Shoulder and Elbow Anatomy Sarah Rayner Extended Scope Practitioner Physiotherapist Dr Tim Hughes GPSI MSK Orthopaedic Services

Surface Anatomy Shoulder – Acromion (lateral border, post angle, ant edge) – AC joint line – Coracoid – Greater and lesser tuberosities – Insertions of supraspinatus, infraspinatus and suscapularis – Identify muscle bellies of supraspinatus, infraspinatus and teres minor – Outline of the scapula – C4 and C5 dermatomes Elbow – Head of the radius – Radio-humeral joint line – Ulner, median and radial nerve innervation of the skin – Lateral and medial epicondyles and common flexor and extensor origins – Insertion of biceps – C5/6 and 7 dermatomes

Shoulder Anatomy With its 5 joints, 8 ligaments and 30 muscles, the shoulder complex presents a compromise between stability and mobility, and the result is that it is inherently unstable.

Biomechanics of shoulder elevation Humerus rotates about the scapula at the GH joint, the scapula rotates about the clavicle at the AC joint and the clavicle rotates about the sternum at the SC joint. Normal movement required at all joints for full elevation to occur – efficient scapulo-humeral rhythm (Codman 1934). Ratio GH to scapula movement 2:1

Shoulder Muscles Scapula Pivoters – (Trapezius, Serratus ant, Rhomboids, lev scap) Glenohumeral protectors – (RC & LHB) Humeral positioners – (deltoid) Power Drivers (Teres major, pec major and lat dorsi)

Rotator Cuff

Shoulder Summary Shoulder complex movement occurs through the GHJ, ACJ, SCJ and scapula-thoracic gliding mechanism. Anatomical structures and neural mechanisms control the Shoulder complex allowing smooth synchronised pain free movement. Shoulder function is significantly dependent on normal biomechanics. Failure of any component may lead to abnormal function of the shoulder complex. Understanding biomechanics – successful assessment and treatment planning.

Elbow Anatomy