myelencephalon


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

myelencephalon

 [mi″el-en-sef´ah-lon]
1. the posterior part of the rhombencephalon, comprising the medulla oblongata and lower part of the fourth ventricle.
2. the posterior of the two brain vesicles formed by specialization of the rhombencephalon in the developing embryo.

me·dul·la ob·lon·ga·'ta

[TA]
the most caudal subdivision of the brainstem, immediately continuous with the spinal cord, extending from the lower border of the decussation of the pyramid to the pons; its anterior (ventral) surface resembles that of the spinal cord except for the bilateral prominence of the inferior olive; the posterior (dorsal) surface of its upper half forms part of the floor of the fourth ventricle. Motor nuclei of the medulla oblongata include the hypoglossal nucleus, the dorsal motor nucleus, inferior salivatory nucleus, and the nucleus ambiguus; sensory nuclei include the nuclei of the posterior column (gracile and cuneate), the cochlear and vestibular nuclei, the middle and caudal portions of the spinal trigeminal nucleus, and the nucleus of the solitary tract.
See also: medulla.
Synonym(s): myelencephalon [TA], oblongata

myelencephalon

/my·el·en·ceph·a·lon/ (-en-sef´ah-lon)
2. the posterior of two brain vesicles formed by specialization of the rhombencephalon in embryonic development.

myelencephalon

(mī′ə-lĕn-sĕf′ə-lŏn′)
n.
1. The posterior portion of the embryonic hindbrain, from which the medulla oblongata develops.
2. The medulla oblongata of the adult brain.

my′e·len·ce·phal′ic (-sə-făl′ĭk) adj.

myelencephalon

[mī′əlensef′əlon]
the lower part of the embryonic hindbrain, from which the medulla oblongata develops.

myelencephalon

The posterior part of the hindbrain (rhombencephalon) in the embryo, which differentiates into the medulla oblongata, the caudal end of the fourth ventricle and cranial nerves 8 to 12.

me·dul·la ob·lon·ga·ta

(mĕ-dŭl'ă ob-long-gā'tă) [TA]
The most caudal subdivision of the brainstem, continuous with the spinal cord, extending from the lower border of the decussation of the pyramid to the pons; its ventral surface resembles that of the spinal cord except for the bilateral prominence of the inferior olive; the dorsal surface of its upper half forms part of the floor of the fourth ventricle. Motor nucleiof the medulla oblongata include the hypoglossal nucleus, the dorsal motor nucleus, inferior salivatory nucleus, and the nucleus ambiguus; sensory nuclei include the nuclei of the posterior column (gracile and cuneate), the cochlear and vestibular nuclei, the mid and caudal portions of the spinal trigeminal nucleus, and the nucleus of the solitary tract.
See also: medulla
Synonym(s): myelencephalon, oblongata.

myelencephalon

1. the part of the central nervous system comprising the medulla oblongata and caudal of the fourth ventricle.
2. the posterior of the two brain vesicles formed by specialization of the rhombencephalon in the developing embryo.