The central representation area of the radial nerve in the goat, studied by the axon reaction.

The central representation area of the radial nerve has been investigated in the goat, using the axon reaction. The retrograde changes after a two or six weeks survival time have been used to study both its position and architecture. Reconstructions have been made using a computer assisted approach. In the goat the central representation area of the radial nerve is situated in the dorsolateral part of the lateral motoneuronal cell group, extending from caudal C6 to caudal T1. It begins very small in C6, enlarges through C7, reaches its maximal diameter in C8, from where it gradually decreases to end in caudal T1. The contribution of the C6 segment to the central representation area of the radial nerve in the goat is in agreement with findings in some other species but it contrasts with the macroscopic origin of the radial nerve in ruminants. It is suggested that this finding, together with the statistically significant reduction in the number of alpha motoneurons at the C6 level in calves affected with Arthrogryposis Multiplex Congenita (AMC) in the forelimbs, may prove an at least partial involvement of the radial nerve in the pathogenesis of this disease, which is also suggested by clinical symptoms.