Popis: |
Objective: Determination of muscles role innervated by median, ulnar and radial nerves in compound muscle action potential (CMAP) formation from the anterior forearm muscles at Erb’s point stimulation. Methods: Seventeen patients with radial nerve neuropathy in the spiral groove and seven patients with complete radial nerve injury were studied. Control group was consisted of eight healthy subjects and patients with undamaged side. CMAP was recorded from the anterior forearm muscles. Stimulation was performed at: (1) the antecubital fossa (median nerve); (2) the distal part of the medial brachium (median and ulnar nerves); (3) the distal part of the lateral brachium (radial nerve); (4) the elbow (ulnar nerve); (5) Erb’s point or the axilla (proximal point). Negative phase area was measured. Results: In control group the 1st CMAP area was 71.9%, the 2nd one – 73.0%, the 3rd – 22.8%, the 4th CMAP area – 13.6% according to proximal CMAP area. In patients with radial nerve neuropathy percentage of the 1st and 2nd CMAP area to the proximal CMAP increased to 93.5% and 97.7% (p 0.05), respectively. In patients with complete injury of the radial nerve negative CMAP area at the 1st point stimulation was 85.1%, the 2nd – 96.9%, the 4th – 25.5% to the proximal CMAP. No significance difference between the 1st and the 2nd valueswas revealed in all groups. Conclusion: Median nerve and radial one in less level make an important contribution to the CMAP formation recorded from the anterior forearm muscles at Erb’s point stimulation. It is important for estimation of nerves function at the proximal segment in patients with multifocal motor neuropathy and other diseases with marked axonal damage of distal muscles. |