The development of the neural crest in the human

Abstract

The first systematic account of the neural crest in the human has been prepared after an investigation of 185 serially sectioned staged embryos, aided by graphic reconstructions. As many as fourteen named topographical subdivisions of the crest were identified and eight of them give origin to ganglia (Table 2). Significant findings in the human include the following. (1) An indication of mesencephalic neural crest is discernible already at stage 9, and trigeminal, facial, and postotic components can be detected at stage 10. (2) Crest was not observed at the level of diencephalon 2. Although pre-otic crest from the neural folds is at first continuous (stage 10), crest-free zones are soon observable (stage 11) in Rh.1, 3, and 5. (3) Emigration of cranial neural crest from the neural folds at the neurosomatic junction begins before closure of the rostral neuropore, and later crest cells do not accumulate above the neural tube. (4) The trigeminal, facial, glossopharyngeal and vagal ganglia, which develop from crest that emigrates before the neural folds have fused, continue to receive contributions from the roof plate of the neural tube after fusion of the folds. (5) The nasal crest and the terminalis-vomeronasal complex are the last components of the cranial crest to appear (at stage 13) and they persist longer. (6) The optic, mesencephalic, isthmic, accessory, and hypoglossal crest do not form ganglia. Cervical ganglion 1 is separated early from the neural crest and is not a Froriep ganglion. (7) The cranial ganglia derived from neural crest show a specific relationship to individual neuromeres, and rhombomeres are better landmarks than the otic primordium, which descends during stages 9-14. (8) Epipharyngeal placodes of the pharyngeal arches contribute to cranial ganglia, although that of arch 1 is not typical. (9) The neural crest from rhombomeres 6 and 7 that migrates to pharyngeal arch 3 and from there rostrad to the truncus arteriosus at stage 12 is identified here, for the first time in the human, as the cardiac crest. (10) The hypoglossal crest provides cells that accompany those of myotomes 1-4 and form the hypoglossal cell cord at stages 13 and 14. (11) The occipital crest, which is related to somites 1-4 in the human, differs from the spinal mainly in that it does not develop ganglia. (12) The occipital and spinal portions of the crest migrate dorsoventrad and appear to traverse the sclerotomes before the differentiation into loose and dense zones in the latter. (13) Embryonic examples of synophthalmia and anencephaly are cited to emphasize the role of the neural crest in the development of cranial ganglia and the skull.

Early development of the facial nerve in human embryos at stages 13–15

“…The important structure during the development of the nervous system is the neural crest which gives rise to variety of derivatives including the spinal and cranial ganglia [28]. In human embryos, the neural crest is indicated first at stage 9 in mesencephalic neuromere.…”

“…The sensory nuclei of the cranial nerves develop in the common afferent tract [6,11,20,28]. The motor nucleus of the facial nerve in all investigated stages is medially to the abducent nucleus in the future dorsomedial nuclear column.…”

“…Recently O'Rahilly and Müller [27,28] studied the development of the cranial nerves in human embryos. They were concerned mainly with the neuronal migration, formation of the nuclei in the brain stem and sequence of appearance of the cranial nerves.…”

Development of the Juxta‐Oral Organ in Rat Embryo

“…It has been reported that in rats the cranial ganglia and nerves were HNK-1 positive (Louryan et al, 1996;Nagase et al, 2003). Thus, in human (O'Rahilly and Mü ller, 2007) and chicken embryos (Shigetani et al, 2008), it has been reported that the trigeminal ganglion originated from the neural crest and from the trigeminal placode (Knabe et al, 2009). Probably, the parts of the trigeminal ganglion that originate from the trigeminal placode correspond to the parts that were HNK-1 negative.…”

Neural Tube Defects and Associated Congenital Malformations in Intrauterine Dead and Stillborn Foetuses- A Cross-Sectional Study

“…14 It is found that frontal, parietal, squamous part of temporal bones and upper part of occipital squama are developed from neural crest. 15 Neural tube defects occur due to failure of mutual induction of germ layers in related sequence. Disturbances of inductive events involved in primary neurulation leads to various errors of neural tube closure followed by alterations of axial skeleton as well as overlying meningovascular and dermal coverings.…”