1 / 18

Brain Topography

Brain Topography. Dr. Nimir Dr. Safaa. Objectives Demarcate the major lobes, gyri and sulci of the cerebral hemisphere . Describe the organization of the cerebral hemisphere into cerebral cortex ,white matter and nuclei

shelby
Download Presentation

Brain Topography

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Brain Topography • Dr. Nimir • Dr. Safaa

  2. Objectives • Demarcate the major lobes, gyri and sulci of the cerebral hemisphere. • Describe the organization of the cerebral hemisphere into cerebral cortex ,white matter and nuclei • Describe the types of fibers in the white matter of the cerebral hemisphere: projection (internal capsule), commissural and association fibers.

  3. The brain is divided into: • 1- Forebrain (Telencephalon= cerebrum & diencephalon). • 2- Midbrain. • 3- Hindbrain (pons ,medulla oblongata, cerebellum). • Cerebrum (cerebral hemispheres & basal ganglia ). • Cerebral hemispheres are seperated by longitudinal fissure into left & right which are connected by corpus callosum.

  4. Each cerebral hemisphere has 3 surfaces: • Superolateral. • Medial. • Inferior. • Each cerebral hemisphere has 3 poles: • Frontal pole. • Temporal pole. • Occipital pole.

  5. To increase the surface area the cerebral cortex is thrown into folds or gyri, which are separated from each other by sulci or fissures. • Each cerebral hemisphere is divided by central, parieto-occipital,lateral and calcarine sulci into frontal, parietal, temporal, and occipital lobes.

  6. Superolateralsurface • Frontal lobe: • Is anterior to the central sulcus and superior to the lateral sulcus. • Its superolateral surface is divided by three sulciinto four gyri. • Precentralsulcusruns parallel to central sulcus, and precentralgyruslies between them. • Extending anteriorly from precentralsulcus are superior and inferior frontal sulci. • Superior frontal gyruslies above superior sulcus. • Middle frontal gyruslies between superior and inferior sulci. • Inferior frontal gyruslies below inferior sulcus.

  7. Parietal lobe: • Is posterior to central sulcus, superior to lateral sulcusand anterior to parieto-occipital sulcus. • Its lateral surface is divided by two sulci into three gyri. • Postcentralsulcus runs parallel to central sulcus, and postcentralgyruslies between them. • Running posteriorly from the middle of the postcentral sulcus is intraparietalsulcus. Superior to intraparietal sulcus is superior parietal lobule (gyrus). • Inferior to the intraparietal sulcus is the inferior parietal lobule (gyrus).

  8. Temporal lobe: • Is inferior to the lateral sulcus. • Its lateral surface is divided into three gyri by two sulci. • The superior and middle temporal sulci run parallel to lateral sulcus and divide temporal lobe into superior, middle, and inferior temporal gyri. • Occipital lobe: • Is behind the parieto-occipital sulcus.

  9. Medial surfaces • Corpus callosum is the largest commissure. • Cingulate gyrusis above corpus callosum,separatedfrom it by callosalsulcus and from medial frontal gyrusby cingulate sulcus. • Paracentral lobule anteriorly is part of precentralgyrusposteriorly is part of postcentralgyrus. • Precuneus is part of parietal lobe. • Cuneuswhich is part of occipital lobe, is between parieto-occipita & calcrinesulci.

  10. Inferior surface • Collateral sulcus runs anteriorly below the calcarine sulcus. • Between collateral sulcus and calcarine sulcus is lingual gyrus. • Anterior to lingual gyrus is parahippocampalgyrus which terminates in front as uncus. • Medial occipitotemporalgyrusis bounded medially by collateraland rhinal sulci and laterally by occipitotemporalsulcus which separate it from lateral occipitotemporalgyrus. • On inferior surface of frontal lobe is olfactory sulcuswith olfactory bulb and orbital gyri.

  11. Gray matter consists of nerve cells(neurons) embedded in neuroglia. • White matter consists of nerve fibers (axons) embedded in neuroglia. • In cerebral hemispheres gray mater is seen in cerebral cortex & basal ganglia.

  12. White mater fibers are classified into three groups according to their connections: • 1. Commissural fibers. • 2. Association fibers. • 3. Projection fibers.

  13. 1. Commissural fibers: • Connect corresponding regions of the two hemispheres. They are: • Corpus callosum(splenium ,body, genu, rostrum). • Anterior commissure. • Posterior commissure. • Fornix. • Habenularcommissure.

  14. 2. Association fibers: • Connect various cortical regions within the same hemisphere and may be divided into short and long. • Shortassociation fibers connect adjacent gyri. • Longassociation fibers: • Uncinatefasciculus connects motor speech area & inferior surface of the frontal lobe to temporal lobe.

  15. Cingulumwithin cingulate gyrus connects frontal and parietal lobes to parahippocampal and temporal cortical regions. • Superior longitudinal fasciculus connects anterior part of the frontal lobe to the occipital and temporal lobes. • Inferior longitudinal fasciculus connects occipital lobe to temporal lobe. • Fronto-occipital fasciculus connects frontal lobe to occipital and temporal lobes.

  16. 3. Projection fibersare afferent and efferent nerve fibers passing to and from the brainstem & spinal cord to the entire cerebral cortex. • Mainly pass within the internal capsule between caudate nucleus &thalamus medially &lentiformnucleus laterally. • The fibers radiate to cortical areas as corona radiata.

More Related