The document describes the anatomy of the brain including sulci and gyri. It discusses typical continuous fissures such as the interhemispheric fissure and sylvian fissure. It then describes the lobes of the brain including the frontal, parietal, temporal, occipital and limbic lobes. Key sulci and gyri are identified for each lobe on the lateral, medial and basal surfaces of the brain. Signs to identify sulci on MRI are also provided.

1. ANATOMY OF BRAIN
SULCUS AND GYRUS

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 up to corpus callosum
Divides brain into two hemisphere

5. Deep, mostly horizontal
Insula is buried within it
Separates temporal lobe from parietal and frontal lobes
SYLVIAN FISSURE

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)
Separates 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

22. 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.

23. PARIETAL LOBE
SULCI:
Post-central sulcus.
Intraparietal sulcus.
GYRI:
Post-central gyrus.
Superior parietal gyrus.
Inferior parietal gyrus.

24. 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

29. 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.
TEMPORAL LOBE

30. Sulci:
Superior temporal sulcus (parallel sulcus).
Inferior temporal sulcus.
Gyri:
Superior temporal gyrus.
Middle temporal gyrus.
Inferior temporal gyrus.
TEMPORAL LOBE

31. Lateral Surface
Superior Temporal Gyrus
Middle Temporal Gyrus
Inferior Temporal Gyrus
Basal Surface
Occipitotemporal Gyrus
Medial Occipitotemporal Gyrus
Lateral Occipitotemporal Gyrus
TEMPORAL LOBE GYRUS

35. 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.

36. 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

37. 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).
OCCIPITAL LOBE GYRUS

42. 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.

43. 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

47. 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.
INSULAR LOBE

48. INSULAR LOBE
Sulci:
Central sulcus.
Short insular sulcus.
Precentral sulcus.
Gyri:
Anterior insular lobule.
Posterior insular lobule.

49. 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.
INSULAR LOBE

53. SULCUS AND GYRUS
Coronal
Axial
Sagittal

54. 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 ).

55. 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.
SIGNS

56. 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.

57. 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.
SIGNS

58. 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.
SIGNS

62. SAGITTAL

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

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

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

66. Frontopolar gyrus
Frontomarginal
gyrus
Medial orbital gyrus
Posterior orbital gyrus
Inferior temporal gyrus Temporal horn,
Lateral ventricle
Lingual gyrus Inferior occipital gyrus
Middle occipital
gyrus
Superior occipital
gyrus
Parietooccipital sulcus
Superior parietal
lobule
Central sulcus

67. Central sulcus
Inferior temporal gyrus
Superior temporal
gyrus
MiddleTemporal gyrus

68. Central sulcus Superior parietal
gyrus
Superior occipital
gyrus
Middle occipital
gyrus
Inferior occipital
gyrus
Lingual gyrus
Inferior temporal gyrus
MiddleTemporal gyrus
Superior temporal
gyrus
Posterior orbital gyrus
Anterior orbital gyrus
Frontomarginal gyrus
Inferior frontal gyrus

69. Inferior frontal gyrus,
pars triangularis
Inferior frontal gyrus,
pars orbitalis
Superior Temporal gyrus
SuperiorTemporal sulcus
MiddleTemporal gyrus
InferiorTemporal gyrus
Inferior occipital gyrus
Anterior occipital sulcus
Middle occipital gyrus
Angular gyrus
Lateral fissure,
posterior segment
Postcentral sulcus
Central sulcus
Precentral sulcus
Superior frontal sulcus

70. AXIAL

71. Fusiform gyrus
InferiorTemporal gyrus
MiddleTemporal gyrus
SuperiorTemporal gyrus

72. Hippocampal gyrus
Parahippocampal gyrus
Superior Temporal gyrus
MiddleTemporal gyrus
InferiorTemporal gyrus

73. Amygdala Hippocampus
SuperiorTemporal gyrus
MiddleTemporal gyrus
InferiorTemporal gyrus
Lingual gyrus
Gyrus descendens
Inferior occipital gyrus
Temporo-occipital fissure

74. Hippocampus
Amygdala
Subcallosal gyrus
Olfactory sulcus
Gyrus rectus
Medial orbital gyrus
Posterior orbital gyrus
SuperiorTemporal gyrus
MiddleTemporal gyrus
InferiorTemporal gyrus
Temporo-occipital fissure
Middle occipital gyrus Gyrus descendens Lingual gyrus

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

76. Middle frontal gyrus
Superior frontal gyrus
Inferior frontal gyrus
Postcentral gyrus
Inferior parietal gyrus
Lateral fissure
Superior temporal sulcus
Parieto-occipital sulcus
Superior occipital gyrus
Intra-occipital sulcus
Middle occipital gyrus
Superior temporal gyrus
Lateral fissure
Central sulcus

77. Superior occipital gyrus
Cuneus
Intra-occipital sulcus
Central sulcus
Central sulcus
Middle occipital gyrus
Precentral gyrus
Precentral sulcus

78. Superior frontal gyrus
Superior frontal sulcus
Centrum semiovale
Central sulcus
Postcentral sulcus
Intraparietal sulcus
Angular gyrus
Superior parietal gyrus
Precuneus
Parietooccipital sulcus
Supramarginal gyrus
Postcentral sulcus
Central sulcus
Inferior frontal gyrus
Middle frontal gyrus

79. Superior frontal gyrus
Superior frontal sulcus
Middle frontal gyrus
Central sulcus
Central sulcus
Postcentral sulcus
Intraparietal sulcus
Pars marginalis
Superior parietal gyrus
Intraparietal sulcus
Angular gyrus
Supramarginal gyrus

80. CORONAL

81. Interhemispheric Fissure
Inferior Frontal gyrus
Olfactory bulb
Superior frontal gyrus
Middle frontal gyrus
Inferior frontal gyrus
Middle orbital gyrus
Gyrus rectus

82. Superior frontal gyrus
Superior frontal sulcus
Middle frontal gyrus
Inferior frontal gyrus
Forceps minor
Lateral orbital sulcus
Lateral orbital gyrus
medial orbital sulcus
Olfactory sulcus
Gyrus rectus
Anterior Orbital gyrus

83. Circular insular sulcus Cingulate gyrus
Superior Frontal
gyrus Middle Frontal gyrus
Inferior Frontal sulcus
Inferior Frontal gyrus
pars opercularis
Sylvian Fissure
Posterior Orbital gyrus
medial orbital gyrus
Gyrus rectus
Olfactory sulcus
Superior temporal gyrus
Inferior temporal gyrus
Middle temporal gyrus
short insular
gyrus

84. Superior frontal sulcus
Superior frontal gyrus Cingulate gyrus
Precentral sulcus
Precentral gyrus
Sylvian Fissure
Middle frontal gyrus
Superior temporal gyrus
Superior temporal sulcus
Middle temporal gyrus
Amygdala
Anterior commissure
Inferior temporal gyrus

85. Hippocampus
Central sulcus
Middle Frontal gyrus
Superior Frontal gyrus
Superior temporal gyrus
Middle temporal gyrus
Inferior temporal gyrus
Fusiform gyrus
CA1, cornuammonis
Parahippocampal gyrus

86. Supramarginal gyrus
Intraparietal sulcus
Cingulate gyrus
Paracentral lobule
Central Sulcus
Postcentral gyrus
Intraparietal sulcus
Superior temporal gyrus
Middle temporal gyrus
Inferior temporal gyrus
Fusiform gyrus
Parahippocampal gyrus Collateral sulcus

87. Paracentral lobule
Central Sulcus
Superior temporal gyrus
Middle temporal gyrus
Inferior temporal gyrus
Fusiform gyrus

88. Paracentral lobule
Central Sulcus
Postcentral gyrus
Supramarginal gyrus
Intraparietal sulcus
Middle temporal gyrus
Inferior temporal gyrus
Cingulate gyrus
Calcarine sulcus
Lingual gyrus
Fusiform gyrus

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