The relation between size of motoneurons and their position in the cat spinal cord.

Experiments were performed to test whether motoneurons in the plantaris and medial gastrocnemius muscles of the cat are arranged in the spinal cord according to their sizes. It was found that motoneurons are randomly distributed with respect to size in their motor nuclei. Evidence is also presented that motoneuron density in these pools is irregular, and that there is considerable variability of position of medial gastrocnemius and plantaris motor pools from animal to animal.