Ulnar Nerve

Authors
Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Transverse section of distal forearm1

Transverse section of distal forearm

Transverse cut of the Hand1

Transverse cut of the Hand

Palmar aponeurosis1

Palmar aponeurosis

Motor Innervation

Table 1: Ulnar Nerve Muscle Innervations
Muscle Origin Insertion Innervation Action
1st Dorsal interossei (hand) 1-2nd MCP adjacent sides 2nd dorsal digital expansion
2nd Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 2nd digit: MCP Flexion, PIP & DIP Extension & Abduction
1st Palmar interossei (hand) 2nd MCP (ulnar side) 2nd dorsal digital expansion
2nd Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 2nd digit: MCP Flexion, PIP & DIP Extension & Adduction
2nd Dorsal interossei (hand) 2-3rd MCP adjacent sides 3rd dorsal digital expansion
3rd Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 3rd digit: MCP Flexion, PIP & DIP Extension & Abduction
2nd Palmar interossei (hand) 4th MCP (radial side) 4th dorsal digital expansion
4th Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 4th digit: MCP Flexion, PIP & DIP Extension & Adduction
3rd Dorsal interossei (hand) 3-4th MCP adjacent sides 4th dorsal digital expansion
4th Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 4th digit: MCP Flexion, PIP & DIP Extension & Abduction
3rd Palmar interossei (hand) 5th MCP (radial side) 5th dorsal digital expansion
5th Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 5th digit: MCP Flexion, PIP & DIP Extension & Adduction
4th Dorsal interossei (hand) 4-5th MCP adjacent sides 5th dorsal digital expansion
5th Proximal Phalanx (radial border)		 Ulnar n.
C8 - T1		 5th digit: MCP Flexion, PIP & DIP Extension & Abduction
Adductor pollicis 3rd MCP (plantar surface)
Capitate
2-3rd metacarpal base		 Base of 1st proximal phalanx (ulnar sesamoid) Ulnar n.
C8 - T1		 CMC: Adduction
1st MCP: Flexion
Flexor carpi ulnaris Medial epicondyle
Olecranon		 Hook of Hamate
Base of 5th metacarpal		 Ulnar n.
C7 - T1		 Wrist: Flexion, Ulnar deviation
Flexor digiti minimi brevis (hand) Hook of Hamate
hand_flexor_retinaculum		 Base of 5th Proximal Phalanx Ulnar n.
C8 - T1		 5th MCP: Flexion
Flexor digitorum profundus Proximal 2/3 of Ulna
Interosseous_membrane		 Palmar surface of Distal phalanges 2-5 Median n. (digits 2-3)
Ulnar n. (digits 4-5)
C8 - T1		 Wrist: Flexion
MCP, PIP, & DIP 2-5: Flexion
Flexor pollicis brevis Flexor retinaculum
Capitate
Trapezium		 1st proximal phalanx via radial sesamoid Median n.
Ulnar n.
C8 - T1		 CMC: Flexion
Opponens digiti minimi (hand) Hook of Hamate
hand_flexor_retinaculum		 5th Proximal Phalanx (ulnar border) Ulnar n.
C8 - T1		 5th MCP: Opposition

Entrapment

Note
  • Nyman E, Dahlin LB. The Unpredictable Ulnar Nerve-Ulnar Nerve Entrapment from Anatomical, Pathophysiological, and Biopsychosocial Aspects. Diagnostics (Basel). 2024;14(5):489. Published 2024 Feb 24. doi:10.3390/diagnostics14050489

Examination

  • ULTT3
  • Froment’s Sign
  • Ulnar Claw hand

Ulnar paradox sign

Ulnar Claw hand

Claw hand refers to a passive hand position that is commmonly observed following an ulnar nerve lesion.

Entrapment

Reading list
  • Ulnar nerve p373

Treatment

References

1.
Gray H. Anatomy of the Human Body. 20th ed. (Lewis WH, ed.). Lea & Febiger; 1918. https://www.bartleby.com/107/
2.
Kolar P. Clinical Rehabilitation. 1st ed. Dynamic Neurological Stabilization; 2014.

Citation

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