FIGURE 1.

Median pictures of posterior column. Left; A median picture of posterior column. A, b, and c frames indicate a, b, and c fields. fg; fasciculus gracilis, fc; fasciculus cuneatus, pt; pyramidal tract. a field; Posterior median sulcus and fasciculi gracilis. In the middle of the fasciculi gracilis, a fine lineal structure continues from the posterior median sulcus to the 3/4th depth of fasciculi gracilis (arrow heads). It disappears at the portion indicated by an arrow. b field; Ventral fasciculi gracilis, central part of fasciculi cuneatus, and bilateral pyramidal tracts. Axons of right and left fasciculi fuse without boundary structures at the midline. c field; Ventral fasciculi cuneatus, bilateral pyramidal tracts and gray commissure. A triangular protrusion of glial tissue is noted at the commissure (arrow). It deviates a little from the commissure midline. A short fine lineal tissue (arrowhead) extends from the protrusion