Other fibers, however, never decussate and synapse in the ipsilateral facial nucleus. Some fibers descend lower than the nucleus, cross to the other side, and then ascend to that side's nucleus (recurrent bundle of Dejerine). Continuing through the basal portion of the pons with the pyramidal tract, most fibers cross in the caudal pons to reach the contralateral facial motor nucleus. When the fibers reach the midbrain, they join the medial third of the cerebral peduncle. These fibers join the corticobulbar tract and pass caudally within the posterior aspect of the internal capsule near its genu. Motor cortex for the tongue is next in line. The cortical representation of the face, from uppermost cortex to lower, begins with the forehead, followed by the periorbital muscles, midface, and perioral muscles. The cortical projections ( corona radiata) originate from pyramidal neurons located in the lower third of the precentral gyrus of the frontal motor cortex. Fetterman, in Textbook of Clinical Neurology (Third Edition), 2007 Upper Motor Neuron: Supranuclear Control 95 Dystonia may arise from lesions at several different sites in the basal ganglia and thalamus.Äerald E. 94 Medial pallidal infarction also may cause contralateral dystonia. Restricted pallidal infarction causes acute memory loss, abulia, loss of drive, reduced emotional expression, and reduced spontaneity in some patients, and disinhibition and obsessive-compulsive symptoms in others. Language dysfunction with micrographia and expressive aphasia may follow left-sided lesions, 86 and hemineglect may follow right-sided lesions. 88 Restricted putaminal infarction may cause amnesia falling to one side and hemidystonia, chorea, or facial palsy. Restricted caudate infarction may cause behavioral and cognitive deficits consisting of abulia, restlessness, agitation, disinhibition, and mood changes, sometimes associated with dysarthria and movement disorders. Single lacunes may be silent, but may cause pure dysarthria or sometimes mild frontal lobe signs or weakness of proximal movements. Restricted anterior limb infarcts of the internal capsule, completely sparing the adjacent striatum, corona radiata, and posterior limb, are rare. The syndrome may variously consist of pure hemiplegia, sensory loss in the face and arm, dysarthria–clumsy hand syndrome of the AchorA, and dysphasia or hemineglect. This site is vulnerable because it is at the junction of the lateral lenticulostriate artery perforators with the long medullary penetrating arteries from the superficial MCA and the superior limit posteriorly of the distribution of the AchorA in the posterior limb of the internal capsule. Restricted corona radiata infarcts can occur near the lateral angle of the lateral ventricles. William DeMyer, in Stroke in Children and Young Adults (Second Edition), 2009 Clinical Syndromes of Restricted Infarcts of the Lateral Lenticulostriate Arteries
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |