3. Medial Surface
• The main sulci and gyri on the medial surface of
the cerebral hemisphere are:
• Cingulate sulcus:
It is a curved sulcus that begins below the rostrum
of corpus callosum, then it passes in front of the
genu, then above and parallel to the body of
corpus callosum. It ends by curving upwards
towards the superiomedial border behind the
central sulcus to forms the anterior boundary of
the paracentral lobule.
4. Sulci of medial surface
Corpus callosum
Callosal sulcus
Cingulate sulcus
Central sulcus Suprasplenial sulcus
Parietooccipital sulcus
Calcarine sulcus
6. • Callosal sulcus:
Just above the corpus callosum.
• Cingulate gyrus:
It lies between the corpus callosum and the
cingulate sulcus.
The cingulate gyrus is responsible for variations
in pulse, blood pressure and respirations as
well as visceral and emotional activities i.e.
limbic association cortex.
8. • Medial frontal gyrus:
It is a part of the frontal lobe of the brain that lies in
front of the ascending ramus of cingulate sulcus.
Functionally, it is considered as part of the
prefrontal area. i.e. responsible for behavior,
attention and concentration.
• Paracentral lobule:
It is a part of the medial surface of the cerebral
hemisphere that lies in front of the terminal part
of the cingulate sulcus. This area receives the
terminal part of the central sulcus, thus it
contains part of precentral and postcentral gyri.
This area is responsible for motor and sensory
functions of the foot and perineum.
9. • Calcarine sulcus:
• It begins anteriorly below the splenium of
corpus callosum and it extends posteriorly to
the occipital pole where it curves slightly on
the superiolateral surface. It is joined by the
parieto-occipital sulcus that divides it into
precalcarine and postcalcarine sulci. The gyrus
that lies below the calcarine sulcus is termed
lingual gyrus.
10. • Parieto-occipital sulcus:
It is a vertical sulcus that cuts the superiomedial
border of the cerebral hemisphere about 5 cm in
front of the occipital pole. It extends slightly on
the superiolateral surface. On the medial surface
it reaches the calcarine sulcus, where both sulci
form a Y-shaped arrangement. The triangular
area between the two limbs of this –Y- is termed
cuneus. The area in front of the cuneus is termed
precuneus.
11. • Cuneus:
It is a triangular area lying between the post
calcarine and the parieto-occipital sulci. Its
function is visual.
• Pre cuneus:
This area lies between the terminal part of the
cingulate sulcus and the parieto – occipital
sulcus.
13. Sulci of inferior surface
Orbital part
Tentorial part part
Olfactory sulcus
H shaped orbital sulcus
Rhinal sulcus
Collateral sulcus
Occipitotemporal sulcus
14. Inferior Surface
is divided by the stem of lateral sulcus into an
orbital part and a tentorial part.
A. The orbital part presents the following sulci and
gyri.
1. Olfactory sulcus: It is a straight sulcus that forms
the lateral boundary of a longitudinal gyrus
termed gyrus rectus.
2. H-shaped orbital sulcus: That divides the lateral
part of this area into anterior, posterior, medial
and lateral orbital gyri.
15. B. The tentorial surface presents the
following sulci and gyri.
• Rhinal sulcus: It is a small sulcus that lies in the
anterior part of this surface near the temporal
pole. It forms the lateral boundary of the uncus.
• Collateral sulcus: It appears as a continuation of
the rhinal sulcus and it extends posteriorly to end
slightly short of the occipital pole. Its anterior
part forms the lateral boundary of the
parahippocampal gyrus. Its posterior part is
separated from the calcarine sulcus by the lingual
gyrus.
16. • Uncus: It lies in the most anterior part of the tentorial
surface where it is bounded laterally by the rhinal
sulcus.
• Parahippocampal gyrus: It appears as a continuation of
the uncus and it terminates at the level of the splenium
of corpus callosum where it receives the isthmus. It is
bounded laterally by the collateral sulcus.
• Lingual gyrus: It appears as a continuation of the
parahippocampal gyrus where it is bounded laterally by
the collateral sulcus and medially by the calcarine
sulcus. It begins behind the level of the splenium of
corpus callosum
17. • .
• Occipitotemporal sulcus: it runs lateral and
parallel to the collateral sulcus.
• Medial occipitotemporal gyrus: lies medial to
the occipitotemporal sulcus.
• Lateral occipitotemporal gyrus: lies lateral to
the occipitotemporal sulcus.
