Lumbrical muscle with an additional origin in the forearm

Background: Although variations in the attachments of the lumbrical muscles have been commonly reported, these have been seen mainly in the Caucasian population. The present study is the first reported case of such an anomaly in a Chinese cadaver in the literature. Methods: The upper extremities of 26 Chinese (23 male and three female) cadavers were examined. Results: Dissection of a male 66-year-old Chinese cadaver has revealed the rare case of a bipennate first lumbrical muscle with an additional origin extending from the distal part of the forearm. Its first origin arose from the flexor digitorum profundus in the hand distal to the flexor retinaculum. The intrinsic muscles in the hands of all the other cadavers were normal. Conclusions: An anomalous origin of the lumbrical from muscles in the forearm has the potential to cause compression of the median nerve in the carpal tunnel.