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Ulnar Nerve

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Ulnar nerve branching patterns at the elbow and wrist[1]
Anatomic course of the ulnar nerve[2]
Borders of the cubital tunnel[3]


  • One of the terminal branches of the brachial plexus
  • It is a continuation of the medial cord and contains fibres from spinal roots C8 and T1.
  • It has motor and sensory supply to the forearm and hand.

General Course

  • It runs medial to the axillary artery.
  • The ulnar nerve penetrates the medial fascial septum to enter the posterior compartment of the arm.
  • It runs posterior to the medial humeral epicondyle in the cubital tunnel.
  • It enters the hand via the ulnar canal (Guyon’s canal).
  • It terminates by giving rise to superficial and deep branches.

Cubital Tunnel

  • Fibro-osseous space located on the posteromedial aspect of the elbow
  • Transmits ulnar nerve into the forearm
  • Medial wall: medial epicondyle of the humerus
  • Lateral wall: olecranon of the ulna
  • Floor: elbow joint capsule, medial collateral ligament of the elbow
  • Roof: Ligament spanning between the medial epicondyle and olecranon


Muscular innervations

Sensory innervations

  • Palmar cutaneous branch innervates: the medial half of the palm.
  • Dorsal cutaneous branch innervates: the medial side of the dorsum of hand.
  • Superficial branch innervates: the anterior aspect of the ulnar 1½ digits (little finger and half of the ring finger).

Clinical Significance

See Also


  1. Andrews, Kyle, et al. "Cubital tunnel syndrome: anatomy, clinical presentation, and management." Journal of orthopaedics 15.3 (2018): 832-836.
  2. Image courtesy of medbullets.com
  3. Image courtesy of teachmeanatomy.info, "The Ulnar Tunnel"
  4. Standring, Susan, and Henry Gray. 2008. Gray's anatomy: the anatomical basis of clinical practice
Created by:
Alaa Khader on 23 May 2022 21:57:38
Last edited:
26 June 2024 15:25:52