Surfaces, lobes, sulci, gyri of cerebral hemispheres The cerebral hemispheres constitute the largest part of the brain



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Surfaces, lobes, sulci, gyri of cerebral hemispheres

  • The cerebral hemispheres constitute the largest part of the brain

  • Divided into right and left hemispheres.

  • The hemispheres are separated medially by a deep cleft, named the longitudinal cerebral fissure

  • Linked by corpus callosum.

Surfaces of cerebral hemispheres

  • Lateral surface:

  • convex

  • Medial surface

  • flat and vertical

  • Separated by longitudinal fissure

  • Inferior surface

  • Anterior = orbital surface of the frontal lobe

  • Middle = under surface of the temporal lobe

  • Posterior = tentorial surface

Borders of hemispheres

  • 3 surfaces are separated by the following borders:

  • (a) Supero-medial, between the lateral and medial surfaces.

  • (b) Infero-lateral, between the lateral and inferior surfaces; the anterior part of this border separating the lateral from the orbital surface, is known as the superciliary border.

  • (c) Medial occipital, separating the medial and tentorial surfaces.

  • (d) Medial orbital, separating the orbital from the medial surface

Poles of cerebral hemispheres

  • Frontal pole

  • The anterior end of the hemisphere

  • Occipital pole

  • Posterior end of hemisphere

  • Temporal pole

Sulcus and gyrus of cerebral hemispheres

  • Sulcus means "furrow“

  • Depression or fissure in the surface of the brain

  • Large furrows (sulci) that divide the brain into lobes are often called fissures.

  • Gyrus ridge

  • Irregular eminences on the surface of brain formed by sulci

Interlobular sulci of cerebral hemispheres

  • Central sulcus

  • Middle of the lateral surface

  • Divides frontal and parietal lobe

  • Precentral gyrus contains motor area

  • Postcentral gyrus contain sensory area.

  • Lateral sulcus

  • Parieto-occipital sulcus

  • lateral surface = 5cm in front of occipital pole

  • Medial surface



  • Calcarine sulcus

Lobes of cerebral hemispheres

  • Frontal lobe

  • Three sulci divides it into four gyri

  • Precentral sulcus

  • Superior frontal sulcus

  • Inferior frontal sulcus

  • Superior frontal gyrus

  • Middle frontal gyrus

  • Inferior frontal gyrus

  • Precentral gyrus

Parietal lobe

  • 2 sulci divides into 3 gyri

  • Post central sulcus

  • Intraparietal sulcus

  • Post central gyrus

  • Supra parietal lobule

  • Infraparietal lobule

  • Plays role in integrating sensory information from various parts of the body, knowledge of numbers and their relations, and in the manipulation of objects.

Temporal lobe

  • 2 sulci divides it into 3 gyri

  • Superior temporal sulcus

  • Middle temporal sulcus

  • Superior temporal gyrus

  • Mid temporal gyrus

  • Inferior temporal gyrus

Occipital lobe

  • Smallest lobe

  • Lateral occipital gyri

  • Lateral occipital sulci

  • Visual processing cortex

Medial and inferior surface

  • Important structures on the medial surface

  • Corpus callosum

  • Cingulate gyrus

  • Callosal gyrus

  • Paracentral lobule

  • Precuneus

  • Cuneus

  • Collateral sulcus

  • Medial occipitotemporal gyrus

Corpus callosum

  • Bundle of axons

  • It connects the left and right cerebral hemispheres and facilitates interhemispheric communication

Cingulate gyrus

  • Cingulate gyrus

  • Starts beneath the corpus callosum and goes back above it and ends at the posterior end of it.

  • Callosal sulcus

  • Cingulate sulcus

  • Separates cingulate gyrus from superior frontal gyrus

Paracentral lobule

  • Area of brain that surrounds the indentation formed by the central sulcus on the superior border

  • Anterior part = precentral gyrus

  • Posterior part = postcentral gyrus

Cuneus and precuneus

  • Precuneus

  • Cuneus

Collateral sulcus and lingual gyrus

  • On inferior surface

  • Lingual gyrus

  • Between collateral sulcus and calcarine sulcus

  • Parahippocampal gyrus

  • Anterior to lingual gyrus

Medial occipito-temporal gyrus

  • From occipital pole to temporal pole

  • Continuous with inferior temporal gyrus



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