Superficial Branch of the Ulnar Nerve

Description

Arising from the ulnar nerve as it enters the hand superficial to the flexor retinaculum, the superficial branch (ramus superficialis nervi ulnaris) courses anteriorly in the hypothenar region, lying palmar to the carpal bones and medial to the thenar eminence. Distally it divides into a proper palmar digital nerve to the ulnar side of the little finger and a common palmar digital nerve that bifurcates for the adjacent sides of the little and ring fingers, tracking along the metacarpals toward the proximal phalanges. Surrounding bony landmarks include the distal ulna and radius at the wrist, the metacarpals, and the phalanges, with articular cartilage indicated at the metacarpophalangeal and interphalangeal joints. An anterior perspective keeps the palmar course and digital distribution clear. Short and direct. Palmar sensory mapping is where this branch matters clinically. Lacerations along the hypothenar eminence or the ulnar border of the palm commonly injure the superficial branch and its palmar digital nerves, producing numbness and dysesthesia in the ulnar one and a half digits while sparing most dorsal ulnar sensation carried by the dorsal cutaneous branch. The relationship to the hook of hamate and adjacent soft tissues also makes it relevant in Guyon canal pathology and in surgical exposure for hypothenar masses, including a palmar ganglion that can displace or compress the nerve. Use this artwork for teaching cutaneous innervation in gross anatomy and hand surgery modules, for figure panels in texts on peripheral nerve injury, and for patient education sheets explaining ulnar-sided palmar numbness after trauma or decompression at the wrist. Anatomical accuracy verified by SciePro's Medical Advisory Board.