Freiburger historische Bestände - digital

CHAPTER V.

THE PRiECENTRAL AND OTHER SULCI ON THE EXTERNAL SURFACE OF THE

FRONTAL LOBE.





page

I.

General Statement,

. 244

II.

Sulcus Pjeuecentralis Inferior, .

. 247

III.

Sulcus Pr^ecentralis Superior, .

. 256

IV. Sulcus Prjecentralis Medius,

. 258

V.

Sulcus Frontalis Secundus,

. 260

VI.

Sulcus Frontalis Primus,

. 263

VII.

The Sulcus Frontalis Medius, .

. 264

VIII.

Sulcus Frontalis Mesialis, .

. 268

PAGE

IX. Development op the Frontal Sulci, . 270
X. Frontal Furrows in the .Apes, . . 279
XI. Exposed Part of the Insula and the
Sulcus Fronto-Orbitalis in the
Apes, . . . . . .296

XII. Topography of the Inferior Prje-

central Sulcus, .... 300

XIII. Summary,......302

I. General Statement.—Pansch compared the prsecentral sulcus (his
first " Primarfurche ") with the intraparietal sulcus (his third " Primarfurche
), and stated that they are formed on a " completely similar, and
almost symmetrical" plan.* Certainly, the correspondence in the disposition
of the several parts of these two furrows is very marked, although this
correspondence does not lie altogether in the lines laid down by Pansch.
The prsecentral sulcus presents a vertical part which limits the anterior
cerebral convolution in front; the intraparietal sulcus possesses a vertical
portion which bounds the posterior central convolution behind. Each of
these vertical portions, together with the fissure of Rolando (the second
Primarfurche), which lies between them, is composed of two developmentally
distinct pieces. In the case of the intraparietal sulcus these are termed
the sulcus postcentralis inferior, and the sulcus postcentralis superior, and

* " Ueber die typische Anordnung der Furchen und Wmdungen," &c, &c. Archiv fur
Anthropologic; Dritter Band; p. 235. 1869.