4. Deep Structures of the Cerebral Hemispheres
1.
Lateral Ventricles
-
separated by septum pellucidum
-
connected to 3rd ventricle by interventricular foramina of Monro
a.
anterior horns
b.
body
- parietal lobe
c.
posterior
(occipital) horn
- occipital lobe
d.
inferior horn
- temporal lobe
2.
Deep nuclei (basal
ganglia) = telencephalic extrapyramidal motor system; (substantial nigra = mesencephalic extrapyramidal motor system)
- corpus striatum = caudate, putamen,
globus pallidus
- neostriatum = caudate and putamen
- lentiform nucleus = putamen and globus pallidus
a.
Caudate
- tail ends in amygdala (temporal)
b.
Putamen
c.
Globus Pallidus
d.
fornix
-
connects hippocampus
(temporal lobe) with mammillary bodies (hypothalamus)
3.
Underlying White
Matter
a.
commissural
i.
corpus callosum
ii.
anterior commissure
- larger in homosexual men
iii.
posterior commissure
-
crossing fibers for pupillary light reflex
b.
association
i.
long (much
redundancy)
1.
superior
longitudinal fasciculus
a.
arcuate fasciculus (connects Broca’s 44,45; angular and supramarginal
39,40; Wernicke’s 22)
-
part of the superior longitudinal fasciculus
- conduction aphasia
2.
inferior
longitudinal fasciculus
- inferior continuation
3.
uncinate fasciculus
- common site of seizures
4.
cingulum
- fibers travel perpendicular to corpus callosum
- part of limbic system (connects hippocampus, etc.)
ii.
short
1.
arcuate fibers
c.
projection (corona
radiata)
i.
internal capsule
-
supplied by MCA (isolated limbs can be affected by CVA)
1.
anterior limb
(pre-frontal)
2.
genu limb
- cortico-bulbar fibers = UMN’s; cell
bodies of origin: Brodmann’s 4,8
- terminate in motor nuclei of cranial nerves
3.
posterior limb
- cortico-spinal
tract (Area 4)
4.
retrolenticular limb
ii.
external capsule
iii.
extreme external
capsule