Kaplan anastomosis of the ulnar nerve: a case report

INTRODUCTION: The sensory innervation of the hand is usually unvarying and anomalies in this area are uncommon. CASE PRESENTATION: We report the case of a rare ulnar nerve branch called a Kaplan anastomosis, which anastomosed the dorsal cutaneous branch with the ulnar nerve prior to its bifurcation into the superficial and deep ramus. CONCLUSION: Many authors have reported unusual ulnar nerve branches and knowledge of these anatomical variations is important for the interpretation of pain and sensory loss in the area sustained during injuries or surgical procedures. Our finding is the fourth case of a Kaplan anastomosis to be described in the literature.