Shoulder girdle and arm Jim Clough 2007 SX102 Anatomy Shoulder girdle and arm Jim Clough 2007

Anatomical reference position and location terminology

Appendicular anatomy This session will detail the structure and function of the upper appendicular anatomy, i.e. the shoulder girdle & arms. Whilst the various muscles or muscle groups will be considered chiefly in isolation, you should be aware that this is not the circumstance in which these structures normally operate. Terms such as synergists and stabilisers are particularly relevant in this context (n.b. rotator cuff below).

Shoulder girdle – skeletal anatomy This comprises an incomplete ring of bony structures and associated musculature. Bony system: scapulae and clavicles clavicles - proximal attachments to the manubrium of the sternum at the sterno-clavicular joints; and distally to the scapulae at the acromio-clavicular joints. scapulae - to the spine from their medial borders by the rhomboids and trapezius.

Bones of the shoulder girdle The shoulder girdle is an incomplete ring comprising the scapulae and clavicles. The scapulae link to the spine via, amongst others, the trapezius and rhomboid muscles. The anterior aspect of the girdle is joined to the torso at the sterno-clavicular joint.

Scapula anterior posterior clavicle Bony detail of the scapula and clavicle.

Broken “collar bone” Clavicular fracture is quite common in sport. Note the swelling circled on left picture and the fracture on the x-ray

Shoulder joint – skeletal anatomy This is formed by the meeting of the head of the humerus and a shallow depression on the lateral aspect of the scapula, the glenoid fossa, the joint is also known as the gleno-humeral joint The glenoid fossa is oriented slightly to the anterior and acts as a surface on which the humeral head pivots, as distinct from the hip, where the femoral head is partially enclosed and held by the acetabulum. This arrangement, in comparison to the hip, allows considerable range of movement, at the expense of some stability.

Shoulder (gleno-humeral) joint Acromio-clavicular joint Note the joint is merely a sliding contact of the humeral head with the glenoid fossa. Shoulder stability is down to ligaments, joint capsule and muscle, with some protection from displacement by the acromion and coracoid processes

Shoulder girdle movement There is limited movement at the acromio-clavicular. Muscles involved in shoulder girdle elevation, e.g. trapezius, levator scapulae, will produce a shrugging action, causing an upward movement of the lateral end of the clavicle, this would be termed sterno-clavicular elevation also. The reverse of this action is depression. Consider what muscles might cause this (as distinct from just allowing the shoulders to drop).

Sterno-clavicular movement The sterno-clavicular can also undergo forward and backward rotation. In this, the distal end of the clavicle is moved forwards or backwards. Forward rotation is demonstrated in the pushing forward of the whole arm from the shoulder, as at the top of a press up. This is also termed protraction in terms of the shoulder girdle as a whole. Backward rotation (or retraction) completes the actions.

Shoulder girdle – muscular anatomy The shoulder girdle acts as a structure encircling the upper torso, giving a base for arm action and enhancing range of movement. Muscular anatomy: the muscles of the shoulder girdle may be defined as being attached from the torso to the girdle (as distinct from torso or girdle to the arm). However, as the shoulder joint works in league with the shoulder girdle, such definitions are not that useful beyond a dry classification system.

Some major shoulder girdle muscles Trapezius – scapular adduction, cervical extension, elevation Rhomboids – scapular adduction and stabilisation Pectoralis minor – scapular stabilisation Levator scapulae – elevation Serratus anterior – scapular abduction/stabilisation

Note the extreme trapezius and deltoid development in these illustrations.

Shoulder girdle movement Note the considerable range of movement possible in sterno-clavicular elevation and depression. Protraction and retraction offer almost as much also.

Muscles of the shoulder joint Associated muscles: Deltoids flexion, extension and abduction Pectoralis maj. horiz. flexion, protraction, depression Latissimus dorsi adduction, extension Biceps (weak flexion) suspraspinatus* Triceps (weak extension) subscapularis* Coracobrachialis infraspinatus* Teres major teres minor* * rotator cuff group, humeral rotation & stabilisation

Deltoid work

Pectoralis major (pecs) work Dips

Elbow joint – skeletal anatomy This is the joint between the humerus and the bones of the forearm, radius and ulna. The gliding joint between the radius and ulna, just distal to the elbow is the radio-ulnar joint. The elbow is capable of flexion and extension, whilst the radio-ulnar joint is involved in pronation and supination.

The arm - with detail of the elbow joint The arm - with detail of the elbow joint. Note the radio-ulnar joint which allows pronation and supination of the hand.

Elbow joint – muscular anatomy Biceps – flexion and supination (n.b. shoulder actions above) Triceps – extension (n.b. …..above) Brachialis – flexion Brachio-radialis – flexion, pronation & supination Further assistance to pronation and supination is given by the supinator, pronator teres and pronator quadratus

Biceps and triceps

Working on the biceps A normal bicep and, what can be done with a bit of hard work ..and, some … vitamins.

Forearm and hand anatomy Things get a bit more complicated here; there are two forearm bones, eight wrist bones, five hand bones and 14 finger and thumb bones (27). A variety of muscles are involved in the complex movements of the hands and fingers, but you will not be expected to learn these at this stage. phalanges

Wrist actions ( all based on the ARP) Adduction or ulnar deviation Abduction or radial deviation Palmar flexion or wrist flexion Dorsi-flexion or wrist extension Pronate - to turn the hand palm down* Supinate – to turn the face up* ( you may use these terms as the muscles acting e.g. wrist supinators, w. flexors etc) *these are really radio-ulnar movements

Training principles - regression To be fair, there’s at least 30 years between these photos.