fasciculus proprius anterior [TA], fasciculus proprius lateralis [TA], fasciculus proprius posterior [TA]; ascending and descending spinospinal association fiber systems of the spinal cord that lie in the anterior, lateral, and posterior funiculi at the gray matter-white matter interface. SYN: anterior fasciculus proprius [TA], lateral fasciculus proprius [TA], posterior fasciculus proprius [TA], ground bundles, intersegmental fasciculi, lateral proprius bundle, proper fasciculi.