The spinal nucleus is composed of three subnuclei: subnucleus oralis (pars oralis), subnucleus caudalis (pars caudalis), and subnucleus interpolaris (pars interpolaris). The subnucleus oralis is associated with the transmission of discriminative (fine) tactile sense from the orofacial region, and is continuous with the principal sensory nucleus of V. The subnucleus interpolaris is also associated with the transmission of tactile sense, as well as dental pain, whereas the subnucleus caudalis is associated with the transmission of nociception and thermal sensations from the head.