Neuroanatomy Draw It To Know It

280 Neuroanatomy: Draw It to Know It

The Insula ( Advanced )

Here, we will draw the insula (aka the island of Reil),
which underlies the cerebral opercula. First, draw a lat-
eral hemisphere. Th en, carve out the center of the hemi-
sphere and indicate that the circular sulcus circumscribes
the insula (except in the antero-inferior region at the
limen insulae — the insular apex). Next, show that the
central sulcus extends through the insula and divides it
into anterior and posterior lobules. Th en, indicate that
the anterior lobule contains three short insular g yri and
that the posterior lobule contains two long insular g yri.
Within the anterior lobule, draw the precentral
sulcus, and anterior to it, draw the short insular sulcus.
In between the precentral and central sulci, label the
posterior short insular g yrus; in between the precentral
and short insular sulci, label the middle short insular
g yrus; and fi nally, anterior to the short insular sulcus,
label the anterior short insular g yrus.
Now, within the posterior lobule, draw the postcen-
tral sulcus, and in between it and the central sulcus, label
the anterior long insular g yrus, and posterior to it, label
the posterior long insular g yrus.

Next, draw a coronal view of the insula so we can, at

least partially, draw its diff erent opercular coverings. In

accordance with Nieuwenhuys' description, label the

orbital operculum, which lies inferior to the anterior

horizontal ramus of the Sylvian fi ssure; next, label the

frontal operculum, which lies in between the anterior

horizontal and anterior ascending Sylvian fi ssure rami;

then, label the parietal operculum, which lies in between

the anterior ascending and posterior Sylvian fi ssure rami;

and fi nally, label the temporal operculum, which lies

inferior to the posterior ramus of the Sylvian fi ssure.

Indicate that the temporal operculum is formed from

both the superior temporal g yrus and transverse tempo-

ral g yri (Heschl’s g yri).

Th e insula has widespread intracortical connectivity,

including connections to the hypothalamus, thalamus,

cortical sensory association areas, auditory cortex, and

limbic system. It has been shown to play a role in pain

modulation, appetite, awareness of visceral sensation,

anxiety and emotion, socialization, auditory processing ,

and much more.^4 – 6 , 9 , 12 – 14

1 Central sulcus

2 Lateral sulcus, posterior branch

3 Lateral sulcus, ascending branch

4 Frontoparietal operculum

5 Circular sulcus of the insula

6 Lateral sulcus, anterior branch

7 Long gyrus of the insula

8 Central sulcus of the insula

9 Short gyri of the insula

10 Frontal operculum

11 Temporal operculum

12 Limen insulae

13 Anterior pole of the insula

FIGURE 16-4 Insular cortex. Used with permission from Nieuwenhuys, Rudolf, Christiaan Huijzen, Jan Voogd, and SpringerLink (Online service).
“Th e Human Central Nervous System.” Berlin, Heidelberg: Springer Berlin Heidelberg, 2008.