joints, Brachial Plexus

MSK 1 Anatomy A. Spaces: 1: Enumerate Contents of axilla? Vessels: 1- Axillary artery & its branches. 2- Axillary vein & its tributaries. Nerves: 1- Cords & branches of the brachial plexus (infraclavicular part). Lymph nodes: Axillary lymph nodes. Special contents: 1- Axillary tail of the breast. 2- Axillary sheath: It contains axillary vessels & brachial plexus. 2. Mention the contents of cubital fossa Medially: 1- Median nerve: it leaves the cubital fossa by passing between the two heads of pronator teres muscle Laterally: 2- Radial nerve and its two terminal branches: a. Posterior interosseous nerve: leaves the fossa by passing between the Gehad Sayed MSK 1 two heads of supinator. b. Superficial radial nerve: leaves the fossa under cover of brachioradialis. In the Middle: Termination of the brachial artery and the beginning of ulnar and radial arteries 3. Brachial artery lies in the middle of the cubital fossa a. UInar artery leaves the cubital fossa by passing deep to the two heads of pronator teres b. Radial artery leaves the cubital fossa by descending through .the apex 4. Tendon of biceps: inserted into the posterior part of radial .tuberosity b. Joints Shoulder joint Enumerate Types of shoulder ligaments? 1)Coracohumeral. 2)Glenohumeral 3)Transverse humeral 4)Coracoacuromial Enumerate ligaments of the Shoulder joint Gehad Sayed MSK 1 A) Extracapsular ligaments : Coraco-humoral ligament B) Intracapsular ligaments : 1- Gleno-humeral ligaments: they are 3 bands 2- Transvesrse humeral ligament Explain why The shoulder joint is weak and unstable due to: 1:Bony factors: Poor fitting of its bony parts as the head of the humerus is very large compared with the smmall, shallow socket formed by the glenoid cavity 2:Ligamentous factors: The capsule and its ligaments are weak and lax 3: Muscular factors: The inferior aspect of the joint is not supported by any muscles. Mention the factors that the stability of the joint depends on It depends on the strength of the muscles around it: - Above: Supraspinatus, long head of biceps & coraco acromial arch. - In front: Subscapularis. - Behind: Infraspinatus & teres minor. Gehad Sayed MSK 1 Below: - The joint is not supported by any muscle below, where the capsule is lax and bulges in the quadrangular space. Explain why Upward dislocation of shoulder joint is rare Due to: 1.The presence of the coraco-acromial arch 2. Support of the rotator cuff muscles. Explain why Most dislocations of the humeral head occur in downward (inferior) direction As The axillary nerve may be injured by direct Compression of the humeral head on the nerve inferiorly as it passes through the quadrangular space. Elbow joint: pulled elbow Explain why: Pulled elbow usually occurs in children under 5 years of age It is commonly caused by a sharp pull of the child's hand, mainly if the child resists. The not yet developed head of the radius descends from the lax annular ligament of the radius. Wrist joint Enumerate Relations to the wrest joint A. Anteriorly: Flexor retinaculum and the structures passing both deep and superficial to it. Gehad Sayed MSK 1 B. Posteriorly: Extensor retinaculum and the structures passing .deep to it C. Laterally: Anatomical snuff-box . Enumerate Structures deep to extensor retinaculum Mention the contents of carpal tunnel a) Tendon of flexor pollicis longus and its synovial sheath (radial bursa) Gehad Sayed MSK 1 (b) Median nerve c) 4 tendons of flexor digitorum profundus d) 4 tendons of flexor digitorum superficialis (8 tendons are surrounded by the common fiexor synovial sheath C. Vessels: Mention the branches of the axillary artery Branches of first part: 1. Superior thoracic artery Branches of 2nd part: 1. Thoracoacromial artery 2. Lateral thoracic artery Branches of 3rd part: 1. Subscapular artery: 2. Anterior circumflex humeral artery 3. Posterior circumflex humeral artery Enumerate Branches of brachial artery 1.Profunda brachi artery 2.Muscular branches: biceps, brachialis and coraco-brachialis . 3.Nutrient artery to the humerus 4. Superior ulnar collateral artery: (posteriorly) . Gehad Sayed MSK 1 It accompanies ulnar nerve and shares in anastomosis around the elbow. 5. Inferior ulnar collateral artery: (anteriorly) It shares in anastomosis around the elbow 6 :Terminal branches . -Radial artery - Ulnar artery Enumerate Branches of radial artery From above downwards: In the Forearm: 1. Radial recurrent artery 2. Muscular branches: In the Wrist: 3. Anterior carpal artery 4. Posterior carpal artery In the palm of the hand: 5. Superficial palmar branch 6. Deep palmar artery In the dorsum of the hand: 7. Dorsal digital branch to the thumb 8. First dorsal metacarpal artery Gehad Sayed MSK 1 9. Princeps pollicis artery 10. Radialis indicis artery Enumerate Branches of ulnar artery From above downwards : In the forearm: 1. Anterior ulnar recurrent artery 2. Posterior ulnar recurrent artery . 3. Muscular branches 4. Common Interosseous artery Anterior and posterior interosseous arteries In the wrist: : 5. Anterior carpal artery . 6. Posterior carpal artery: In the palm of the hand : 7. Deep palmar branch . 8. Superficial palmar arch Enumerate branches of anterior interosseous artery : Branches . 1. Median artery: which accompanies and supplies the median nerve (vasa nervosa) Gehad Sayed MSK 1 2. Muscular branches: to the muscles of the front of the forearm 3. Nutrient arteries: of both radius and ulna 4. Carpal artery: at the upper border of pronator quadratus (before piercing the Interosseous membrane, it gives a descending carpal branch which .Descends deep to pronator quadratus to join the anterior carpal arch. Enumerate branches of posterior interosseous artery : Branches : 1. Posterior interosseous recurrent artery It arises near its origin and ascends to Anastomose with the posterior descending Branch of profunda brachi on the back of .The lateral epicondyle 2. Muscular branches to the muscles of the Back of forearm Mention the effects of Radial nerve injury at the level lower one third of humerus 1- Fingers drop. 2- Wrist drop due to paralysis of all extensors of the wrist. Gehad Sayed MSK 1 Gehad Sayed MSK 1 Mention the branches of brachial plexus Branches: I- From the roots : 1- Nerve to rhomboids (dorsal scapular nerve) (C5). 2- Nerve to serratus anterior (long thoracic nerve of Bell) (C5,6 &7): 3- Branch from C5 to join the phrenic N. (C3, 4, 5). 2- Branches from trunks (upper trunk only) 1- Nerve to subclavius (C5, 6). 2- Suprascapular nerve (C5, 6). Gehad Sayed MSK 1 3- Branches from the cords - Lateral cord: 1- Lateral pectoral nerve (C5, 6, 7). 2- Lateral root of median nerve (C5, 6, 7). 3- Musculocutaneous nerve (C5, 6, 7). The largest branch. - Medial cord: 1- Medial pectoral nerve (C8, T1). 2- Medial root of median nerve (C8, T1) Gehad Sayed