Split flexor carpi radialis muscle

A detailed anatomic and intramuscular neural staining study in 22 human and 5 monkey upper limbs revealed that the flexor carpi radialis can be raised on its proximal neurovascular pedicle and that the muscle can be split alo ng its tendon into two independently functioning neuromuscular compartments , each with its own nerve and blood supply. A study of the muscle architect ure in the human specimens found the radial compartment to have significant ly longer fiber length and a larger physiologic cross-sectional area than t he ulnar compartment. Independence of function of each compartment was demo nstrated in electrical stimulation studies in six monkeys (Macaca fascicula ris), but no significant difference was noted in the peak isometric load be tween the two compartments (p = 0.68) in the monkey. The extra functioning muscle units become important in local transfers for restoring function in multiple nerve Daisies as in Hansen's disease, severe traumatic loss of mus cle in crush injuries and compartment syndromes, and after wide resection i n infective and neoplastic conditions in the forearm and hand.