Shoulder Bursitis Anatomy
To better understand shoulder bursitis, it helps to understand the anatomy of the shoulder joint.
A bursa is a small sac that is filled with very slippery fluid. The bursa acts as a lubricating pad between a tendon and bone. This prevents destruction of the tendon as it moves over a bone.
The shoulder joint allows motion between two major bones: the humerus (arm bone) and the scapula (shoulder blade). The shoulder joint is a ball and socket joint. A depression in the scapula, known as the glenoid, provides the socket for the head of the humerus. Ligaments and muscles hold the joint together as the bones move.
The clavicle, or collar bone, connects to the scapula at the acromion, which is a bony projection off the scapula. The acromioclavicular ligaments normally surround and secure this joint.
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