Histologic examination of the shoulder capsule shows new layer of elastic fibres between synovial and fibrous membrane.

PURPOSE: In the present study, a systematic histological analysis of the glenohumeral joint capsule was conducted. MATERIALS AND METHODS: 12 cadaveric shoulders were examined. Inclusion criteria were: 1) intact joint capsule and 2) fixation in neutral position. The tissue samples were Elastica Hematoxylin-van-Gieson-(ElHvG) stained and diameter, quantity, and distribution patterns were analyzed. RESULTS: We detected a new layer (elastic boundary layer, EBL) between the synovial and fibrous membrane. The elastic fibres of the EBL differ considerably in diameter, quantity, and distribution pattern. CONCLUSIONS: A previously undescribed layer was noticed, which we named elastic boundary layer for now.