Posterior antebrachial cutaneous nerve conduction studies in normal subjects

The posterior antebrachial cutaneous (PABC) nerve is a sensory nerve that branches out from the radial nerve at the level of the spiral groove. Thus it can be affected in a radial nerve lesion at or proximal to its origin in the spiral groove. However, there has been limited knowledge about the normal values of PABC nerve conduction studies. This study was done to determine these normal values.Sixty-three healthy adults (23 males) with a mean age of 41.5+/-10.6 (range, 20-90) years were recruited with informed consent. A total of 126 nerves were studied. The nerve conduction studies were performed using a Dantec Counterpoint EMG machine (Dantec, Skovlunde, Denmark).The mean+/-standard deviation values for the onset as well as peak latency, conduction velocity, amplitude and side-to-side amplitude ratio were 2.07+/-0.16 (range, 1.80-2.60) ms, 2.35+/-0.15 (range, 2.05-2.90) ms, 58.21+/-4.29 (range, 46.15-66.67) m/s, 6.10+/-2.11 (range, 2.90-13.00) microV and 0.83+/-0.12 (range, 0.60-0.99), respectively. There was a significant correlation between the subject age and the PABC onset and peak latencies as well as the amplitudes.The PABC nerve is assessable for nerve conduction studies and these normal values may be useful in evaluation of patients with suspected radial nerve lesions.