WHITE MATTER OF CEREBRUM
WHITE MATTER OF CEREBRUM
- White matter of cerebrum hemisphere is divisible into 3 fiber systems:-
-
Association fibers: Connect the functional area of one cerebral hemisphere to other in the same cerebral hemisphere.
-
Projection fibers: Connect cerebral cortex to other parts of brain & spinal cord.
-
Commissural fibers: Connect same areas b/w the two cerebral hemispheres. Corpus callosum is largest of these.
|
Association fibers |
Projection fibers |
Commissural fibers |
|
a) Cingulum |
a) FimbrIa |
1. Anterior commissure |
|
b) Superior longitudinal fasciculus |
b) Fornix |
2. Hippocampal commissure |
|
c) Inferior longitudinal fasciculus |
c) Corona radiata |
3. Habenular commissure |
|
d) Uncinate fasciculus |
d) Internal capsule |
4. Posterior commissure |
|
5. Corpus callosum |
CORPUS CALLOSUM
- Largest commissure & largest fibre pathway of brain.
- Connects homotopic (symmetrical) & hetrotopic (anatomically different but functionally similar) areas of two hemispheres.
- Corpus callosum is around 10cm long.
- Has 4 parts from behind forwards:
-
Splenium
-
Trunk (body)
-
Genu
-
Rostrum
- The splenium is the enlarged posterior end & lies 6 cm in front of occipital pole.
- The genu lies 4 cm behind the frontal pole.
- Fibers passing through rostrum connect orbital surface of both hemispheres.
- Fibers of genu (forceps minor) connect medial & lateral surfaces of frontal lobe
- Fibers passing through the trunk (body) are projected bilaterally to wide areas of cerebral cortex.
- Fibers passing through splenium (forces major) connects the occipital lobes of 2 hemispheres.
Exam Important
- Largest commissural fibers are seen in Corpus callosum.
- Corpus callosum connect same areas of two cerebral hemispheres.
- Rostral end of the corpus callosum called Genu.
- Rostrum connect orbital surface of both hemispheres.
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