Bifid Median Nerve Compression due to a Musculotendinous Anomaly of FDS to the Middle Finger

Abstract

A case is presented of a bifid median nerve whose longest portion had a normal course while the other portion passed through a hole in the FDS tendon of the middle finger, at its musculotendinous junction. This caused nerve compression during muscle contraction, producing pain and dysaesthesia in the middle finger suggesting carpal tunnel syndrome.

Anatomical variations of the carpal tunnel structures

“…Bifurcation of the median nerve proximal to the transverse carpal ligament is a relatively common anatomical variation present in 1% to 3.3% of individuals undergoing carpal tunnel release surgery ( Figure 1) (1)(2)(3). High bifurcation of the median nerve can be an isolated finding (7) or it can be associated with a persistent median artery (4) or an accessory muscle belly of the long finger flexor superficialis (1,5,6). A case of a bifid median nerve wherein the radial-sided branch was located in its own compartment within the carpal tunnel has been identified by the senior author (AT) (Figure 2).…”

Bilateral Palmaris Profundus in Association With Bifid Median Nerve as a Cause of Failed Carpal Tunnel Release

“…These are most frequently associated with a median artery, 1,2 although they may occur with no associated structures. 18 -20 An accessory first lumbrical, 21 an arteriovenous malformation, 22 and a flexor digitorum superficialis muscle to the middle finger (proximally) 23 also have been reported in association with a bifid nerve. Separate compartments at the carpal tunnel have been described by Amadio 24 and Szabo and Pettey 25 with compression potentially occurring for each branch.…”

Bifid Median Nerve in Trauma Patients: How Rare Is it?

“…Similarly, Fernandez-Garcia et al [8] presented a case of bifid median nerve where one branch had a normal distribution while the other one had an anomalous course through the FDS (flexor digitorum superficialis) tendon of the middle finger at the level of the musculotendinous junction, and this anomalous route of the branch caused nerve compression with the middle finger only symptomatically involved. In 1983, Kornberg et al [9] described a bifid median nerve with three thenar muscles.…”