Anatomical composition of the anterior shoulder joint capsule. A cadaver study on 12 glenohumeral joints.

Twelve right cadaver shoulder joints were investigated after alcohol-formalin-glycerol fixation. The tendons of the "rotator cuff" were separated from the joint capsule. The capsulo-ligamentous structures: Lig. coracohumerale, Lig. coracoglenoidale and Ligg. glenohumeralia were dissected. In addition to the Ligg. glenohumerale superius, medium et inferius, an "unknown glenohumeral ligament" coursed in the midline of the superficial layer of the anterior shoulder joint capsule. It arose from the axillary part of the Lig. glenohumerale inferius and the insertion tendon of the Caput longum m. tricipitis brachii, coursed upwards laterally and fused with the Lig. glenohumerale medium. Between the Ligg. glenohumerale medium et inferius it was connected with the shoulder joint capsule by loose connective tissue. Craniolaterally it melted into the superior portion of the M. subscapularis and inserted together with its tendon to the Tuberculum minus of the Humerus. The ascending fibres of the "unknown glenohumeral ligament" and the oblique, descending fibres of the Ligg. glenohumeralia medium et inferius crossed twice and formed X-shape connections between the ligaments. In external rotation and abduction or anteversion the course of fibres of the "unknown glenohumeral ligament" was spiral. According to the shape and anatomical position of the "unknown glenohumeral ligament" we propose to name it "Lig. glenohumerale spirale".