Carpal Tunnel Syndrome Caused by Bifid Median Nerve in Association with Anomalous Course of the Flexor Digitorum Superficialis Muscle at the Wrist

Abstract

Although lipomas are benign fatty tumors that are common in humans, lipomas causing compressive neuropathy are rare. Furthermore, compressive neuropathy of the median nerve in the distal forearm just proximal to the carpal tunnel has never been reported. We report a very rare case of symptomatic lipoma causing median neuropathy in the distal forearm, associated with bilateral carpal tunnel syndromes.

Anatomical Variations of the Lumbrical Muscles Causing Carpal Tunnel Syndrome

“…In a bifid median nerve, an accessory muscle or a median artery may run in-between the division. The accessory muscles reported include the first lumbrical, palmaris longus, FDS muscle (Park et al 2017;Atoni et al 2017) and palmaris profundus. Presence of these anatomical variations are frequently associated with median nerve compression (Al-Qattan et al 2009).…”

Edge-Morphology Detection Approach for Median Nerve Segmentation on Ultrasound Images

“…Suppose an input image g(x, y) is composed of discrete gray levels in the dynamic range of [0, L-1]. The transformation mapping C (rk) of HE is given by (3).…”

“…The input image ROI is then selected. The image contrast is modified using CLAHE by (3). At the end of this satge, the image is changed from a gray-scale image to a binary image using Otsu.…”

“…The most important local symptoms CTS are that it increases the stiness of the exor retinaculum, causes inammation of the exor tendon sheath and anatomical variants of the nerve, especially with concomitant additional arteries and in the presence of anomalous muscles. Furthermore, systemic morbidities including obesity, diabetes, hypothyroidism, arthritis, or even physiological circumstances like menopause or pregnancy are established risk factors for CTS [3,4].…”

Carpal Tunnel Syndrome Caused by High Division of the Median Nerve Proximal to the Carpal Tunnel: A Case Report

“…Carpal tunnel syndrome (CTS) is a common neuropathy caused by entrapment of the median nerve by a thickened flexor retinaculum in the wrist 4,9,14) . However, various causes of secondary CTS have been reported, including vascular anomalies involving persistent median artery, variations of the median nerve, and space-occupying lesions in the wrist and palm [1][2][3][4][7][8][9]13) . High division of the median nerve proximal to the carpal tunnel (known as a bifid median nerve) is a median nerve anomaly with incidence rate of 2.8% 7,9) .…”