Freiburger historische Bestände - digital

354

Cunningham Memoirs.

Fraser's work. The perspective view of the degree to which the opercula
cover the insula is in exact agreement with the foregoing description.

The localization of the individual sulci and gyri on the surface of the
insula is greatly assisted by Professor Cunningham's observations on p. 95
of this Memoir, and by the previous descriptions of Eberstaller (p. 96), the
sulcus centralis insulae from its first appearance in development (Cunningham
) lies in the line of the fissure of Rolando. Since it bounds posteriorly
the pole of the insula, all that is necessary to determine its situation is to
continue the line of the fissure of Rolando (for determination of this see
p. 323), down across the edge of the operculum, the Sylvian fissure, and
the superior temporal gyrus, passing over this obliquely as far as a point
which is horizontally opposite the external orbital sulcus.

The sulcus prsecentralis insulse, which, though at first in line with the
sulcus prsecentralis inferior of the outer surface of the hemisphere, moves
forwards at its upper end during development, so as to correspond with the
anterior limb of the Sylvian fissure. The postcentral sulcus of the insula
lies fairly in line with the intraparietal sulcus on the outer surface. It runs
forwards as well as downwards, and consequently follows a very similar
course to that of the central sulcus.

The external projection of these on the skull is therefore particularly
easy.

Putting aside for the present the conclusions on this point which may
properly be drawn from more recent research, the earlier observations of
Hefftler must be alluded to.

In Hefftler's drawing (fig. 1, loc. cit.), he represents the insula as
being covered by the anterior two-thirds of the superior temporal gyrus
in its whole breadth, the hinder fourth of the inferior half of the third
frontal gyrus, and narrow strips of the lower ends of the central gyri (not
reaching to the summits of Eberstaller's transverse sulci), and finally the
hindmost limit is placed opposite the lower end of the inferior postcentral
gyrus.

Hefftler figures the insula as lying (seen from the norma verticalis)
partly anteriorly, partly posteriorly, to the coronal fissure, in the respective
proportions of 1 to 2 U, e. one-third in front of the suture), the occipital