The anatomy of the superior labrum and biceps origin in the fetal shoulder

Abstract

The presence of a sublabral recess has been observed in adult shoulders. It is unclear whether this occurrence is a developmental variation or is acquired. The primary objective of the study was to determine if a cleft exists between the superior labrum and the superior cartilaginous glenoid anlage during the second trimester. The secondary objective was to define the origin of the long head of the biceps in the human fetus in the second trimester. Shoulders of 11 fetuses, 11-20 weeks old, were sectioned in the coronal plane. The superior labrum was observed to be continuous with the superior glenoid anlage, and a cleft was not observed at any stage of development. The biceps tendon originated from the superior labrum and the superior glenoid tubercle anlage in all specimens. Fibers extending in the direction of superior glenoid tubercle anlage were always very prominent.

Histology, vascularity and innervation of the glenoid labrum

“…The glenoid labrum was sparsely vascularized without any configurative pattern of distribution and the vascularity was observed to decrease with age. 24 In contrast, one study 25 reported that the vascular channels proliferating inside the glenoid labrum and glenoid bone increased with gestational age. The current study observed that the consistency of the superior half of the glenoid labrum was rubbery in 97.86% ( n = 137) and firm in 2.14% ( n = 3) of specimens, whereas the entire inferior half was firm.…”

“…The glenoid labrum was sparsely vascularized without any configurative pattern of distribution and the vascularity was observed to decrease with age. 24 In contrast, one study 25 reported that the vascular channels Alashkham et al…”

Development of the Human Biceps Brachii Tendon and Coracoglenoid Ligament (7th-12th Week of Development)

“…Some authors have shown in adults [Standring, 2008] and in fetuses [Aboul-Mahasen and Sadek, 2002;Lapner et al, 2010] that the LHBT originates from the glenoid labrum and the supraglenoid tubercle. Several authors found the main origin of the LHBT in the supraglenoid tubercle (25% of cases [Pal et al, 1991] and 40-60% of cases [Vangsness et al, 1994]), and there are studies that report that in 6.4% of cases the LHBT originates only from the supraglenoid tubercle [Demondion et al, 2001].…”

“…However, developmental studies on the origin of the LHBT from the glenoid labrum and the scapula are scarce. Some studies describe the LHBT as originating from the glenoid labrum and the supraglenoid tubercle in all specimens, both in fetuses [Aboul-Mahasen and Sadek, 2002;Lapner et al, 2010] and in adults [Pal et al, 1991;Tuoheti et al, 2005]. Other authors have stated that the LHBT is not attached to the supraglenoid tubercle [Gigis et al, 1995] and even have described it as originating only from the supraglenoid tubercle in 6.4% of the cases [Demondion et al, 2001].…”