Origin of lingual proprioceptive afferents in Japanese monkey, M. fuscata fuscata. Studied by HRP-labeling technique.

The peripheral course of the axon of the lingual proprioceptive neurons in 5 Japanese monkeys was studied by injecting HRP into the distal part of the hypoglossal nerve through the proximal stump. The present authors confirmed that the HRP-labeled cell bodies appeared ipsilaterally in the C2, C3 and C4 spinal ganglia. The afferents to the C2, C3 and C4 ganglia pass through the ansa hypoglossi and direct neuronal anastomosis existing between the first cervical nerve and the hypoglossal nerve. It was confirmed that in the Japanese monkey, having abundant muscle spindles in the tongue, the lingual proprioceptive neuron soma exist in the C2, C3 and C4 spinal ganglia, their peripheral axons passing through the ansa hypoglossi and the direct neuronal anastomosis.