Capsulitis of the Shoulder Anatomy
To better understand adhesive capsulitis, it helps to understand the anatomy of the shoulder joint.
The shoulder joint allows motion between two major bones: the humerus and the scapula. The shoulder joint is a ball and socket joint. A depression of the scapula, known as the glenoid, provides the socket for the head of the humerus. Ligaments and muscles act to stabilize the scapular-humeral joint during range of motion and weight bearing.
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.
There are four main ligaments supporting the A-C joint. One or more can be sprained (torn) during this injury. The ligaments include:
- Acromioclavicular ligament
- Coracoclavicular ligament
- Deltoid ligament
- Trapezius ligament
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