surface anatomy of the brain
TRANSCRIPT
Surface anatomy of the brain
Dr Hytham Nafady
CT anatomy of the lobes of cerebral hemisphere
ANATOMYANATOMY Inferior sections
T
ANATOMYANATOMY
Ventricular sections
3rd BGFH
OH
Body
O
P
F
Superior sections
P
F
ANATOMYANATOMY
Lobar borders
Surface anatomy of
the lateral surface
Lateral surface of cerebral hemisphere
Sylvian fissure
Sylvian fissure
Frontal lobe
Frontal lobe
Superior frontal sulcus bifurcates to form superior precentral gyrus
Inferior frontal sulcus bifurcates to form inferior precentral gyrus
Superior frontal gyrus
• Rectangular (Bar shaped)
• Forms the upper most margin of the frontal lobe.
Inferior frontal gyrus
• Triangular gyrus (M shaped).
Divided by the anterior horizontal ramus and anterior ascending ramus into 3 portions.
1. Pars orbitalis.
2. Pars triangularis.
3. Pars opercularis.
Inferior frontal gyrus
Inferior frontal gyrus
Temporal lobe
Temporal lobe
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Temporal Sulci
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Temporal Sulci
Superior temporal sulcus
Termination:
Angular sulcus (as it is straddled by the angular gyrus).
Inferior temporal sulcus
Termination:
become continuous with the inferior occipital sulcus.
Parietal lobe
Post-central gyrus:• Merges with the pre-central gyrus below the central
sulcus along the sub-central gyrus just above the sylvian fissure.
• Merges with the pre-central gyrus above the central sulcus along the para-central lobule on the medial surface of the hemisphere.
• The pre-central & post-central gyri form a continuous band of tissue around the central sulcus
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Central, Postcentral and Precentral Sulci
ascending bandof the cingulate
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Central, Postcentral and Precentral Sulci
ascending bandof the cingulate
Occipital lobe
Occipital sulci
Insular lobe
Insular lobe
Sulci:
Central sulcus.
Short insular sulcus.
Precentral sulcus.
Gyri:
Anterior insular lobule.
Posterior insular lobule.
Insular lobe
Surface anatomy of
the medial surface
Sulci of the medial surface
1. Callosal sulcus.2. Cingulate sulcus.3. Rostral sulci.4. Paracentral sulcus.5. Subparietal sulcus.6. Parieto-occipital sulcus.7. Calcarine sulcus.8. Anterior calcarine sulcus.
Gyri of the medial surface
Gyri of the medial surface
Cingulate SulcusDivides cingulate gyrus from precuneus and paracentral lobule
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Parieto-occipital Fissure and Calcarine Sulcus
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Parieto-occipital Fissure and Calcarine Sulcus
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Medial Frontal gyrus
-medial surface of superior frontal gyrus
Surface anatomy of
the inferior surface
Surface anatomy of the inferior surface
Temporo-occipital lobe
3 sulci:1. Lateral occipito-temporal sulcus.2. Medial occipito-temporal sulcus (collateral sulcus).3. Anterior calcarine sulcus.4 gyri:1. .2. Lateral occipito-temporal gyrus (fusiform gyrus).3. .4. (limbic lobe).
Localization of the central sulcus and related gyri
Axial plane Sagittal plane
Hand knob Hook sign
Gyral & cortical thickness.
Inferior frontal gyrus
Bracket sign Pars margianlis
L sign
Ω
M
L sign
• Superior frontal sulcus and precentral sulcus form an L.
Localization of the transverse temporal gyrus (Heschl’s gyrus)
Sagittal plane Supratemporal surface just lateral to the insula.
Omega shaped.
Coronal plane At the level of tent like convergence of the 2 fornices.
Axial plane At the level of massa intermedia.
Characteristic anterolateral course.
Broca’s area• Motor speech area.• Area 44.• Pars orpecularis & pars triangularis of the inferior frontal
gyrus in the dominant hemisphere.• Lesions of Broca’s area produce motor aphasia.• Auditory hallucinations are associated with increased
metabolism in Broca’s area & its analogue in the non dominant hemisphere.
Many women, but not men, have motor speech areas in the inferior frontal gyri bilaterally (Pugh et al. 1996; Shaywitz et al. 1995)
Broca’s infarction
• Acute infarct in the left inferior frontal gyrus in a patient with expressive aphasia.
Dronker’s area
• Precentral gyrus (posterior short gyrus) of the anterior lobule of the insula.
• Lesions of Dronker’s area produce speech apraxia.
Wernicke’s area
• Sensory speech area.
• Area 22.
• Posterior part of superior temporal sulcus.
Auditory association area
• Angular gyrus
