Freiburger historische Bestände - digital

350

Cunningham Memoirs.

roughly its situation between the latter-named point and the parietooccipital
fissure. If this distance be taken as 100, then the distance
from the parieto-occipital fissure to the marginal level of the calcarine,
and from thence to the occipital pole, is about as 75 to 25.

Since the evidence from experimental and clinical research coincides with
Professor Cunningham's morphological conclusions that it is the apex of the
cuneus lobule, or, in other words, the anterior portion (" stem," see p. 42)
of the calcarine fissure, it is important to note the depth of this from the
surface. This is easily ascertained, since a vertical line dropped through
the site of the parieto-occipital fissure passes also through the apex of the
cuneus. Almost the whole, therefore, of the mesial surface of the occipital
lobe above the level of the torcular Herophili consists of the cuneus. The
lingual lobule, lying as it does between the calcarine fissure and the collateral
sulcus, lies partly against the falx cerebri, e. g. immediately below
the calcarine fissure, but for the most part it is in contact with the
tentorium (yid. inferior surface of lobes).

The groove formed in the right hemisphere by the pressure of the
lateral sinus deviates the margin of the hemisphere to the right.

(D) Tempokal Lobe.—The exposure of the temporal lobe correctly
being a matter of much practical value, it is necessary first to mark the
situation of the fissure of Sylvius. The next point is the determination
of the lower limit of the surface of the lobe, which is just beneath the outer
part of the cranium. We have already seen that the margin of the
hemisphere corresponds with, in the majority of cases, the centre of the
zygomatic arch, or at least its upper border. It now remains to determine
what part of the hemisphere composes this, the lower border of the "free"
part of the temporal lobe. In every case it is the third temporal gyrus, and
it is the centre of the gyrus. Thus, there is for present consideration
on the outer surface of the lobe the following parts:—the superior temporal
sulcus, or parallel sulcus, the middle temporal sulcus, the superior, middle, and
upper half of the inferior temporal gyri, respectively.

(a) Sulcus Temporalis Superior vel Parallelis. — This sulcus commences
anteriorly usually exactly at the squamo-sphenoidal (pteral) suture; it then
runs backwards very parallel to the fissure of Sylvius, crossing, like the