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

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.