MUSCULUS-COMITANS-NERVI-MEDIANI (M-PALMARIS-PROFUNDUS)

Palmaris profundus muscles were found in two cadavers during routine d issection of the upper limb. This rare muscle was found in two forms. In the first case, the muscle resembled a diminutive palmaris longus w ith the belly arising from the common flexor tendon. In the second cas e however, a reversed muscle with the belly emerging from beneath the transverse carpal ligament and its long thin tendon extended to and in serted in the common flexor tendon. The similarity therefore of these muscles to variable forms of palmaris longus is remarkable but they di ffered in one very important aspect from palmaris longus. The muscles are of special interest because, in both cases, the muscles were found enclosed in a common fascial sheath with the median nerve. These unus ual muscles, in spite of mimicking palmaris longus, may perhaps, be be tter named ''musculus comitans nervi mediani'' to denote their very im portant relationship to the median nerve, that of being the intimate t raveling companion of the median nerve through the forearm and into th e hand by way of the carpal canal beneath the transverse carpal Ligame nt. In one case, a well developed median artery was also found which a lso entered the carpal canal along with the median nerve and its muscu lar companion.