| descending tract of trigeminal nerve | <anatomy, nerve> A compact fibre bundle, comma-shaped on transverse section, composed of primary sensory fibres of the portio major of the trigeminal nerve, descending from the level of the entrance of the trigeminus in the upper pons down through the dorsolateral region of the rhombencephalic tegmentum along the lateral side of the descending or spinal nucleus of the trigeminus, emerging on the dorsolateral surface of the lower medulla oblongata as the tuberculum cinereum, and continuing as far as the second cervical segment of the spinal cord. Its fibres are distributed to the descending or spinal nucleus of the trigeminus. Synonym: tractus spinalis nervi trigemini, descending tract of trigeminal nerve, tractus descendens nervi trigemini. (05 Mar 2000) |
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| trigeminal | <anatomy> Of, pertaining to, or designating, the fifth pair of cranial nerves, which divide on each side of the head into three main branches distributed to the orbits, jaws, and parts of the mouth; trifacial. See: Trigeminous. Source: Websters Dictionary (01 Mar 1998) |
| trigeminal caudal nucleus | The caudal portion of the nucleus of the spinal trigeminal tract (trigeminal nucleus, spinal), a nucleus involved with pain and temperature sensation. (12 Dec 1998) |
| trigeminal cave | The cleft in the meningeal layer of dura of the middle cranial fossa near the tip of the petrous part of the temporal bone; it encloses the roots of the trigeminal nerve and the trigeminal ganglion. Synonym: cavum trigeminale, Meckel's cavity, Meckel's space, trigeminal cavity. (05 Mar 2000) |
| trigeminal cavity | The cleft in the meningeal layer of dura of the middle cranial fossa near the tip of the petrous part of the temporal bone; it encloses the roots of the trigeminal nerve and the trigeminal ganglion. Synonym: cavum trigeminale, Meckel's cavity, Meckel's space, trigeminal cavity. (05 Mar 2000) |
| trigeminal crest | That part of the cranial neural crest from which the ganglion of the fifth cranial nerve develops. (05 Mar 2000) |
| trigeminal decompression | Decompression of the trigeminal nerve root. (05 Mar 2000) |
| trigeminal ganglion | The semilunar-shaped ganglion containing the cells of origin of most of the sensory fibres of the trigeminal nerve. It is situated within the dural cleft on the cerebral surface of the petrous portion of the temporal bone and gives off the ophthalmic, maxillary, and part of the mandibular nerves. (12 Dec 1998) |
| trigeminal impression | A depression on the anterior surface of the petrous portion of the temporal bone, near the apex, lodging the trigeminal ganglion. Synonym: impressio trigeminalis. (05 Mar 2000) |
| trigeminal lemniscus | Collective term denoting the fibres ascending from the sensory nucleus of the trigeminus; one such fibre system originates from the main sensory nucleus, largely decussates, and ascends as the ventral trigeminal lemniscus to join the medial lemniscus with which it enters the ventral posterior nucleus of thalamus, terminating in the mediodorsal region of that nucleus; a second, uncrossed, fibre group follows an ascending course through central parts of the mesencephalic tegmentum ("dorsal trigeminal lemniscus"). The trigeminal lemniscus conveys tactile, pain, and temperature impulses from the skin of the face, the mucous membranes of the nasal and oral cavities, and the eye, as well as proprioceptive information from the facial and masticatory muscles. Synonym: lemniscus trigeminalis. (05 Mar 2000) |
| trigeminal nerve | <anatomy, nerve> The trigeminal nerve is responsible for sensory enervation of the face and motor enervation to muscles of mastication (chewing). There are three divisions of the fifth cranial nerve, ophthalmic, maxillary and mandibular. Lesions of the sensory root to the trigeminal nerve can result in pain or loss of sensation in the face. Lesion of the motor root result in deviation of the jaw toward the paralysed side and difficulty chewing. Synonym: cranial nerve V. (27 Sep 1997) |
| trigeminal neuralgia | <neurology> A disorder of trigeminal nerve (cranial nerve V) dysfunction. Synonym: tic douloureux. Characterised by excruciating paroxysms of pain in the lips, gums, cheek or chin, and, very rarely, in the distribution of the eye (ophthalmic division of the trigeminal nerve). (27 Sep 1997) |
| trigeminal nuclei | Nuclei of the trigeminal nerve situated in the brainstem. They include the nucleus of the spinal trigeminal tract (trigeminal nucleus, spinal), the principal sensory nucleus, the mesencephalic nucleus, and the motor nucleus. (12 Dec 1998) |
| trigeminal nucleus, spinal | Nucleus of the spinal tract of the trigeminal nerve. It is divided cytoarchitectonically into three parts: oralis, caudalis (trigeminal caudal nucleus), and interpolaris. (12 Dec 1998) |
| trigeminal pulse | A pulse in which the beats occur in trios, a pause following every third beat. Synonym: pulsus trigeminus. (05 Mar 2000) |