The three main bones of the shoulder are the humerus (upper arm), the clavicle (collar bone) and the scapula (shoulder blade).
The joint cavity is made up of the head of the humerus and face of the glenoid (part of the scapula). The scapula extends up and around the shoulder joint at the rear to form a roof called the acromion, and around the shoulder joint at the front to form the coracoid process.
The end of the scapula, called the glenoid, meets the head of the humerus to form a glenohumeral cavity that acts as a flexible ball-and-socket joint. The joint is stabilised by ligaments and a ring of fibrous cartilage surrounding the glenoid called the glenoid labrum.
Ligaments connect the bones of the shoulder, and tendons join the bones to surrounding muscles. The biceps tendon attaches the biceps muscle to the shoulder and helps to stabilise the joint while it is moving.
Four short muscles originate on the scapula and pass around the front and back of the shoulder joint. these muscles together form the rotator cuff and provide further dynamic stability to the shoulder joint.
All of these components of your shoulder, along with the muscles of your upper body, work together to manage the stress your shoulder receives as you extend, flex, rotate, lift and throw.
Shoulder injuries often occur when you have fallen directly on the shoulder, an outstretched arm or just from overuse. Sprains of ligaments that hold the bones together, tendon inflammation or muscle strains are the most common of shoulder injuries. A good stretching and strengthening program often reduces the chances of acquiring a shoulder injury. Consult your local physiotherapist for shoulder stretching programs.
Symptoms in the shoulder may include pain, swelling, loss of normal shoulder movement, deformity, or burning/numbness down the arm and hand. If you have burning, numbness or deformity for any reason, seek medical assistance immediately.
Find More Information
Bone and Shoulder Joint Related Conditions
Other Soft Tissue Conditions
Nerve Related Conditions