DR Medhat MRCP

o Each hemisphere is formed of 2 layers
‣ Cerebral cortex (outer grey matter): contains functional areas.
‣ Basal ganglia ,thalamus & hypoyhalamus (deeper in the white matter).
B. Brain stem :
o It`s formed of : 1. Midbrain 2. Pons 3. Medulla oblongata
o It`s connected to cerebral hemispheres by 2 cerebral peduncles & to the
cerebellum, on each side, by superior,middle & inferior cerebellar peduncles
o It contains group of nerve cells (grey matter)intermingled with several
ascending & descending fibres (white matter).
o The motor nuclei of cranial nerves are arranged in the brainstem as follows:
‣ Cr 3 & 4
in midbrain.
‣ Cr 5,6 &7
in pons.
‣ Cr 9,10,11,&12 in medulla
NB : Cr 1, 2 & 8 are sensory nerves concerned with special sensations perceived
in special areas of cerebral cortex so ,Cr1,2& 8 have no motor nuclei
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