Summary
Twenty embryos of stage 11 (24 days) were studied in detail and graphic reconstructions of twelve of them were prepared. The characteristic feature of this stage is 13–20 pairs of somites.
The notochord sensu stricto appears first during this stage, and its rostral and caudal parts differ in origin. Rostrally, the notochordal plate is being transformed into the notochord in a caudorostral direction. The caudal part, however, arises from the axial condensation in the caudal eminence in a rostrocaudal direction. The caudal eminence (or end bud) represents the former primitive streak. The somites are increasing in number at a mean rate of 6.6 h per pair.
The rostral neuropore closes towards the end of stage 11. The closure is basically bidirectional, being more rapid in the roof region and producing the embryonic lamina terminalis and future commissural plate in the basal region. The caudal neuropore is constantly open. The brain comprises telencephalon medium (represented by the embryonic lamina terminalis) and a series of neuromeres: 2 for the forebrain (D1 and D2), 1 for the midbrain, and 6–7 for the hindbrain (RhA-C; Rh D is not clearly delineated). The forebrain still occupies a small proportion of the total brain, whereas the spinal part of the neural tube is lengthening rapidly. Some occlusion of the lumen of the neural tube was noted in 4 embryos, all of which had an open rostral neuropore. Hence there is at present no evidence that occlusion plays a role in expansion of the human brain. The marginal (primordial plexiform) layer is appearing, particularly in rhombomere D and in the spinal portion of the neural tube. The neural crest is still forming from both the (open) neural groove and the (closed) neural tube, and exclusively from both neural (including optic) and (mainly) otic ectoderm.
The optic sulcus is now prominent, and its wall becomes transformed into the optic vesicle towards the end of stage 11. At this time also, an optic sheath derived from mesencephalic crest and optic crest is present. The mitotic figures of the optic neural crest are exceptional in being situated in the external part of the neural epithelium. The otic pit is becoming deeper, and its wall is giving rise to neural crest that is partly added to the faciovestibulocochlear ganglion and partly forms an otic sheath. The nasal plate does not yet give off neural crest.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Abbreviations
- B :
-
Endoderm rostral to neurenteric canal or its site
- A-H :
-
Primordium of adenohypophysis
- All :
-
Allantoic primordium
- Ao :
-
Aorta
- C.E. :
-
Caudal eminence (caudal bud, end bud)
- Caud.lim.S. :
-
Caudal limiting sulcus
- Ch. :
-
Chiasmatic plate
- D :
-
Diencephalon
- F :
-
Foregut, pharynx
- Cl. :
-
Cloacal membrane
- Ggl :
-
Ganglion
- H :
-
Hindgut
- I :
-
Infundibulum
- L.T. :
-
embryonic lamina terminalis
- M :
-
Mamillary area
- Mes. :
-
Mesencephalon, mesencephalic
- Mit. :
-
Mitotic figure
- Nas. :
-
Nasal plate
- N.C. :
-
Site of neurenteric canal
- N.Cr. :
-
Neural crest
- Not.Pl. :
-
Notochordal plate
- Not. :
-
Notochord
- O-Ph :
-
Oropharyngeal membrane
- Opt. :
-
Optic primordium
- Opt.S. :
-
Optic sulcus
- Ot. :
-
Otic pit
- Ot.sh. :
-
Otic sheath
- Ph.Ar. :
-
Pharyngeal arch
- Pr. :
-
Mesenchyme of prechordal plate
- Pros. :
-
Prosencephalon
- Rec. :
-
Postoptic recess
- Resp. :
-
Respiratory primordium
- Rh :
-
Rhombomere
- S.V. :
-
Sinus venosus
- s. :
-
Somite
- Tel. :
-
Telencephalon
- Th. :
-
Chickening
- Thyr. :
-
Thyroid primordium
- Trig. :
-
Trigeminal
- X :
-
Cau
- al :
-
neuropore
- Y :
-
Rostral neuropore
References
Bartelmez GW (1923) The subdivision of the neural folds in man. J Comp Neurol 35:231–247
Bartelmez GW (1962) The proliferation of neural crest from forebrain levels in the rat. Contrib Embryol Carnegie Inst 37:1–12
Bartelmez GW, Blount MP (1954) The formation of neural crest from the primary optic vesicle in man. Contrib Embryol Carnegie Inst 35:55–71
Bartelmez GW, Dekaban AS (1962) The early development of the human brain. Contrib Embryol Carnegie Inst 37:13–32
Bartelmez GW, Evans HM (1926) Development of the human embryo during the period of somite formation, including embryos with two to sixteen pairs of somites. Contrib Embryol Carnegie Inst 17:1–67
Bellairs R (1985) A new theory about somite formation in the chick. In: Lash JW, Saxén L (eds) Developmental mechanisms: Normal and abnormal. Alan R. Liss, New York, pp 25–44
Bergquist H (1952) Formation of neuromeres in homo. Acta Soc Med 57:23–32
Bretos M (1979) La morphogénèse primordiale du ganglion statoacoustique et de l'oreille interne chez l'embryon de souris. I. Analyse de la morphogénèse précoce chez les embryons de 9, 9 1/2 et 10 jours. Arch Biol 90:195–224
Bujard E (1914) Description d'un embryon humain (Eternod-Delaf.), de 20 somites, avec flexion dorsale. Int Monatsschr Anat Physiol 31:238–266
Butcher EO (1929) The development of the somites in the white rat (Mus norvegicus albinus) and the fate of the myotomes, neural tube, and gut in the tail. Am J Anat 44:381–439
Couly GF, Le Douarin NM (1985) Mapping of the early neural primordium in quail-chick chimeras. I. Developmental relationships between placodes, facial ectoderm and prosencephalon. Dev Biol 110:422–429
Davis CI (1923) Description of a human embryo having twenty paired somites. Contrib Embryol Carnegie Inst 15:1–51
Dekaban AS (1963) Anencephaly in early human embryos. J Neuropathol Exp Neurol 22:533–548
Dekaban AS, Bartelmez GW (1964) Complete dysraphism in 14 somite human embryo. Am J Anat 115:27–41
Deol MS (1967) The neural crest and the acoustic ganglion. J Embryol Exp Morphol 17:533–541
Deol MS (1970) The origin of the acoustic ganglion and effects of the gene dominant spotting (Wv) in the mouse. J Embryol Exp Morphol 23:773–784
Desmond ME (1982) Description of the occlusion of the spinal cord lumen in early human embryos. Anat Rec 204:89–93
Desmond ME, O'Rahilly R (1981) The growth of the human brain during the embryonic period proper. I. Linear axes. Anat Embryol 162:137–151
Desmond ME, Schoenwolf GC (1985) Timing and positioning of occlusion of the spinal neurocele in the chick embryo. J Comp Neurol 235:479–487
Gilbert PW (1957) The origin and development of the human extrinsic ocular muscles. Contrib Embryol Carnegie Inst 36:59–78
Goedbloed JF, Smits-van-Proije AE (1986) Quantitative analysis of the temporal pattern of somite formation in the mouse and rat. A simple and accurate method for age determination. Acta Anat 125:76–82
Goodrum GR, Jacobson AG (1981) Cephalic flexure formation in the chick embryo. J Exp Zool 216:399–408
Gribnau AAM, Geijsberts LGM (1981) Developmental stages in the rhesus monkey (Macaca mulatta) Adv Anat Embryol Cell Biol 68:1–84
Hayek H von (1931) Ein menschlicher Embryo mit 16 Urwirbeln, 25 Tage alt. Anat Anz 71:194–202
Hendrickx AG, Swayer RH (1975) Embryology of the rhesus monkey. In: Bourne GH (ed) The rhesus monkey, vol II Management, reproduction and pathology. Academic, New York, pp 141–169
Hinrichsen K (1985) The early development of morphology and patterns of the face in the human embryo. Adv Anat Embryol Cell Biol 98:1–79
Jacobson AG (1980) Computer modeling of morphogenesis. Am Zool 20:669–677
Johnston JB (1909) The morphology of the forebrain vesicle in vertebrates. J Comp Neurol 19:457–539
Keibel F (1889) Zur Entwickelungsgeschichte der Chorda bei Säugern (Meerschweinchen und Kaninchen). Arch Anat Physiol Anat Abt 329–388
Kirby ML, Bockman DE (1984) Neural crest and normal development: a new perspective. Anat Rec 209:1–6
Le Lièvre C (1984) Rôle des cellules mésectodermiques issues des crêtes neural céphaliques dans la formation des arcs branchiaux et du squelette viscéral. J Embryol Exp Morphol 31:453–477
Low A (1908) Description of a human embryo of 13–14 mesodermic somites. J Anat Physiol 42:237–251
Marin-Padilla M (1971) Early prenatal ontogenesis of the cerebral cortex (neocortex) of the cat (Felis domestica): A Golgi study. I. The primordial neocortical organization. Z Anat Entwickl-Gesch 134:117–145
Marin-Padilla M (1984) Neurons of layer I. A developmental analysis. In Peters and Jones, Cerebral Cortex, vol. 1 Ch. 14, Plenum Press, New York, pp 447–478
McBride RE, Moore GW, Hutchins GM (1981) Development of the interventricular septum in the normal human heart. Am J Anat 160:309–331
Mori T (1959) Histochemical studies on the distribution of alkaline phosphatase in early human embryos. II. Observations on an embryo with 13–14 somites. Arch Histol Jpn 18:197–209
Müller F, O'Rahilly R (1980) The early development of the nervous system in staged insectivore and primate embryos. J Comp Neurol 193:741–751
Müller F, O'Rahilly R (1983) The first appearance of the major divisions of the human brain at stage 9. Anat Embryol 168:419–432
Müller F, O'Rahilly R (1984) Cerebral dysraphia (future anencephaly) in a human twin embryo at stage 13. Teratology 30:167–177
Müller F, O'Rahilly R (1985) The first appearance of the neural tube and optic primordium in the human embryo at stage 10. Anat Embryol 172:157–169
Mulnard J (1955) Contribution à la connaissance des enzymes dans l'ontogénèse. Les phosphomonoestérases acide et alcaline dans le développement du rat et de la souris. Arch Biol 66:525–685
Nichols DH (1981) Neural crest formation in the head of the mouse embryo as observed using a new histological technique. J Embryol Exp Morphol 64:105–120
Nichois DH (1986) Formation and distribution of neural crest mesenchyme to the first pharnygeal arch region of the mouse embryo. Am J Anat 176:221–231
Noden DM (1975) An analysis of the migratory behavior of avian cephalic neural crest cells. Dev Biol 42:106–130
Noden DM (1978) The control of avian cephalic neural crest cytodifferentiation. I. Skeletal and connective tissues. II. Neural tissues. Dev Biol 67:296–312; 313–329
O'Rahilly R (1963) The early development of the otic vesicle in staged human embryos. J Embryol Exp Morphol 11:741–755
O'Rahilly R (1965) The optic, vestibulocochlear, and terminal-vomeronasal neural crest in staged human embryos. In: Rohen JW (ed) Second symposium on eye structure. Schattauer, Stuttgart, pp 557–564
O'Rahilly R (1966) The early development of the eye in staged human embryos. Contrib Embryol Carnegie Inst 38:1–42
O'Rahilly R (1973) Developmental stages in human embryos, including a survey of the Carnegie collection. Part A: Embryos of the first three weeks (Stages 1 to 9). Carnegie Institution of Washington, Washington DC
O'Rahilly R, Müller F (1981) The first appearance of the human nervous system at stage 8. Anat Embryol 163:1–13
O'Rahilly R, Müller F (1981) The origin of the ectodermal ring in staged human embryos of the first 5 weeks. Acta Anat 122:145–157
O'Rahilly R, Müller F (1986) The meninges in human development. J Neuropathol Exp Neurol 45:588–608
O'Rahilly R, Müller F, Hutchins GM, Moore GW (1984) Computer ranking of the sequence of appearance of 100 features of the brain and related structures in staged human embryos during the first 5 weeks of development. Am J Anat 171:243–257
Orts-Llorca F, Rodriguez AL, Monasterio AC (1958) Embrion humano de 14 pares de somitos. Cirugia Ginec Urol 12:226–232
Pacheco MA, Marks RW, Schoenwolf GC, Desmond ME (1986) Quantification of the initial phases of rapid brain enlargement in the chick embryo. Am J Anat 175:403–411
Politzer G (1928) Über einen menschlichen Embryo mit 18 Ursegmentpaaren. Z Anat Entwgesch 87:674–727
Putz B, Morriss-Kay G (1981) Abnormal neural fold development in trisomy 12 and trisomy 14 mouse embryos. J Embryol Exp Morphol 66:141–158
Schoenwolf GC (1978) Effects of complete tail bud extirpation on early development of the posterior region of the chick embryo. Anat Rec 192:289–295
Schoenwolf GC (1982) On the morphogenesis of the early rudiments of the developing central nervous system. Scann Electr Microsc 1:289–308
Schoenwolf GC, Desmond ME (1984a) Descriptive studies of occlusion and reopening of the spinal canal of the early chick embryo. Anat Rec 209:251–263
Schoenwolf GC, Desmond ME (1984b) Neural tube occlusion precedes rapid brain enlargement. J Exp Zool 230:405–407
Schoenwolf GC, Chandler NB, Smith JL (1985) Analysis of the origins and early fates of neural crest cells in caudal regions of avian embryos. Dev Biol 110:467–479
Sensenig EC (1951) The early development of the meninges of the spinal cord in human embryos. Contrib Embryol Carnegie Inst 34:145–157
Smart IHM (1965) The operation of ependymal ‘choke’ in neurogenesis. J Anat 99:941–943
Steiner K (1929) Über die Entwicklung und Differenzierungsweise der menschlichen Haut. I. Über die frühembryonale Entwicklung der menschlichen Haut. Z. Zellforsch mikrosk Anat 8:691–720
Sternberg H (1927) Beiträge zur Kenntnis des vorderen Neuroporus beim Menschen. Z Anat Entwicklungsgesch 82:747–780
Streeter GL (1942) Developmental horizons in human embryos. Description of age group XI, 13 to 20 somites, and age group XII, 21 to 29 somites. Contrib Embryol Carnegie Inst 30:211–245
Svajger A, Kostovic-Knezevic L, Bradamante Z, Wrischer M (1985) Tail gut formation in the rat embryo. Roux's Arch Dev Biol 194:429–432
Tam PPL (1984) The histogenetic capacity of tissues at the caudal end of the embryonic axis in the mouse. J Embryol Exp Morphol 82:253–266
Tan SS, Morris-Kay GM (1985) The development and distribution of the cranial neural crest in the rat embryo. Cell Tissue Res 240:403–416
Tuckett F, Morris-Kay GM (1985) The kinetic behaviour of the cranial neural epithelium during neurulation in the rat. J Embryol Exp Morphol 85:111–119
Tuckett F, Lim L, Morriss-Kay GM (1985) The ontogenesis of cranial neuromeres in the rat embryo. I. A scanning electron microscope and kinetic study. J Embryol Exp Morphol 87:215–228
Verwoerd CDA, van Oostrom CG (1979) Cephalic neural crest and placodes. Adv Anat Embryol Cell Biol 58:1–75
Wahlsten D (1981) Prenatal schedule of appearance of mouse brain commissures. Dev Brain Res 1:461–473
Wallin IE (1913) A human embryo of thirteen somites. Am J Anat 15:319–331
Watt JC (1915) Description of two young human embryos with 17–19 paired somites. Contrib Embryol Carnegie Inst 2:5–44
Wen IC (1928) The anatomy of human embryos with seventeen to twenty-three pairs of somites. J Comp Neurol 45:301–376
Author information
Authors and Affiliations
Additional information
Supported by research grant No. HD-16702, Institute of Child Health and Human Development, National Institutes of Health (USA)
Rights and permissions
About this article
Cite this article
Müller, F., O'Rahilly, R. The development of the human brain and the closure of the rostral neuropore at stage 11. Anat Embryol 175, 205–222 (1986). https://doi.org/10.1007/BF00389597
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00389597