Report of a Transligamentous Ulnar Nerve SensoryBranch

摘要

Background: Several anatomical variations of the median nerverecurrent motor branch have been described. No previous reports have describedthe anatomical variation of the ulnar nerve with respect to transverse carpalligament. In this article, we present a patient with symptomatic compression ofthe ulnar nerve found to occur outside the Guyon canal due to a transligamentouscourse through the distal transverse carpal ligament. Methods: A59-year-old, right-hand-dominant male patient presented with right hand pain,subjective weakness, and numbness in both the ulnar and the median nervedistributions. Electromyography revealed moderate demyelinating sensorimotormedian neuropathy at the wrist and distal ulnar sensory neuropathy. At the timeof planned carpal tunnel and Guyon canal release, a transligamentous ulnar nervesensory common branch to the fourth webspace was encountered and safelyreleased. Results: There were no surgical complications. Thepatient’s symptoms of numbness in the median and ulnar nerve distributionclinically improved at his first postoperative visit. Conclusions:We have identified a case of transligamentous ulnar nerve sensory branchencountered during carpal tunnel release. To our knowledge, this has not beenpreviously reported. While the incidence of this variant is unknown, handsurgeons should be aware of this anatomical variant as its location puts it atrisk of iatrogenic injury during open and endoscopic carpal tunnel release.