Musculoskeletal attachment site markers and skeletal pathology of the forearm and carpal bones from Tell Abraq, United Arab Emirates, c. 2300 BC
Skeletal morphology and pathology are frequently used to support theories of activity patterns in prehistoric populations. In this study, the adult forearm (n = 307 radii and ulnae) and wrist bones (n = 500 scaphoid and lunate) from the Tell Abraq tomb, United Arab Emirates (ca. 2300 BC), were assessed for morphological variations and pathologies. Specifically, musculoskeletal attachment sites (MAS) were evaluated for indications of stress and articular surfaces were assessed for the presence of osteoarthritis (OA).
OA was prevalent on the distal forearm bones (radius 40% and ulna 35%). Additionally, OA at the proximal ulna (73%) strongly correlated with (MAS) stress marker scores of elbow joint flexion (brachialis: rs = .323, p<.01) and extension (triceps: rs = .473, p<.01; anconeus: rs = .330, p<.01) as well as forearm rotation (supinator: r s = .373, p<.01; pronator teres: rs = 344, p<.01). The medial head of the triceps, anconeus and supinator muscles provide medial stability at the humeroulnar joint.
Musculoskeletal attachment site stress indicators for the thumb were indicative of repeated or strained movements in extension and abduction and correlated strongly with proximal OA at the ulna (extensor pollicis longus: rs = .452, p<.01). Side did not correlate with OA, probable sex or any of the MAS stress markers.
An unusual finding of an elevated transverse ridge was observed at the trochlear notch of the ulna. Presence of the transverse midtrochlear ridge (TTR) (58%) was positively correlated with proximal elbow joint OA (r s = .330, p<.01) and assigned sex (rs = .263, p<.01). Eighty-five percent of assessed radii had a depressed facet for the attachment site of the volar carpal ligament and 34% of the scaphoid bones had an exaggerated dorsal ridge for attachment of the dorsal carpal ligament of the wrist. The high levels of OA at the distal radius and proximal ulna in conjunction with the MAS data lend support to the theory that the individuals from the Tell Abraq tomb were engaged in regular heavy and repetitive bimanual activities with their upper extremities.