Thumb Ulnar Digital Nerve Anatomy

  • The ulnar digital nerve supplies sensation to the palmar radial aspect of the thumb and to dorsal skin at the base of the nail.
  • The digital nerves are superficial to the digital arteries in the thumb and fingers.
  • The digital nerves are held in place by the Grayson’s and Cleland’s retention ligaments.
  • The digital nerves supply sensation to the skin, its specialized nerve endings like the Pacinian corpuscles, tendons, and joints.
  • The radial (lateral) common digital nerve branch of the median nerve branches into the radial and ulnar digital nerves of the thumb and the radial digital nerve of the index finger.
Diagrams & Photos
  • Anatomy of the ulnar digital nerve of the thumb.
    Anatomy of the ulnar digital nerve of the thumb.
  • Nerves of the thumb. Note the ulnar digital nerve (UDN), radial digital nerve (RDN), dorsal radial sensory nerve, motor branch of median nerve , palmar cutaneous branch of median Nerve, median nerve (MN), and transverse carpal ligament.
    Nerves of the thumb. Note the ulnar digital nerve (UDN), radial digital nerve (RDN), dorsal radial sensory nerve, motor branch of median nerve , palmar cutaneous branch of median Nerve, median nerve (MN), and transverse carpal ligament.
  • Note Cleland's ligaments dorsal to the neurovascular bundle and Grayson's ligaments volar to the bundle.
    Note Cleland's ligaments dorsal to the neurovascular bundle and Grayson's ligaments volar to the bundle.
  • Nerve with axons enclosed in endoneurium (1); Fascicle enclosed in perineurium (2); Fascicular groups enclosed in connective tissue called internal epineurium (3); Internal epineurium (4); External epineurium (5); Epineural blood vessels (6).
    Nerve with axons enclosed in endoneurium (1); Fascicle enclosed in perineurium (2); Fascicular groups enclosed in connective tissue called internal epineurium (3); Internal epineurium (4); External epineurium (5); Epineural blood vessels (6).
Key Points
  • Sensory nerve patterns vary.  As a result there is a incomplete agreement regarding the amount of dorsal thumb skin innervated by branches of the digital nerve's dorsal branches.
  • The terminal branches of the dorsal radial sensory nerve can provide some sensation to the thumb pulp.
  • The number of nerve fascicles in the digital nerves is variable.
Anatomy References
Anatomic Abbreviations
Hand Surgery Resource Anatomy Diagnostic Guide (Chapter)