The shoulder is the most flexible joint in the body making it the most susceptible to instability and injury. It is a ‘ball-and-socket’ joint. A ‘ball’ at the top of the upper arm bone, humerus, fits neatly into a ‘socket’, called the glenoid, which is part of the shoulder blade, scapula.
The shoulder joint is made up several bones and soft tissues. It has three bones, the collarbone (clavicle), scapula, and humerus.
Humerus provides attachment to muscles of the upper arm. Scapula is the bone that connects the upper arm bone with the collarbone. It is a flat bone and roughly triangular in shape and provides attachment to the muscles of back and neck.
The clavicle is an S-shaped short bone that connects the shoulder girdle to the body (trunk). It supports the shoulder in a functional position with the axial skeleton so that the arm has maximum range of movement. It also protects major underlying nerves and blood vessels as they pass from the neck to the axilla.
The coracoid process is the extension of the scapula around the shoulder joint at the front portion of the scapula. The acromial process is the extension of scapula around the shoulder joint at the back that forms a roof, acromion.
Glenoid is the smooth shallow depression at the end of scapula that forms the socket of shoulder joint.
The soft tissues of shoulder joint include: