Freiburger historische Bestände - digital

96

Cunningham Memoirs.

in order that I may be able to render intelligible the few additions to his
description which I wish to make, as well as the facts relating to the
development of the convolutions and sulci of the insula, which I have
observed. According to Eberstaller the anterior insula is connected entirely
with the frontal lobe, whilst the posterior insula is exclusively connected
with the parietal and temporal lobes.

The anterior insula presents three gyri which unite below to form the
pole of the island of Reil, whilst above they are separated from each other
by two sulci. These three convolutions Eberstaller names from before
backwards, the gyrus brevis primus, the gyrus brevis secundus, and the
gyrus brevis tertius (fig. 27). The gyrus primus and the gyrus tertius are,
as a rule, strongly marked, whilst the intermediate one is more weakly
developed. It appears to me that a better name for the gyrus tertius
would be the gyrus centralis anterior, seeing that this term would indicate
its position with reference to the central sulcus, and at the same time show
its relation to the anterior central (or ascending frontal) convolution on the
outer face of the hemisphere. The gyrus tertius is continued downwards
on the surface of the island of Eeil, very much in the direction of the
ascending frontal convolution, and its upper end lies concealed under that
part of the fronto-parietal operculum which is formed by this convolution
of the frontal lobe. Of the two sulci which separate the three gyri breves,
the anterior, termed by Eberstaller the sulcus anterior, is always well
expressed, but it rarely reaches so low as the pole of the anterior insula.
For reasons which will become more apparent afterwards, the term sulcus
prsecentralis Reillii, proposed by Guldberg would be more appropriate for
this sulcus. As a rule the second sulcus is merely a shallow depression of a
triangular form which intervenes between the upper portions of the gyrus
secundus, and the gyrus tertius.

But Eberstaller describes two additional gyri in connexion with the
anterior insula. These he terms the gyrus transversus and gyrus accesso-
rius. The gyrus transversus extends forwards from the pole of the island,
and is of the nature of an annectant gyrus, seeing that it connects the lower
part of the insula anterior with the under, or orbital face of the frontal
lobe. When superficial, as, indeed, it very frequently is, it is interposed