SHOULDER ANATOMY

Patient Education Page

SHOULDER TOPICS

Impingement Syndrome

Shoulder Instability

Rotator Cuff Tears

*These pages are for informational purposes only and are not intended as medical advice.  Please consult a physician for specific diagnosis and treatment options*

The shoulder is comprised of three bones:  the clavicle (collarbone), the humerus (upper arm bone) and scapula (shoulder blade-not shown in this diagram).  These bones are held in place by muscles and tendons that help to provide stability and strength to the shoulder.  Four of these muscle/tendon groups form the rotator cuff.  Between the rotator cuff and the acromion is a "jelly-like" tissue known as bursa.  The bursa acts as a barrier between the acromion (a bone on the upper edge of the scapula) and the rotator cuff and permits the smooth gliding action when you raise your arm.

There are also two joints within the shoulder.  The acromioclavicular joint (or AC joint) is found between the acromion and the clavicle.  The glenohumeral joint, also known as the shoulder joint, is a ball and socket type joint that allows the great range of motion that the shoulder has.  The ball portion of the joint is the top of the humerus bone.  The socket is a very shallow "plate-like" structure known as the glenoid.  A soft tissue capsule encircles the glenohumeral joint and ligaments also anchor the capsule in place to help provide shoulder stability.