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".

Anatomy of the coracohumeral and coracoglenoidal ligaments.

The Ligg. coracohumerale and coracoglenoidale are constant anatomical structures, represented in all the 34preparations investigated. The Lig. coracoglenoidale is a strong band of dense connective tissue, running from the Processus coracoideus to the Tuberculum supraglenoidale. In 27 specimens out of 34 it was the continuation of the M. pectoralis minor tendon. The Lig. coracohumerale consists of two separate parts. The "inferior part" originates from the Processus coracoideus and the Lig. coracoglenoidale, which separates it from the base of the coracoid process. It is composed of the joint capsule anteriorly and a remnant of the M. pectoralis minor tendon posteriorly. The "superior part" arises from the medio-posterior surface of the Processus coracoideus, just below the Lig. coracoacromiale. Both parts of the Lig. coracohumerale run into the shoulder joint capsule under the M. supraspinatus tendon and insert into a capsular semicircular band. According to the shape and course of fibres between the greater and lesser tubercles of the Humerus, we propose to name it the "Lig. semicirculare humeri". None of the two parts of the Lig. coracohumerale begins from the base of the Processus coracoideus, and fibres of the Lig. coracohumerale do not reach the Tuberculum majus et minus directly.