NETTER - Neuroscience Flash Cards

Axial Sections through the Forebrain:
Head of the Caudate Nucleus
and Midthalamus
1. Genu of the corpus
callosum
2. Head of the caudate
nucleus
3. Anterior horn of the lateral
ventricle
4. Globus pallidus
5. Putamen
6. Optic radiations
7. Anterior limb of the internal
capsule
8. Genu of the internal
capsule
9. Posterior limb of the
internal capsule
10. Thalamus
11. Splenium of the corpus
callosum
Comment: The internal capsule reciprocally interconnects cortex
and more caudal structures. The anterior limb carries cortical
projections to the striatum and pontine nuclei (corticopontocerebellar
system) and has reciprocal connections with important thalamic
structures such as the medial dorsal and anterior nuclei. The genu
carries corticobulbar axons destined for brain stem nuclei regulation,
particularly motor cranial nerve nuclei. The posterior limb conveys
major descending corticospinal, corticorubral, and corticoreticular
fibers; major ascending sensory connections for the somatosensory
and trigeminal system; and, posteriorly, visual and auditory
radiations. The internal capsule is susceptible to middle cerebral
artery lesions, particularly narrow lenticulostriate arteries. A vascular
lesion of the posterior limb of the internal capsule results (long term,
after resolution of the flaccid stage of shock) in contralateral spastic
hemiplegia with hypertonus, hyperreflexia, flexed posture of the
upper limb and extended and internally rotated posture of the lower
limb, and pathological reflexes (e.g., plantar extensor response,
possibly clonus). Such a lesion also produces loss of sensation on
the contralateral body. If the genu of the internal capsule is involved
in the lesion, a contralateral drooping lower face (central facial palsy)
is seem due to removal of control of the corticobulbar system from
regulation of the contralateral facial nerve motor nucleus for muscles
of facial expression for the lower face.
Regional Neuroscience See book 13.6B