Trapezoid body

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Brain: Trapezoid body

Terminal nuclei of the cochlear nerve, with their upper connections. (Schematic.) The vestibular nerve with its terminal nuclei and their efferent fibers have been suppressed. On the other hand, in order not to obscure the trapezoid body, the efferent fibers of the terminal nuclei on the right side have been resected in a considerable portion of their extent. The trapezoid body, therefore, shows only one-half of its fibers, viz., those that come from the left. 1. Vestibular nerve, divided at its entrance into the medulla oblongata. 2. Cochlear nerve. 3. Accessory nucleus of acoustic nerve. 4. Tuberculum acusticum. 5. Efferent fibers of accessory nucleus. 6. Efferent fibers of tuberculum acusticum, forming the striae medullares, with 6’, their direct bundle going to the superior olivary nucleus of the same side; 6’’, their decussating bundles going to the superior olivary nucleus of the opposite side. 7. Superior olivary nucleus. 8. Trapezoid body. 9. Trapezoid nucleus. 10. Central acoustic tract (lateral lemniscus). 11. Raphé. 12. Cerebrospinal fasciculus. 13. Fourth ventricle. 14. Inferior peduncle.
Latin corpus trapezoideum
Gray's p.858
NeuroNames hier-589
NeuroLex ID birnlex_707

The trapezoid body is part of the auditory pathway. It is a bundle of fibers and cells in the pontine tegmentum. It consists of fibers arising from the ventral cochlear nucleus. A collection of nerve cells inside forms a trapezoid nucleus. The superior olivary nucleus is situated on the dorsal surface of the trapezoid body. Most nerve fibers pass directly from the superior olivary nuclei to the inferior colliculus.

Axons leaving the ventral cochlear nucleus (VCN) form a broad pathway that crosses under the brain stem in the trapezoid body. A thin pathway, the intermediate acoustic stria, also leaves the VCN, merging with the trapezoid body close to the superior olivary complex, where many of its axons synapse. Axons leaving the dorsal cochlear nucleus (DCN) form the dorsal acoustic stria, which reaches primarily the contralateral dorsal nucleus of the lateral lemniscus and the central nucleus of the inferior colliculus.

Dorsal/
(tegmentum)
Surface
White: Sensory/ascending
White: Motor/descending
Grey: Cranial nuclei
afferent:
efferent:
Other grey
Ventral/
(base)
Grey
White: Motor/descending
Surface
Other grey: Raphe/
reticular

M: CNS

anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp

noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr

proc, drug (N1A/2AB/C/3/4/7A/B/C/D)

Auditory and vestibular pathways
Auditory
Vestibular

M: EAR

anat (e/p)/phys/devp

noco/cong, epon

proc, drug (S2)


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