Coracoacromial ligament

Structure

The coracoacromial ligament originates from the summit of the acromion of the scapula, just in front of the articular surface for the clavicle. It inserts by its broad base along the whole length of the lateral border of the coracoid process of the scapula.

The clavicle and under surface of the deltoid muscle are above it. The tendon of the supraspinatus muscle (and its bursa) are below it.

Its lateral border is continuous with a dense lamina that passes beneath the deltoid muscle upon the tendons of the supraspinatus and infraspinatus muscle.

The ligament is sometimes described as consisting of two marginal bands and a thinner intervening portion, the two bands being attached respectively to the apex and the base of the coracoid process, and joining at the acromion.

When the pectoralis minor is inserted, as occasionally is the case, into the capsule of the shoulder-joint instead of into the coracoid process, it passes between these two bands, and the intervening portion of the ligament is then deficient.