OBSERVATIONS ON THE NEURONS IN THE SPINAL VENTRAL ROOTS OF THE INFANTS / 解剖学报

ABSTRACT

Spinal ventral roots of 10 infants were examined. Eight pairs of spinal ventral roots were cut off from 10 infant cadavers including the following segments C_6, C_7,T_5, T_(11), L_3, L_5, S_1, and S_2. Serial longitudenal sections were prepared and stained with Niss's method. The presence of sensory neurons were recorded and their num- ber were counted. The results were as followsNerve cells in the spinal ventral roots were found in all the cases examined.The minimal number was 58 cells in No. 8, and the maximal number was 203 in No. 10. There were altogether 1,446 cells found in 117 spinal roots, and no cell in 35 roots. The highest number of nerve cells observed in a single root was 83.The nerve cells were scattered all over the spinal ventral root from its attachment to the spinal cord to its junction with the dorsal root. More cells were found in its distal extremity close to the spinal ganglion. They appeared singly, in groups of two or three, or in a cluster looking like a small ganglion. They were usually distributed among the nerve fibers, or around the blood vessels, or beneath the epineurium of the ventral root. They were ovoid in shape, with the long axis paralleling the course of nerve fibers. Nuclei were round in shape, Nissl granules were evenly distributed in the cytoplasm. They were different in sizes, ranging from 15 to 60 ?m. There were 808 cells (56%) more than 30～50 ?m. 607 cells (42%) less than 30 ?m, which accounted 98% of the total cell population.