Freiburger historische Bestände - digital

344

Cunningham Memoirs.

anterior vertical limb of the fissure of Sylvius, inasmuch as it lies between
the latter and the inferior prsecentral furrow. The anterior vertical limb
we have seen before to be comparatively inconstant in its relation to the
cranial vault, but on the whole to frequently arise behind the coronal
suture, and to pass upwards and forwards, soon cutting the former line,
and coinciding with it or passing in front of it. The sulcus diagonalis
extends between the angle formed by the union or proximity of the inferior
prsecentral and inferior frontal sulci, and the line of the anterior ascending
limit of the fissure of Sylvius ; for this reason it most frequently lies just
behind the coronal suture.

Sulcus Fronto-Marginalis.—This furrow, of some import morphologically,
is nevertheless at present without much interest, inasmuch as the function
of the region of cortex it divides is as yet unascertained. First observed
by Wernicke, this sulcus is now well recognized as the termination of the
sulcus frontalis medius. It is transverse in direction, and lies immediately
above the orbital margin of the frontal lobe, running inwards and outwards.
On the inner side it reaches nearly to the margin of the longitudinal
fissure, but on the outer side it either stops short or its place is taken by a
subordinate sulcus or sulci. This sulcus subdivides the anterior extremity
of the middle frontal gyrus and the outer and angular border of the convex
surface of the frontal lobe, and consequently lies close beneath the supraorbital
line of Broca, which gives the minimal frontal diameter, and, as he
stated, marks the place of separation of the cranium and face.

Sulcus Transversus Inferior.—Eberstaller has so termed a small subordinate
sulcus, which, in 1887, Semon and myself noted to be a very important
landmark of representation of function * in the brain of the lower apes
[Macacus sinicus and M. rhesus). It sub-divides vertically the foot of the
ascending frontal gyrus.

During an examination of probably more than 300 hemispheres of
Macacus, I have never seen it absent. While, however, of this evidently
high phylogenetic importance, its relations to the gyrus alter in

* It separates the chief representation of adduction of the vocal cords from the representation
of the higher and outer facial movements, and further (Beevor and myself) the separation
of the pharyngeal movements from those of the jaw.