| transverse crest of internal acoustic meatus | A horizontal ridge that divides the fundus of the internal acoustic meatus into a superior and an inferior area. In the former are the introitus of the facial canal and openings for the branches of the vestibular nerve to the utricle and to the ampullae of the anterior and lateral saemicircular canals. In the latter are openings for the cochlear nerve, and for branches of the vestibular nerve to the saccule and to the ampulla of the posterior saemicircular canal. Synonym: crista transversa, falciform crest, transverse crest. (05 Mar 2000) |
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| external acoustic foramen | The orifice of the external acoustic meatus in the tympanic portion of the temporal bone. Synonym: porus acusticus externus, external acoustic foramen, external acoustic pore, external auditory pore, external auditory foramen, orifice of external acoustic meatus. (05 Mar 2000) |
| external acoustic meatus | The passage leading inward through the tympanic portion of the temporal bone, from the auricle to the tympanic membrane; it consists of a bony (inner) portion and a fibrocartilaginous (outer) portion, the cartilaginous external acoustic meatus. Synonym: meatus acusticus externus, acoustic meatus, antrum auris, auditory canal, external auditory meatus. (05 Mar 2000) |
| external acoustic pore | The orifice of the external acoustic meatus in the tympanic portion of the temporal bone. Synonym: porus acusticus externus, external acoustic foramen, external acoustic pore, external auditory pore, external auditory foramen, orifice of external acoustic meatus. (05 Mar 2000) |
| fundus of internal acoustic meatus | The thin cribriform plate of bone separating the cochlea and vestibule from the internal acoustic meatus; a transverse crest divides it into two regions; in the superior region are located the area nervi facialis and the area vestibularis superior; in the inferior region are located the area cochleae, area vestibularis inferior, and foramen singulare. Synonym: fundus meatus acustici interni, fundus of internal auditory meatus. (05 Mar 2000) |
| accessory olivary nuclei | See: dorsal accessory olivary nucleus, medial accessory olivary nucleus. (05 Mar 2000) |
| anterior nuclei of thalamus | Collective term for three groups of nerve cells which together form the anterior thalamic tubercle: the anteroventral nuclei, a relatively large nucleus; the anteromedial nuclei; and the anterodorsal nuclei, a small (but large-celled) nucleus. The nuclei receive the mamillothalamic tract from the mamillary body, and additional afferents by way of the fornix; they project collectively to the cortex of the cingulate and parahippocampal gyrus. Synonym: nuclei anteriores thalami. (05 Mar 2000) |
| arcuate nuclei | A variable assembly of small cell groups, probably outlying components of the pontine nuclei, on the ventral and medial aspects of the pyramid in the medulla oblongata. Synonym: nuclei arcuati. (05 Mar 2000) |
| autonomic nuclei | Nuclei located in the spinal cord (T1-L2, S2-S4) and in the brainstem (Edinger-Westphal nucleus, superior and inferior salivatory nuclei, dorsal vagal nucleus and parts of the ambiguus nucleus) from which general visceral efferent preganglionic fibres arise; may be sympathetic (T1-L2) or parasympathetic (craniosacral); hypothalamic nuclei/areas function in concert with autonomic nuclei. (05 Mar 2000) |
| basal nuclei | Nucleus of the cerebral hemisphere that originally included the caudate and lenticular nuclei, the claustrum and the amygdaloid body (complex); functionally the term basal nuclei now specifies the caudate and lenticular nuclei and adjacent cell groups having important connections therewith (subthalamic nucleus; substantia nigra, partes compacta and reticulata); amygdaloid complex now known to be part of the limbic system. Synonym: nuclei basales. (05 Mar 2000) |
| branchiomotor nuclei | Collective term for those motoneuronal nuclei of the brainstem (n. Ambiguus, facial motor nucleus, motor nucleus of the trigeminus) that develop from the branchiomotor column of the embryo and innervate striated muscle fibres (muscles of mastication, facial musculature, pharynx and vocal cord muscles) developed from the mesenchyme of the branchial arches. Synonym: special visceral efferent nuclei, special visceral motor nuclei. (05 Mar 2000) |
| caput nuclei caudati | The head or anterior extremity of the caudate nucleus projecting into the anterior horn of the lateral ventricle. Synonym: caput nuclei caudati, anterior extremity of caudate nucleus. (05 Mar 2000) |
| rami caudae nuclei caudati | Branches to the tail of the caudate nucleus. Branches from either the anterior choroid or the posterior communicating artery, or both, to supply the tail of the caudate nucleus, a branch from the middle cerebral artery to the tail of the caudate nucleus. (05 Mar 2000) |
| venae nuclei caudati | Small veins from the caudate nucleus draining into the superior thalamostriate vein. Synonym: veins of caudate nucleus. (05 Mar 2000) |
| parabrachial nuclei | The cell groups flanking the brachium conjunctivum at levels immediately caudal to the inferior colliculus; they serve as way-stations in the pathways ascending from the nucleus of solitary tract to the thalamus and hypothalamus, and receive afferent fibres from the hypothalamus and amygdaloid body. Synonym: nuclei parabrachiales. (05 Mar 2000) |