Anomalous composition of musculature of the first dorsal fibro-osseous compartment of the wrist.

The anomalous orientation of musculature of the first dorsal fibro-osseous compartment of the wrist is clinically relevant to De Quervian's stenosing tenosynovitis and reconstructive surgeries. Split insertion of the abductor pollicis longus (APL) is commonly found in chimpanzees, gorillas and gibbons. A comparable identical pattern of anomalous slips in humans is of anthropological and phylogenetic importance and could be a result of atavism.