Ulnar Nerve
Description
General[4]
- 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.
- 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
- Flexor Carpi Ulnaris
- Hypothenar Muscles
- Flexor Digitorum Profundus
- Medial two Lumbricals
- Adductor pollicis
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).
Branches
- Superficial Branch of the Ulnar Nerve
- Motor: Palmaris Brevis
- Sensory: ulnar side of 4th digit, entire 5th digit
- Deep Branch of the Ulnar Nerve
- Motor: hypothenar muscles, palmar interossei, dorsal interossei, medial two lumbricals, deep head of flexor pollicis brevis, adductor pollicis
- Sensory: minimal
- Dorsal Cutaneous Branch of the Ulnar Nerve
- Sensory branch of the ulnar nerve that provides sensation to the dorsal hand
Anatomic Variants
- Richie-Cannieu Communication
- Communication in the palm between
- recurrent branch of the median nerve
- Deep branch of the ulnar nerve
- Martin Gruber Anastomosis
- Approximately 15% of patients have a motor communication between the median and ulnar nerves[5]
Clinical Significance
See Also
References
- ↑ Andrews, Kyle, et al. "Cubital tunnel syndrome: anatomy, clinical presentation, and management." Journal of orthopaedics 15.3 (2018): 832-836.
- ↑ Image courtesy of medbullets.com
- ↑ Image courtesy of teachmeanatomy.info, "The Ulnar Tunnel"
- ↑ Standring, Susan, and Henry Gray. 2008. Gray's anatomy: the anatomical basis of clinical practice
- ↑ Slutsky, David J., ed. Upper extremity nerve repair-tips and techniques: a master skills publication. Amer Soc Of Surgery of the Hand, 2008.
Created by:
Alaa Khader on 23 May 2022 21:57:38
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Last edited:
17 September 2025 20:02:38
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