Cerebral Gyri & Sulci

• Draw the lateral aspect of the cerebrum.

• The superior/anterior portion is the frontal lobe.
• The superior/posterior portion is the parietal lobe.
• The inferior portion is the temporal lobe.
• The posterior portion is the occipital lobe.

• Next, draw the medial aspect the cerebrum.
• As reference points, include the corpus callosum, thalamus, and hypothalamus.

• The superior/anterior portion is the frontal lobe.
• The superior/posterior portion is the parietal lobe.
• The central portion as the limbic lobe.
• The inferior portion is the temporal lobe.
• The posterior portion is the occipital lobe.

Now, draw the inferior surface of the brain twice. As reference points, include the optic chiasm, pituitary stalk, mamillary bodies, and midbrain. Shade the lobes of the brain as follows: The anterior portion as the frontal lobe. The lateral middle region as the temporal lobe. The medial middle region as the limbic lobe. The posterior region as the occipital lobe.

• In the lower right hand corner, we display the abbreviations for the sulci.

Brain Atlas: Lateral Hemisphere Sylvian Fissure & Central Sulcus

• First, In the lateral hemisphere, label the Sylvian fissure (aka the lateral sulcus).
• Next, draw the central sulcus from the top of the brain to the Sylvian fissure.

Frontal Lobe

• Then, divide the anterior frontal lobe into three horizontally distributed gyri using two parallel sulci.
• Indicate that the top sulcus is the superior frontal sulcus and the bottom sulcus is the inferior frontal sulcus.
• Show that the superior frontal gyrus lies above the superior frontal sulcus.
• The middle frontal gyrus lies in between the superior and inferior frontal sulci
• The inferior frontal gyrus lies below the inferior frontal sulcus.
• Show that the inferior frontal gyrus comprises (from anterior to posterior) pars orbitalis, pars triangularis, and pars opercularis divisions.

Temporal Lobe

• Now, draw the superior temporal sulcus.
• Then, the inferior temporal sulcus.
• Show that the superior temporal gyrus lies above the superior temporal sulcus.
• The middle temporal gyrus lies in between the superior and middle temporal sulci.
• The inferior temporal gyrus lies below the inferior temporal sulcus.

Occipital Lobe

• Draw the superior occipital sulcus (aka the intraoccipital sulcus): it follows the path of the intraparietal sulcus.
• Draw the inferior occipital sulcus: it follows the path of the inferior temporal sulcus.
• Above the superior occipital sulcus, label the superior occipital gyrus.
• In between the two sulci, label the middle occipital gyrus (aka the lateral occipital gyrus).
• Below the inferior occipital sulcus, label the inferior occipital gyrus.
• The middle occipital gyrus is the largest of the occipital gyri on the lateral surface of the brain and it is sometimes subdivided into superior and inferior gyri.

Orbitofrontal Cortex

• Next, label the basal, anterior surface of the frontal lobe as the orbitofrontal cortex.

See: Orbital Gyri & Gyrus Rectus Precentral & Postcentral Gyri

• Now, anterior to the central sulcus, draw the precentral sulcus.
• Behind it, label the precentral gyrus, which is the primary motor area.
• Next, draw the postcentral sulcus.
• Anterior to it, label the postcentral gyrus, which is the primary sensory area.

Parietal Lobe

• Next, draw the intraparietal sulcus.

• Superior parietal lobule, superiorly.
• Inferior parietal lobule, inferiorly.

• Supramarginal gyrus, which caps the posterior end of the Sylvian fissure.
• Angular gyrus, which caps the posterior end of the superior temporal sulcus.

Brain Atlas: Medial Hemisphere Cingulate Gyrus

• Now, in the medial hemisphere, along the superior outside of the limbic lobe, draw the cingulate sulcus.
• And along the outer contour of the corpus callosum, label the callosal sulcus.
• In between the two, label the cingulate gyrus.

Central Sulcus

• Next, show that the central sulcus divides the frontal and parietal lobes.

Occipital Lobe

• Now, draw the calcarine sulcus at the posterior end of the occipital lobe.
• Superior to the calcarine sulcus, label the cuneus, and inferior to it, label the lingual gyrus.

Temporal Lobe

• Next draw the collateral sulcus in the superior temporal lobe.
• Above it, label the parahippocampal gyrus.
• Inferior to it, draw the occipitotemporal sulcus.
• In between the collateral and occipitotemporal sulci, label the fusiform gyrus.
• Finally, inferolateral to the fusiform gyrus, label the inferior temporal gyrus.
• Note that there are substantial variations in the definitions of the anatomy of the inferomedial temporal and occipital gyri and substantially differing semantics used to describe these areas. For instance, the lingual gyrus is sometimes referred to as the medial occipitotemporal gyrus and the fusiform gyrus is sometimes referred to as the lateral occipitotemporal gyrus. The fusiform gyrus is also sometimes referred to as the combined medial and lateral occipitotemporal gyri or as a subportion of the occipitotemporal gyrus. Also, the collateral sulcus is alternatively referred to as the medial occipitotemporal sulcus and the occipitotemporal sulcus is sometimes called the lateral occipitotemporal sulcus.

Paracentral Gyri

• Now, anterior to the central sulcus, draw the paracentral sulcus.
• Between these two sulci, label the anterior paracentral gyrus (which is the medial extension of the precentral gyrus).
• Anterior to the paracentral sulcus, label the superior frontal gyrus (aka the medial frontal gyrus).
• Then, posterior to the central sulcus, continue the cingulate sulcus as pars marginalis (the marginal branch of the cingulate sulcus).
• Between it and the central sulcus, label the posterior paracentral gyrus (which is the medial extension of the postcentral gyrus).
• Note that together the anterior and posterior paracentral gyri are referred to as the paracentral lobule.

Parieto-Occipital Region

• Now, posterior to pars marginalis, draw the parieto-occipital sulcus.
• In between these two sulci, label the precuneus gyrus.
• Next, indicate that the anterior calcarine sulcus extends anteriorly from the inferior tip of the parietooccipital sulcus to underneath the posterior corpus callosum (the splenium).
• Then, show that the subparietal sulcus separates the precuneus from the cingulate gyrus.

Brain Atlas: Inferior Surface

• Now, within the inferior surface of the brain, within the medial frontal lobe, label the olfactory sulcus.
• Medial to it, label the gyrus rectus.
• Lateral to it, label the orbital gyri and orbital sulci.
• Next, on the medial aspect of the occipital lobe, label the lingual gyrus.
• Now, within the temporal lobe, draw the collateral sulcus.
• Then, draw the occipitotemporal sulcus.
• Medial to the collateral sulcus, label the parahippocampal gyrus.
• In between the collateral and occipitotemporal sulci, label the fusiform gyrus.
• Next, lateral to the fusiform gyrus, label the inferior temporal gyrus.
• Now, at the anterior end of the collateral sulcus, label the rhinal sulcus; the collateral sulcus either merges with this sulcus or runs in parallel to it (see Drawing 21-3).
• Medial to it, the parahippocampal gyrus doubles back onto itself as the uncus; this is, generally, the first portion of the brain to herniate over the tentorium cerebellum during uncal herniation.

• Label the frontal pole at the anterior end of the frontal lobe.
• The temporal pole at the anterior end of the temporal lobe.
• The occipital pole at the posterior end of the occipital lobe.

• As shown, the area anterior to the central sulcus comprises the frontal lobe.
• Label the preoccipital notch along the posterior undersurface of the brain and then the parieto-occipital sulcus along the superior convexity of the brain.
• Note that the parietooccipital sulcus terminates abruptly in the superolateral convexity. On the contrary, the parieto-occipital sulcus is prominent on the medial surface of the brain.
• Now, dot a vertical line from the termination of the parietooccipital sulcus to the pre-occipital notch and label it as the lateral parietotemporal line.
• The occipital lobe lies posterior to this imaginary line.
• Next, dot a roughly horizontal line from the posterior end of the Sylvian fissure to the middle of the anterior border of the occipital lobe and label this line as the temporo-occipital line.
• The parietal lobe lies superior to this line.
• And the temporal lobe lies inferior to it.

• Hash a connection between the cingulate sulcus, subparietal sulcus, and collateral sulcus; as shown, these sulci delineate the limbic lobe.
• As well, as shown, the area anterior to the central sulcus is the frontal lobe.
• Also, as shown, the parieto-occipital sulcus separates the parietal lobe, anteriorly, from the occipital lobe, posteriorly.
• Label the preoccipital notch along the posterior undersurface of the brain.
• Dot a line between the pre-occipital notch and the parieto-occipital sulcus, and label the line as the basal parietotemporal line.
• The temporal lobe lies anterior to this line and the occipital lobe lies posterior to it.
• Note that the basal parietotemporal line is alternatively drawn from the pre-occipital notch to the anterior end of the anterior calcarine sulcus.
• Lastly, along the inferior surface of the brain, in the posterior one third of the hemisphere, draw the basal parietotemporal line.
• As shown, anterior to it is the temporal lobe, posterior to it, is the occipital lobe.
• Finally, note that the limbic lobe lies medial to the collateral sulcus.