Fasciculus proprius lateralis

The proper fasciculi, or spinospinal fasciculi, or propriospinal tracts, are groups of short fibres, ascending and descending, and crossed and uncrossed, within the spinal cord.

These fibres are grouped into anterior, posterior, and lateral regions and make up a spinal pathway. Descending dorsal root collaterals are often included in the pathway.

There is an anterior fasciculus proprius, a lateral fasciculus proprius and a posterior pasciculus proprius.

The lateral proper fasciculus is made up of the remainder of the lateral column, and is continuous in front with the anterior proper fasciculus.

It consists chiefly of intersegmental fibres which arise from cells in the grey matter, and, after a longer or shorter course, re-enter the grey matter and ramify in it.

Some of its fibers are, also continued upward into the brain in the medial longitudinal fasciculus.