A rare cause of carpal tunnel syndrome: Ultrasonographic findings of bifid median nerve

Abstract

Carpal tunnel syndrome (CTS) is an entrapment neuropathy of median nerve because of many pathological reasons at the wrist. Several diseases are responsible in the etiopathogenesis of CTS and anatomical variation of the median nerve is one of these reasons. A woman aged 39 years old who had pain and numbness in her first three fingers applied electrophysiology unit. Electrophysiological studies showed grade 5 CTS on the right hand and grade 4 on the left. Ultrasonographic studies showed bilateral high cross sectional area of the median nerve at the levels of radioulnar joint, psiform and hamate and median nerves echo were low bilaterally. Median nerve cross sectional area was 18.8 mm2 on the left wrist at the psiform level. But median nerve has two branches with area of 21.2 mm2 and 14.3 mm2 at the right wrist. The ultrasonographic findings of bifid median nerve, a rare anatomical variation, were discussed along with the review of the literature.