Upper Limb Shoulder & Axilla

Notes

# Anatomy - Upper Limb Sept 18, 2024 ## Shoulder region ### Bones: - Clavicle → connects sternum to scapula (only bony link), superficial, easy to palpate - Scapula → flat, triangular bone (posterior) → spine, acromion, coracoid process - Humerus → proximal end = head (articulates w/ glenoid fossa) ### Joints: - Glenohumeral → synovial, ball-and-socket (↑ range of motion, ↓ stability) - Acromioclavicular → plane synovial - Sternoclavicular → saddle synovial ## Muscles (rotator cuff): - Supraspinatus → initiation of abduction (0-15°) - Infraspinatus → external rotation - Teres minor → external rotation - Subscapularis → internal rotation ## Other muscles: - Deltoid → main abductor (15-90°) - Pectoralis major → adduction, internal rotation - Latissimus dorsi → adduction, internal rotation - Teres major → adduction, internal rotation ## Neurovascular structures: - Axillary nerve → deltoid + teres minor (sensory: lateral shoulder) - Axillary artery → around surgical neck of humerus - Brachial plexus → C5-T1 (roots → trunks → divisions → cords → branches) ## Clinical: - Most common dislocation = anterior (arm in abduction + external rotation) - Risk of axillary nerve injury - Rotator cu...