The transverse midtrochlear ridge: Morphological adaptation or pathological response at the humeroulnar joint?

Abstract

An unusual transverse ridge was documented at the trochlear notch of the ulna in an adult sample from the Bronze Age tomb at Tell Abraq, United Arab Emirates (2200 BC), located on the Arabian gulf. The tomb housed over 300 individuals that were disarticulated and commingled.The ulna (n = 166), radius (n = 201) and scaphoid (n = 274) bones were assessed for morphological variations and pathology. Eighty‐five percent of assessed radii had a depressed facet for attachment of the volar carpal ligament and 34% of the scaphoid bones had an exaggerated dorsal ridge for attachment of the dorsal carpal ligament. While assessing the ulnae an elevation at the transverse midtrochlear region was identified on 58% of the sample. This ridge appears to be a newly documented anatomical phenomenon. There was a strong positive correlation between the presence of this transverse midtrochlear ridge (TTR), proximal elbow joint OA (rs = .330, p<.01) and assigned sex (rs = .263, p<.01) showing a strong correlation in males. We hypothesize that this transverse elevation at the trochlear notch increased stability at the medial elbow joint in this population. The presence of the TTR in conjunction with the findings on the radii and scaphoid bones suggest that the inhabitants of Tell Abraq lived physically arduous lives.