The main sensory nucleus receives its afferents (as the sensory root) from the semilunar ganglion through the lateral part of the pons ventral surface. Its axons cross to the other side, ascending to the thalamic nuclei to relay in the postcentral cerebral cortex. The descending sensory fibers from the semilunar ganglion course through the pons and medulla in the spinal tract of CN V to end in the nuclei of this tract (as far as the second cervical segment). (See tables 1 and 2, below.)