1. Brain Anatomy
Sulci & Gyri
By
Dr.Sajith

2. • Sulcus : A sulcus is depression or fissure
in the surface of the brain. ( valleys )
• Gyrus : A gyrus is a ridge on the cerebral
cortex. It is generally surrounded by one
or more sulci ( hills )

3. Typical continous fissure
Interhemispheric fissure
Sylvian fissure ( lateral sulcus )
Parieto-occipital fissure
Collateral sulcus
Central sulcus
Calcarine Sulcus

4. Interhemispheric fissure
Deep sulcus upto
corpus collosum
Divides brain into
two hemisphere

5. Sylvian fissure
deep, mostly
horizontal
insula is buried
within it
separates temporal
lobe from parietal
and frontal lobes

6. Parieto - occipital fissure
very deep
often Y-shaped
from sagittal view
X-shaped in
horizontal and
coronal views

7. Collateral sulcus
Divides lingual
and
parahippocampal
gyri from fusiform
gyrus.

8. Central sulcus
usually
freestanding (no
intersections)
Seperates frontal
and parietal lobe.

9. Calcarine sulcus

10. Lobes of brain
Frontal lobe.
Parietal lobe.
Temporal lobe.
Occipital lobe.
Limbic lobe.
Insular lobe.

11. • Frontal lobe:
Anterior region of hemisphere; anterior to
central sulcus, superior to sylvian fissure
• Parietal lobe:
Posterior region of hemisphere; posterior to
central sulcus, anterior to parietooccipital
sulcus
• Occipital lobe:
Posterior to parietooccipital sulcus
• Temporal lobe:
Inferior to sylvian fissure, anterior to
angular gyrus

13. Lateral surface of brain

14. Medial surface of brain

15. Basal surface of brain

16. frontal lobe
The frontal lobe constitutes the entire region
in front of the central sulcus. Immediately
in front of the central sulcus lies the
precentral gyrus, which is the primary
motor region of the cerebral cortex. In
front of the precentral gyrus, the rest of
the frontal lobe is divided
into superior, middle and inferior frontal
gyri.

17. Frontal lobe
Sulci:
 Superior frontal sulcus.
 Inferior frontal sulcus.
 Precentral sulcus.
Gyri:
 Superior frontal gyrus.
 Middle frontal gyrus.
 Inferior frontal gyrus.
 Precentral gyrus

18. Frontal lobe gyrus
Lateral Surface

Precentral Gyrus --- primary motor area

Superior Frontal Gyrus

Middle Frontal Gyrus

Inferior Frontal Gyrus

Pars Opercularis

Pars Triangularis

Pars Orbitalis
Medial Surface

Medial Frontal Gyrus

Paracentral Lobule
Basal Surface

Rectus Gyrus

Orbital Gyrus ( superior, medial ,lateral ,inferior )

23. Parietal lobe
Behind the central sulcus, and above the
lateral fissure, lies the parietal lobe. Its
most anterior part is the postcentral
gyrus, which is the site of the primary
somatosensory cortex. Behind the
postcentral gyrus, on the lateral surface of
the hemisphere, the intraparietal
sulcus divides the rest of the parietal lobe
into superior and inferior parietal lobules.

24. Parietal lobe
Sulci:
 Post-central sulcus.
 Intraparietal sulcus.
Gyri:
 Post-central gyrus.
 Superior parietal gyrus.
 Inferior parietal gyrus.

25. Parietal lobe gyrus
Lateral Surface

Postcentral Gyrus ---- primary somatic area

Superior Parietal Lobule

Inferior Parietal Lobule ---- Wernicke’s area

Supramarginal Gyrus

Angular Gyrus
Medial Surface

Paracentral Lobule

Precuneus

30. Temporal lobe
The temporal lobe lies beneath the lateral
fissure. On its lateral surface the temporal
lobe is divided into three principal gyri
that run roughly parallel to the lateral
fissure: the superior, middle and inferior
temporal gyri. The superior temporal
gyrus includes the primary auditory
cortex.

31. Temporal lobe
Sulci:
 Superior temporal sulcus (parallel
sulcus).
 Inferior temporal sulcus.
Gyri:
 Superior temporal gyrus.
 Middle temporal gyrus.
 Inferior temporal gyrus.

32. Temporal lobe gyrus
Lateral Surface
 Superior Temporal Gyrus
 Middle Temporal Gyrus
 Inferior Temporal Gyrus

Basal Surface
 Occipitotemporal Gyrus

Medial Occipitotemporal Gyrus

Lateral Occipitotemporal Gyrus

36. Occipital lobe
The boundary between the parietal lobe and
occipital lobe is not coincident with a
single sulcus on the lateral surface of the
hemisphere; however, it is clearly marked
by the deep parieto-occipital sulcus on
the medial surface. The occipital lobe does
not bear any important landmarks on its
lateral surface but on the medial surface,
the prominent calcarine sulcus indicates
the location of the primary visual cortex.

37. Occipital lobe
Sulci:
• Superior occipital sulcus (extension of
intraparietal sulcus).
• Inferior occipital sulcus (extension of inferior
temporal sulcus).
Gyri:
• Superior occipital gyrus.
• Middle occipital gyrus.
• Inferior occipital gyrus

38. Occipital lobe gyrus
Lateral Surface

Lateral Occipital Gyrus

Superior Occipital Gyrus

Inferior Occipital Gyrus
Medial Surface

Cuneus

Lingual Gyrus
Basal Surface
 Lateral occipito-temporal gyrus (fusiform gyrus).
 Medial occipito-temporal gyrus (lingual gyrus).

43. Limbic lobe
On the medial surface of the hemisphere, certain
portions of the frontal, parietal and temporal lobes
also constitute components of the limbic system.
Curving around the corpus callosum, and running
parallel to it, lies the cingulate gyrus , separated
from the rest of the hemisphere by the cingulate
sulcus. The cingulate gyrus passes posteriorly and
inferiorly round the posterior portion of the
corpus callosum to become continuous with
the parahippocampal gyrus of the temporal lobe.
Deep to the parahippocampal gyrus, within the
temporal lobe lies the hippocampus.
The cingulate gyrus, parahippocampal gyrus and
hippocampus are referred to as the limbic lobe.

44. Limbic lobe gyrus
Outer Ring

Cingulate Gyrus

Isthmus of Cingulate Gyrus

Parahippocampal Gyrus

Uncus, Uncinate Gyrus
Inner Ring

Hippocampal Formation

Hippocampus, Ammon's Horn

Dentate Gyrus

Fasciolar Gyrus

Supracallosal Gyrus

Subcallosal Area (Parolfactory Area)

48. Insular lobe
• Lies deep in floor of sylvian fissure,
overlapped by frontal, temporal and
parietal.
• The insular lobe is thought to be involved
in sensory and motor visceral functions as
well as taste perception.

49. Insular lobe
Sulci:
Central sulcus.
Short insular sulcus.
Precentral sulcus.
Gyri:
Anterior insular lobule.
Posterior insular lobule.

50. Insular lobe
Anterior insular lobule (short insular gyri):
 Anterior short insular gyrus.
 Middle short insular gyrus.
 Posterior short insular gyrus.
Posterior insular lobule (long insular gyri):
 Anterior long insular gyrus.
 Posterior long insular gyrus.

54. Sulcus and gyrus
Sagittal
Axial
Coronal

55. Signs to identify sulcus in mri
• The midline sulcus sign: The longest
sulcus running horizontally and entering
the interhemispheric fissure is the central
sulcus .
• The M sign: The typical upper case M
shape of the inferior frontal gyrus is
formed by its parts ( orbitalis, triangularis,
and opercularis ).

56. signs
• The bifid post cg sign: Toward the
interhemispheric fissure, the postcentral
gyrus is medially fissured, enclosing the
pars marginalis of the cingulated sulcus
with both legs and thereby forming the
characteristic bifid post cg sign.
• The thin post cg sign: On the surface, the
precentral gyrus has a thicker
anteroposterior diameter compared with
the postcentral gyrus, which is thinner.

57. signs
• The handknob: defined the "handknob " as
1 single -shaped dorsally convex bulge of
the precentral gyrus.
• The upper T sign: The intersection of the
well-identifiable superior frontal sulcus
with the precentral sulcus has the shape of
an upper case T. The pre cg can be found
immediately posterior to this T shape.

58. signs
• The L sign: The sfg terminates in the pre
cg, which runs laterally from the posterior
end of the sfg, therefore together forming
an upper case L.
• The lower T sign: The inferior frontal
sulcus posteriorly terminates in the pre sc,
also in the shape of an upper case T that is
dorsally bordered by the pre cg.

59. signs
• Inverted omega sign : the central sulcus
more likely to have the shape of inverted
omega.
• The bracket sign: The bihemispheric
symmetric pars marginalis of the cingulate
sulcus forms an anteriorly opened bracket.

63. Sagittal

64. Superior frontal gyrus
Cingulate sulcus
Marginal ramus of
Cingulate sulcus
Cingulate gyrus
Paracentral lobule
Superior parietal lobule
Parietooccipital sulcus
Cuneus
Calcarine sulcus
Lingual gyrus
Subcallosal gyrus
Gyrus rectus
NP/MGH
Fastigium, fourth ventricle

65. Superior frontal gyrus
Cingulate sulcus
Precentral gyrus
Cingulate gyrus
Central sulcus
Marginal ramus of
Cingulate sulcus
Superior parietal lobule
Precuneus
Parietooccipital sulcus
Cuneus
Calcarine sulcus
Frontomarginal gyrus
Gyrus rectus
Caudothallamic groove
NP/MGH
Lingual gyrus

66. Precentral
sulcus
Superior frontal gyrus
Central sulcus
Marginal ramus of
Cingulate sulcus
Corona radiata
Superior parietal lobule
Precuneus
Parietooccipital sulcus
Calcarine sulcus
NP/MGH Lingual gyrus
Inferior occipital gyrus

67. Central sulcus
Superior parietal lobule
Parietooccipital sulcus
Frontopolar gyrus
Frontomarginal gyrus
Superior occipital gyrus
Middle occipital gyrus
Medial orbital gyrus
Posterior orbital gyrus
Inferior temporal gyrusNP/MGH
Temporal horn,
lateral ventricle
Lingual gyrus Inferior occipital gyrus

68. Central sulcus
uperior Temporal gyrus
Middle Temporal gyrus
Inferior Temporal gyrus
NP/MGH

69. Central sulcus
Inferior frontal gyrus
Superior parietal
gyrus
Frontomarginal gyrus
Anterior orbital gyrus
Superior occipital
gyrus
Middle occipital
gyrus
Posterior orbital gyrus
Superior Temporal
gyrus
Inferior occipital
gyrus
Middle Temporal gyrus
Inferior Temporal gyrus
NP/MGH
Lingual gyrus

70. Precentral sulcus
Superior frontal sulcus
Central sulcus
Postcentral sulcus
Lateral fissure,
posterior segment
Inferior frontal gyrus,
pars triangularis
Angular gyrus
Inferior frontal gyrus,
pars orbitalis
Superior Temporal gyrus
Superior Temporal sulcus
Middle occipital gyrus
Middle Temporal gyrus
Anterior occipital sulcus
Inferior Temporal gyrus
Inferior occipital gyrus
NP/MGH

71. axial

72. Fusiform gyrus
Superior Temporal gyrus
Middle Temporal gyrus
Inferior Temporal gyrus
NP/MGH

73. Parahippocampal gyrus
Superior Temporal gyrus
Middle Temporal gyrus
Inferior Temporal gyrus
Hippocampal gyrus
NP/MGH

74. Amygdala
Hippocampus
Superior Temporal gyrus
Middle Temporal gyrus
Temporo-occipital fissure
Inferior occipital gyrus
Gyrus descendens
Inferior Temporal gyrus
Lingual gyrus
NP/MGH

75. Gyrus rectus
Medial orbital gyrus
Olfactory sulcus
Subcallosal gyrus
Posterior orbital gyrus
Superior Temporal gyrus
Amygdala
Middle Temporal gyrus
Hippocampus
Inferior Temporal gyrus
Temporo-occipital fissure
Middle occipital gyrus
Gyrus descendens
NP/MGH
Lingual gyrus

76. Superior frontal gyrus
Middle frontal gyrus
Inferior frontal gyrus,
pars orbitalis
Lateral fissure
Inferior frontal gyrus,
pars opercularis
Inferior parietal gyrus
Insula
Lateral fissure
Cingulate gyrus
Superior temporal gyrus
Parieto-occipital fissure
Superior temporal sulcus
Middle temporal gyrus
Calcarine sulcus
Middle occipital gyrus
Superior occipital gyrus
Intra-occipital sulcus
NP/MGH
Cuneus

77. Superior frontal gyrus
Middle frontal
gyrus
Inferior frontal gyrus
Central sulcus
Postcentral gyrus
Lateral fissure
Inferior parietal gyrus
Superior temporal gyrus
Lateral fissure
Superior temporal sulcus
Middle occipital gyrus
Intra-occipital sulcus
Superior occipital gyrus
NP/MGH
Parieto-occipital sulcus

78. Precentral sulcus
Precentral gyrus
Central sulcus
Middle occipital gyrus
Central sulcus
Cuneus
NP/MGH
Superior occipital gyrus
Intra-occipital sulcus

79. Superior frontal gyrus
Middle frontal gyrus
Superior frontal sulcus
Inferior frontal gyrus
Centrum semiovale
Central sulcus
Central sulcus
Postcentral sulcus
Postcentral sulcus
Supramarginal gyrus
Intraparietal sulcus
Angular gyrus
Parietooccipital sulcus
Superior parietal gyrus
NP/MGH
Precuneus

80. Superior frontal gyrus
Middle frontal gyrus
Superior frontal sulcus
Central sulcus
Central sulcus
Supramarginal gyrus
Postcentral sulcus
Intraparietal sulcus
Angular gyrus
Pars marginalis
Intraparietal sulcus
Superior parietal gyrus
NP/MGH

81. coronal

82. Interhemispheric Fissure
Inferior Frontal gyrus
Superior Frontal gyrus
Middle Frontal gyrus
Inferior Frontal gyrus
Gyrus rectus
Medial Orbital gyrus
Olfactory bulb
NP/MGH

83. Superior Frontal gyrus
Forceps
minor
Superior Frontal sulcus
Middle Frontal gyrus
Inferior Frontal gyrus
Lateral orbital sulcus
Medial Orbital gyrus
Lateral orbital gyrus
Gyrus rectus
Anterior Orbital gyrus
Olfactory Sulcus
NP/MGH

84. Circular insular sulcus Cingulate gyrus
Superior Frontal
gyrus
short insular gyrus
Middle Frontal gyrus
Inferior Frontal sulcus
Inferior Frontal gyrus
pars opercularis
Sylvian Fissure
Posterior Orbital gyrus
Middle Temporal gyrus
Olfactory Sulcus
Superior Temporal gyrus
Inferior Temporal gyrus
NP/MGH
Gyrus rectus
Medial Orbital gyrus

85. Superior Frontal sulcus
Superior Frontal
gyrus
Cingulate sulcus
Middle Frontal gyrus
Precentral
sulcus
Precentral gyrus
Sylvian Fissure
Superior Temporal
gyrus
Superior Temporal Sulcus
Middle Temporal gyrus
Amygdala
NP/MGH
Anterior commissure
Inferior Temporal gyrus

86. Superior Frontal
gyrus
Middle Frontal gyrus
Central Sulcus
Superior Temporal gyrus
Hippocampus
Middle Temporal
gyrus
Inferior Temporal gyrus
Parahippocampal gyrus
CA1, cornu ammonis
NP/MGH
Fusiform gyrus

87. Postcentral gyrus
Central Sulcus
Intraparietal sulcus
Paracentral lobule
Intraparietal sulcus
Cingulate gyrus
Supramarginal gyrus
Superior Temporal gyrus
Middle Temporal
gyrus
Inferior Temporal gyrus
Fusiform gyrus
Parahippocampal gyrus
Collateral sulcus
NP/MGH

88. Paracentral lobule
Central sulcus
Superior Temporal gyrus
Middle Temporal gyrus
Inferior temporal gyrus
Fusiform gyrus
NP/MGH

89. Paracentral lobule
Postcentral gyrus
Central sulcus
Intraparietal sulcus
Supramarginal gyrus
Middle temporal gyrus
Inferior temporal gyrus
Fusiform gyrus
Calcarine sulcus
Lingual gyrus
NP/MGH
Cingulate gyrus

90. Thank u 