The spinal trigeminal nucleus of mammals has similar morphological characteristics. Its caudal partis continuous with the tip of the posterior horn of the cervical spinal cord. On the basis of the cytoar-chitecture

the spinal trigeminal nucleus may be divided into three parts: the spinal caudal

the spinalinterpolar and the spinal oral nuclei. The spinal trigeminal nucleus of the rabbit consists of the caudaland the oral parts only. The spinal caudal trigeminal nucleus is subdivided into three parts

namely

the subnucleus zonalis

the subnucleus gelatinosus and the subnucleus magnocellularis

corresponding re-spectively to the Rexed Ⅰ

Ⅱ and Ⅲ

Ⅱ layers of the posterior horn. The spinal trigeminal nucleusassociates mainly with pain and the temperature sensation of the cephalo-facial origin

and lakes part inthe processing of facial acupuncture analgesia. The spinal caudal trigeminal nucleus receives afferent fibers from the trigeminal nerve

the facialnerve

the glossopharyngeal nerve

the vague nerve

the reticular formation of the brain stem

the raphemagnus nucleus

the locus coeruleus

the cerebral cortex and the spinal cord: the efferent fibers fromthis nucleus project into the ventroposterior medial nucleus and the intralaminar nucleus of the thalmus

the medial geniculate body

the reticular formation of the brain stem

and some cranial nerve nuclei(the solitary tract nucleus

the principal sensory nucleus of the trigeminal nerve

the vestibular nucleus

the hypoglossal nucleus

the dorsal vagal nucleus

the ambiguous nucleus

the motor trigeminal nucleus

the facial nucleus and the oculomotor nucleus)

and also project into non-cranial nerve nuclei (theraphe magnus nucleus

the tectum of the midbrain

periaqueductal gray matter

the cuneatus nucleus

the cuneatus lateral and the medial accessary olivary nuclei

etc) and the upper cervical spinal cord. The primary afferent fibers and the spinal caudal nucleus of the trigeminal nerve are associated with many nuclei in the central nervous system

to which the somatic or visceral afferent fibers from differentportions converge. This direct convergence may be considered as the anatomical basis for the facialacupuncture impulses acting on the somatic or the visceral pain impulses in the same portion. The fiberconnections of the spinal caudal trigeminal nucleus with the spinal cord

the gigantocellular reticularnucleus

the raphe magnus nucleus and the intralaminar nucleus of thalamus probably provide the neuralbasis for facial acupuncture analgesia and for the operations on other parts of body performed under thefacial acupuncture analgesia. The fiber connections of this nucleus with the gigantocellular nucleus

thesolitary tract nucleus and the dorso-lateral reticular formation of the medulla oblongata perhaps providethe anatomical explanation for the facial acupuncture inhibiting the visceral pain and the visceral trac-tive response

which may be very important in supporting Integument-Visera correlation theory.