| nucleus dorsalis nervi vagi | The visceral motor nucleus located in the vagal trigone (ala cinerea) of the floor of the fourth ventricle. It gives rise to the parasympathetic fibres of the vagus nerve innervating the heart muscle and the smooth musculature and glands of the respiratory and intestinal tracts. Synonym: nucleus dorsalis nervi vagi, dorsal motor nucleus of vagus, dorsal nucleus of vagus, dorsal vagal nucleus, nucleus alae cinereae. (05 Mar 2000) |
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| nucleus nervi abducentis | Nucleus of abducent nervenucleus abducentis, a group of motor neurons in the lower part of the pons, innervating the lateral rectus muscle of the eye; unique among motor cranial nerve nuclei in that it consists of two distinct populations of neurons: neurons that give rise to fibres forming the abducens nerve root and those internuclear neurons whose processes cross the midline, ascend in the opposite medial longitudinal fasciculus, and terminate upon specific oculomotor neurons; considered a primary centre for mechanisms controlling conjugate horizontal gaze. Synonym: nucleus nervi abducentis. (05 Mar 2000) |
| nucleus nervi facialis | A group of motor neurons located in the ventrolateral region of the lower pontine tegmentum and innervating the facial muscles, the stapedius muscle in the middle ear, the posterior limb of the musculus digastricus, and the stylohyoid muscle. Synonym: nucleus nervi facialis, facial motor nucleus, motor nucleus of facial nerve, nucleus facialis. (05 Mar 2000) |
| nucleus nervi hypoglossi | The motor nucleus innervating the intrinsic and four of the five extrinsic muscles of the tongue; it is located in the medulla oblongata near the midline, immediately beneath the floor of the inferior recess of the rhomboid fossa. Synonym: nucleus nervi hypoglossi, nucleus of hypoglossal nerve. (05 Mar 2000) |
| nucleus nervi oculomotorii | The composite group of motor neurons innervating all of the external eye muscles except the musculus rectus lateralis and musculus obliquus superior, and including the musculus levator palpebrae superioris; the most rostral component of the nucleus is the Edinger-Westphal nucleus which innervates the musculi sphincter pupillae and ciliaris via the ciliary ganglion. The oculomotor nucleus lies in the rostral half of the midbrain, near the midline in the most ventral part of the central gray substance; fibres of the medial longitudinal fasciculus form its lateral borders. Synonym: nucleus nervi oculomotorii, nucleus of oculomotor nerve. (05 Mar 2000) |
| nucleus nervi trochlearis | A group of motor neurons innervating the superior oblique muscle of the contralateral eye. The nucleus lies in the caudal half of the midbrain, behind the oculomotor nucleus, in the most ventral part of the central gray substance, near the midline. Synonym: nucleus nervi trochlearis, nucleus of trochlear nerve. (05 Mar 2000) |
| nucleus spinalis nervi accessorii | spinal nucleus of accessory nerve |
| discus nervi optici | The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve. Because the retina at the optic disk has no photoreceptors there is a corresponding blind spot in the visual field. (12 Dec 1998) |
| trigonum nervi hypoglossi | A slight elevation in the floor of the inferior recess of the fourth ventricle, beneath which is the nucleus of origin of the twelfth cranial nerve. Synonym: trigonum nervi hypoglossi, eminentia hypoglossi, hypoglossal eminence, trigone of hypoglossal nerve, trigonum hypoglossi, tuberculum hypoglossi. (05 Mar 2000) |
| trigonum nervi vagi | A prominence in the floor of the inferior fovea of the fourth ventricle that overlies the dorsal motor nucleus of the vagus. Synonym: trigonum nervi vagi, ala cinerea, ashen wing, gray wing, trigone of vagus nerve, va'gi eminentia. (05 Mar 2000) |