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 Brocaís 44,45; angular and supramarginal 39,40; Wernickeís 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 = UMNís; cell bodies of origin: Brodmannís 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