Anomalous Innervation of the Intrinsic Hand Muscles in a Patient with Carpal Tunnel Syndrome

ABSTRACT

Background: Communications between the median and ulnar nerves in the hand provide for variations in the motor innervation of the intrinsic hand muscles. The presence of an anomalous communication may complicate the interpretation of electrodiagnostic findings.

Findings: We reported here a 56-year-old woman; her thenar muscles had been spared by ulnar-to-median anastomosis despite severe carpal tunnel syndrome.

Conclusions: The presence of the ulnar-to-median anastomosis may complicate the interpretation of electrodiagnostic findings. Clinicians should be aware of this possibility, especially in the presence of paradoxical clinical and electrodiagnostic findings.

KEYWORDS. :

• Carpal tunnel syndrome
• electrodiagnosis
• ulnar-to-median anastomosis
• thenar eminence