Diagram showing a few of the connections of afferent (sensory) fibers of the posterior root with the efferent fibers from the ventral column and with the various long ascending fasciculi. (Spinotectal fasciculus labeled at bottom right.)
Diagram of the principal fasciculi of the spinal cord. (Spinotectal fasciculus labeled at bottom left.)
The spinomesencephalic tract (spinotectal tract, spinotectal fasciculus, spino-quadrigeminal system of Mott) arises in the anterolateral column and terminate in the inferior and superior colliculi.
It is situated ventral to the lateral spinothalamic fasciculus, but its fibers are more or less intermingled with it.
In the brain-stem the fibers run lateral from the inferior olive, ventro-lateral from the superior olive, then ventro-medial from the spinal tract of the trigeminal; the fibers come to lie in the medial portion of the lateral lemniscus.