The structure and function of the coracohumeral ligament: An anatomic and microscopic study.

Twelve fresh-frozen cadaver shoulders were dissected to study the anatomy and histology of the coracohumeral ligament. Based on the gross and microscopic anatomy, the ligament was found in three variations. In the most common pattern (nine of 12 specimens), the coracohumeral ligament represented a folded portion of glenohumeral joint capsule in the rotator interval between subscapularis and supraspinatus. Because of its inverted "v"-shaped origin from the coracoid base, tension on this structure creates the appearance of a prominent ligamentous structure. However, histologic cross-sections of this pattern of coracohumeral ligament reveal that it is lined by synovium on its undersurface and contains no discretely organized collagen bundles representative of a ligament. The second pattern (two of 12 specimens) was similar, except that the capsular reflection representing the ligament was fused together, giving the structure a more clearly definable anterior edge. In only one specimen was the ligament a truly ligamentous structure. In its normal state the coracohumeral ligament usually appears as a capsular reflection on the coracoid base, and though it courses toward the superior aspect of the intertubercular groove, it is not a true ligamentous structure. These findings support the position of those authors who state that the coracohumeral ligament is unlikely to play a significant role as a suspensory structure in its physiologic state.