Shoulder

Shoulder

The shoulder is one of the largest and most complex joints in the body. It has the greatest range of motion, which makes it highly susceptible to injury. The shoulder joint is comprised of the humerus (upper arm bone) that fits into glenoid of the scapula (shoulder blade), like a ball and socket. Other important bones in the shoulder include:

• The acromion is a bony projection off the scapula.
• The clavicle (collarbone) meets the acromion in the acromioclavicular (AC) joint.
• The coracoid process is a hook-like bony projection from the scapula.

The shoulder has several other important structures:

• The rotator cuff is a collection of muscles and tendons that surround the shoulder, giving it support and allowing a wide range of motion. The muscles that comprise the rotator cuff are: Supraspinatus, Inraspinatus, Teres Minor and Subscapularis (SITS)
• The capsule, which completely encircles the joint, separates the joint from the rest of the body, and contains the joint fluid.
• The bursa is a small sac of fluid that cushions and protects the tendons of the rotator cuff.
• A cuff of cartilage called the labrum forms a cup for the ball-like head of the humerus to fit into.