Freiburger historische Bestände - digital

PLATE I.

[A series of Views of the Cerebrum of the Human Foetus at different stages of development. The various figures were

drawn upon the stone from photographs.]

LETTEEING COMMON TO ALL THE FIGURES.

f-1 . •

Sulcus frontalis primus.

p. .

. Intraparietal sulcus.

f° . ■

Sulcus frontalis secundus.

P-1 ■

Sulcus postcentralis inferior.

/. m.

Sulcus frontalis medius.

P-2 -

Sulcus postcentralis superior.

p. c. .

Earlj- sulcus praecentralis inferior.

p.3

Ramus horizontalis of the intraparietal sulcus.

p c. i.

. Sulcus praecentralis inferior.

p.* ■

Ramus occipitalis of the intraparietal sulcus.

p. c.

Sulcus praecentralis superior.

e. p. .

Fissura perpendicularis externa.

r. . .

. Fissure of Rolando.

e. e. .

. External calcarine fissure.

rJ .

. Lower piece of the fissure of Rolando.

/. a. ,

. Fissura arcuata.

r.2 .

. Upper piece of the fissure of Rolando.





[N.B.—In Figures 11, 14, and 24 the dotted outlines indicate in each case the area of cerebral surface covered by the

parietal bone.]

Figure 1.—Outer surface of the cerebrum of a foetus which had probably reached the tenth or eleventh week of development
. (Specimen in the Museum of University College, London.)

Figures 2 and 3.—Two different views of the cerebrum of a foetus which had apparently reached a stage of development
corresponding to the eleventh week. (Specimen in the Museum of University College, London.) In Figure 3 a curious
projection from the hinder end of the right hemisphere («) is seen. (Vide p. 25 of the text.)

Figures 4 and 5.—The two hemispheres of the cerebrum of a foetus in the twelfth week of development:—p. o. precursor
of the parieto-occipital fissure ; c. precursor of the calcarine fissure.

Figures 6, 7 and 8.—Different views of the cerebrum of a foetus preserved in the Museum of University College,
London; period of development, twelfth week:—b., transitory fissure in the ground of the future Sylvian fissure.

Figures 9 and 10.—Different views of a foetal cerebrum preserved in the Biological Museum of the University of Oxford.
Period of development, twelfth week. The figures were drawn on the stone from photographs supplied by Professor Victor
Horsley. The cerebrum in each case is represented somewhat larger than it is in reality.

Figures 11 and 12.—The external and mesial surfaces of the left hemisphere of a foetal cerebrum in the early part of
the fourth month of development—say, the thirteenth week :—/., transitory fissure ; e., anterior part of the fissura arcuata ;
f.a., fissura arcuata; d., radial transitory fissure; p. o., precursor of the parieto-occipital fissure; e. c, external calcarine
fissure ; c, precursor of the calcarine fissure; h., hippocampal fissure.

Figure 13.—The opposite hemisphere to that represented in Figures 11 and 12, with the roof of the cerebral cavity
removed:—/., infolding produced by the fissure marked /. in Figure li ; /. a., infolding corresponding to the main part of
the fissura arcuata; c. corpus striatum.

Figures 14 and 15.—Outer and mesial surfaces of a left fcetal hemisphere in the early part of the fifth month of

development:—c, calcarine fissure.

Figure 16.—Mesial face of a light foetal hemisphere (same brain as Figures 14 and 15) in the early part of the fifth
month of development:—p. o., parieto-occipital fissure; c, calcarine fissure.

Figure 17.—Outer surface of a left cerebral hemisphere (considerably enlarged) in the early part of the fifth month of
development. The specimen is preserved in the Biological Museum of the Oxford University. Photograph obtained from
Professor Victor Horsley.

Figure 18.—The occipital extremities of two hemispheres of a brain in the early part of the fifth month of development
removed by a coronal section. The portions removed are viewed from the front. The cavity of the posterior ventricular
horn is seen, aud also the intraventricular projections into it, caused by the external calcarine (e. c.) and calcarine (<?.) fissures

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