[The course of the median nerve in the carpal canal].

In 111 adults, 3 children and 12 infants the position of the N. medianus and its course through the forearm and the carpal tunnel are examined. In 10% of the adults, deviations from the normal position occur. In 5% of the cases, the nerve does not run radially, but between the tendons for the third and fourth fingers of the M. flexor digitorum superficialis through the carpal tunnel. In another 5% of the cases, the median nerve does not pass superficially but deep beneath the flexor tendons of the fingers, either radially or in the middle of the carpal tunnel, so that he cannot be seen after cutting the transverse ligament (flexor retinaculum). Before disappearing deep between the tendons, the nerve crosses over them. The same observations can be made in infants. The significance of the medial and deep position of the nerve within the carpal tunnel as well as its crossing over the tendons in its course through the forearm is discussed with respect to surgical procedures for opening the carpal tunnel.