RECONSTRUCTION OF TRAJECTORY OF PRIMARY AFFERENT COLLATERALS IN DORSAL HORN OF CAT SPINAL-CORD, USING GOLGI-STAINED SERIAL SECTIONS

Using Golgi‐stained serial sections obtained at the sacro‐caudal levels of the cat spinal cord, it was possible to reconstruct the trajectory of primary afferents. They were classified into two groups: reliable primary afferents directly traced from the dorsal root and probable primary afferents traced from the dorsal funiculus or Lissauer's tract. The diameters of the reliable primary afferents vary from 0.88–1.88 μm. According to their courses, reliable primary afferents as well as probable primary afferents were classified into three groups: the first is distributed to both medial and lateral halves of the dorsal horn, the second to the medial half, and the third to the lateral half. Commissural fibers were also observed among the probable primary afferents. The rostro‐caudal and medio‐lateral extents of reliable primary afferents are found to be between 250 and 950 μm and 270 and 700 μm respectively, while those of the probable primary afferents were between 125 and 670 μm and 270 and 1,640 μm respectively. These primary afferent fibers are connected with at least two or more laminae of the dorsal horn gray matter. Copyright © 1978 The Wistar Institute Press