| Trapezoid body | |
|---|---|
 Terminal nuclei of thecochlear 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 themedulla oblongata. 2.Cochlear nerve. 3.Accessory nucleus of acoustic nerve. 4.Tuberculum acusticum. 5. Efferent fibers of accessory nucleus. 6. Efferent fibers oftuberculum acusticum, forming thestriae medullares, with 6’, their direct bundle going to thesuperior 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.Lateral lemniscus. 11.Raphé. 12.Pyramidal tracts. 13.Fourth ventricle. 14.Inferior peduncle. | |
| Details | |
| Identifiers | |
| Latin | corpus trapezoideum |
| MeSH | D065833 |
| NeuroNames | 594 |
| NeuroLex ID | birnlex_707 |
| TA98 | A14.1.05.315 |
| TA2 | 5960 |
| FMA | 72487 |
| Anatomical terms of neuroanatomy | |
Thetrapezoid body orventral acoustic stria is a structure in thepontine tegmentum formed by thecrossing-over (decussation) of a portion of theefferent second-order fibers of theventral cochlear nucleus (anterior cochlear nucleus). After decussating, some of these fibres proceed to ascend in the contralaterallateral lemniscus to reach and terminate in the dorsal nucleus of lateral lemniscus, and inferior colliculus.[1]: 383
The trapezoid body is part of theauditory pathway. It is one of three distinct decussating second-order efferent fiber pathways of the cochlear nuclei (the other two being thedorsal acoustic striae, andintermediate acoustic striae).[1]: 383 Not all efferents of the cochlear nuclei decussate though; the partial decussation of the cochear nuclei afferents is thought to be functionally important for sound localization.[2]
The trapezoid body is formed by horizontally-oriented,commissural fibers[1]: 107 which are readily identifiable.[1]: 383
The fibres of the trapezoid body terminate (synapse) in the (contralateral):[1]: 383
It is situated in (the caudal portion of[2]) the ventralpontine tegmentum[1] at the level of the pontomedullary junction.[3] It is situated immediately dorsal/posterior to thepontine nuclei, and ventral/anterior to themedial lemnisci.[2]
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