fasciculus proprius posterior medullae spinalis

[TA] posterior fasciculus proprius of spinal cord: any of the bundles of white substance in the deepest part of the posterior funiculus of the spinal cord at the gray–white matter interface, consisting chiefly of intersegmental fibers derived from the cells of the posterior gray column, which divide into ascending and descending association fibers that reenter the gray substance and ramify in it. Called also dorsal or posterior intersegmental f. of spinal cord, dorsal f. proprius of spinal cord, and dorsal or posterior intersegmental tract of spinal cord.