276 Neuroanatomy: Draw It to Know It
Cerebral Hemisphere — Medial Face
Here, we will draw the lobes, g yri, and sulci of the medial
face of the cerebrum. Draw an outline of the medial face
of a cerebral hemisphere. Label the cingulate sulcus
above and in parallel to the corpus callosum. Th en, label
the collateral sulcus in the temporal region in parallel to
the brain’s inferior border. Indicate that these sulci delin-
eate the limbic lobe. Next, draw the central sulcus, and
anterior to it, label the frontal lobe. Now, draw the pari-
eto-occipital sulcus, and show that it separates the pari-
etal lobe, anteriorly, from the occipital lobe, posteriorly.
Next, use the subparietal sulcus to demarcate the bound-
ary between the parietal and limbic lobes. Now, to sepa-
rate the temporal and occipital lobes, dot a line between
the pre-occipital notch and the parieto-occipital sulcus,
and label the line as the basal parietotemporal line. Th e
temporal lobe lies anterior to this line. Note that the
basal parietotemporal line is alternatively drawn from
the pre-occipital notch to the anterior end of the ante-
rior calcarine sulcus (drawn later).
Now, let’s draw the g yri and sulci of the medial sur-
face of the cerebral hemisphere. First, redraw the hemi-
sphere — include the corpus callosum and thalamus.
Along the outer contour of the corpus callosum, label
the callosal sulcus, and in parallel to it, draw the cingu-
late sulcus. In between these sulci, label the cingulate
gyrus.
Next, in the central, superior hemisphere, draw the
central sulcus, and anterior to it, draw the paracentral
sulcus. Between these two sulci, draw the anterior para-
central g yrus — the medial extension of the precentral
g yrus. Anterior to the paracentral sulcus label the supe-
rior frontal g yrus (aka the medial frontal g yrus). Th en,
posterior to the central sulcus, continue the cingulate
sulcus as the pars marginalis (the marginal branch of the
cingulate sulcus), and between it and the central sulcus,
label the posterior paracentral g yrus — the medial exten-
sion of the postcentral g yrus. Note that together the
anterior and posterior paracentral g yri are referred to as
the paracentral lobule.
Now, posterior to the pars marginalis, draw the pari-
eto-occipital sulcus, and in between these two sulci, label
the precuneus g yrus. Th en, show that the subparietal
sulcus separates the precuneus from the cingulate g yrus.
Next, show that the calcarine sulcus extends directly pos-
terior from the inferior tip of the parieto-occipital sulcus,
and then indicate that the anterior calcarine sulcus
extends anteriorly from the inferior tip of the parieto-
occipital sulcus to underneath the posterior corpus cal-
losum (the splenium). Within the occipital lobe, superior
to the calcarine sulcus, label the cuneus, and inferior to
it, label the lingual g yrus. Now, along the path of the
anterior calcarine sulcus, draw the collateral sulcus, and
superior to it, label the parahippocampal g yrus. Th en,
inferior and in parallel to the collateral sulcus, label the
occipitotemporal sulcus, and in between these two sulci,
label the fusiform g yrus. Finally, inferolateral to the fusi-
form g yrus, label the inferior temporal g yrus.
Note that there are substantial variations in the defi -
nitions of the anatomy of the inferomedial temporal and
occipital g yri and substantially diff ering semantics used
to describe these areas. For instance, the lingual g yrus is
sometimes referred to as the medial occipitotemporal
g yrus and the fusiform g yrus is sometimes referred to as
the lateral occipitotemporal g yrus. Th e fusiform g yrus is
also sometimes referred to as the combined medial and
lateral occipitotemporal g yri or as a subportion of the
occipitotemporal g yrus. Also, the collateral sulcus is
alternatively referred to as the medial occipitotemporal
sulcus and the occipitotemporal sulcus is sometimes
called the lateral occipitotemporal sulcus.^1 – 6