Macro/micro observational studies of fibres maintaining the biceps brachii tendon in the bicipital groove: application to surgery, pathology and kinesiology

Background: There is controversy over the nature of tissues covering the bicipital groove protecting the biceps brachii tendon from dislocation/subluxation causing shoulder pain. Recent researches on cadaveric dissection and histological studies have changed the old concept of the transverse humeral ligament covering the bicipital groove to tendinous fibres of the subscapularis or interdigitating fibres of the subscapularis and supraspinatus. The change has not been incorporated into standard text books of anatomy. Therefore, the aim of the study is to support the new or old concept. Materials and methods: Eighteen embalmed shoulders were dissected to determine the nature of the tissues over the bicipital groove. Tissues from 4 shoulders were processed and 16 histological slides were examined for fibre types. Theoretical analysis of ligament and tendon has also been carried out. Results: The dissection study revealed that the tissues over the bicipital groove were tendinous fibres of subscapularis/interdigitating fibres of the subscapularis and supraspinatus and fibrous expansions from the posterior lamina of the pectoralis major. This was supported by the histological slides which showed the signatures of collagen fibres with the characteristics of tendinous fibres. Conclusions: No separate anatomical entity such as the transverse humeral ligament was detected in this study. Thus present study supports the view that the tissues covering the bicipital groove were formed by tendinous rather than ligamentous fibres