Anatomy of the superior labrum complex of the shoulder

Abstract

The outstanding progress achieved in MRI and arthroscopic techniques has forced orthopedic surgeons to consider the anatomy of the shoulder joint in detail. The superior labrum complex shows a broad range of variations, which is the reason for some difficulties regarding diagnostic conclusions as well as therapeutic considerations. In particular, the differentiation between the normal and pathological adherence of the labrum is a serious clinical problem. The glenoid labrum consists of circularly arranged collagenous fibers attached to the osseous margin of the glenoid by a fibrocartilaginous transitional zone. The cranial part of the labrum is more compact than the caudal one. It is also connected to the joint capsule and the integrated ligaments. Most of the fibers of the long head of the biceps tendon insert at the supraglenoid tubercle, only some of them continue in the fibrous ring. So-called SLAP lesions have to be differentiated from variations. In up to 18% of the patients normal clefts can be seen, e. g., sublabral holes, and in less than 6% other rare variations, e. g., the so-called Buford complex.