Книги по МРТ КТ на английском языке / The Embryonic Human Brain An Atlas of Developmental Stages. Third Edition. 2006. By Ronan O'Rahilly

Choroid

fissure

Commissure

of fornix

Indusium griseum & hippocampus

Corpus callosum

Fornix

Stria terminalis

Thalamus

Ant. commissure

Figure 26–3. A comparison of the medial surface of the forebrain at (A) 80, (B) 95, (C) 150, and (D) approximately 265 mm. The left thalamus has been sectioned sagittally (shaded by horizontal lines). In A, B, and C the entire brain stem has been removed, whereas in D it has been sectioned transversely at the level of the midbrain and its caudal portion has been eliminated. The considerable increase in length of the corpus callosum (shown in yellow) after 100 mm can readily be appreciated by comparing B and C. In D the corpus callosum shows clearly the rostrum, genu, central part, and splenium. The commissural plate beneath the corpus callosum becomes attenuated (C) to form the septum pellucidum. Modified from models in Keibel and Mall (1912).

The upper right-hand drawings show schematically the arrangement of the pia mater over the corpus callosum at 100 mm, 170 mm, and at birth. As the corpus callosum grows posteriorly, a pial layer (b) is reflected backwards over the original layer (a), so that a double fold is formed. This is the velum interpositum, between the two layers of which blood vessels can pass forward beneath the corpus callosum, through the transverse fissure (asterisk). These vessels contribute to the tela choroidea of the third ventricle.

See Figure 23 – 29

Somatic afferent

Visceral afferent

Visceral efferent

Somatic efferent

Inferior cerebellar peduncle

Figure 26–5. Dorsal views of the rhombencephalon (A) at 8 postfertilizational weeks (stage 23: cf. Figs. 23–29 and 23–30) and (B, C) in two different reconstructions from the newborn. The arrangement of the nuclei and tracts, as well as the location of the rhombencephalic nuclei at 8 weeks, are very similar to those in the newborn. The striking resemblance between the rhombencephalon of the newborn and that of the embryo at 8 weeks is based on the circumstance that the fundamental organization of the rhombencephalon is attained much earlier than that of other parts of the brain. Figure 26–5B is based on a reconstruction by Sabin (1901). Figure 26–5C is after Hikji (1933). The neurons in the nucleus of the tractus solitarius are still immature at birth (Denawit-Saubie´ et al., 1994).

Figure 26–10. (A) and (B) The arterial system of the newborn. The vessels

A marked are the three cerebral arteries (A.C., M.C., P.C.), the posterior communicating (P. co.), the anterior choroidal (A. chor.), the superior cerebellar (Sup. cbl), and the anterior and posterior inferior cerebellar arteries (AICA, PICA). The asterisk indicates the hypophysis. The posterior communicating is relatively large prenatally and in the newborn. In the adult, however, the blood flow in the posterior cerebral (initially merely a collateral branch of the posterior communicating) has been transferred from the carotid to the basilar system. These drawings are based on graphic reconstructions made by Padget (1948), whose work should be studied for further details. The venous system has been illustrated by Padget (1957, Fig. 17).

B

Anterior & middle cerebral

Internal carotid

Posterior communicating

Posterior cerebral

Basilar

Vertebral

C D

Figure 26–11. Examples of images during trimester 2. (A) and (B) Horizontal sections at 23 postmenstrual weeks. (C) and (D) Views of the maternal pelvis showing the fetal brain at 26 postmenstrual weeks. All four views present some pathological features. Courtesy of Robert Harris, M.D., Dartmouth Hitchcock Medical Center, Hanover, NH.

a See also Table 17–3 for development of dopaminergic neurons.

b Neocortical formation using immunohistochemistry for reelin, calretinin and glutamic acid decarboxylase.

Figure 26–12. Graph showing fresh brain weight plotted against estimated weeks after fertilization. This is a Gompertz prediction with a 95% confidence band. After McLennan, Gilles, and Neff in Gilles, Leviton, and Dooling (1983).

Figure 26–13. The diameter of the fixed fetal brain (n = 156) modified from Dunn (1921). The measurements are from the frontal to the occipital pole, and from the right to the left temporal pole.