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The all ulnar motor hand without forearm anastomosis
G M Sachs1, E M Raynor, J M Shefner
1Division of Neurology, Brigham and Women's Hospital Boston, Massachusetts.
Muscle & Nerve
|March 1, 1995
Summary
Rare cases of unusual ulnar nerve function in the hand were studied using nerve conduction tests. Findings suggest motor nerve connections between the ulnar and median nerves cause this anomaly.
Area of Science:
- Neuroscience
- Clinical Electrophysiology
Background:
- Anomalous ulnar innervation of intrinsic hand muscles is rarely documented electrophysiologically.
- Previous clinical studies suggested its occurrence, but empirical evidence was limited.
Observation:
- Two cases with predominantly ulnar innervation of hand muscles were evaluated.
- Near-nerve and standard nerve conduction studies were performed.
- No anomalous communication was found in the forearm.
Findings:
- Digital sensory fibers showed normal distribution in both median and ulnar nerves.
- Anomalous motor innervation was observed.
- The findings suggest palmar communication between ulnar and median nerve branches (Riche-Cannieu anastomoses).
Implications:
- The normal sensory distribution indicates these anastomoses primarily involve motor axons.
- This provides electrophysiological evidence for a specific type of peripheral nerve anomaly.
- Understanding these pathways is crucial for accurate diagnosis and treatment of hand neuropathies.