8/28/2023 0 Comments Pica artery full formBinocular oblique diplopia – secondary to skew deviation from disruption of otolithic input at the level of the brainstem.Oscillopsia due to rotary nystagmus – due to disruption of communicating neurons between brainstem and inferior cerebellar peduncle patient experiences oscillopsia, nausea, vomiting, vertigo, dizziness.Horner syndrome (miosis, ptosis, upside down ptosis, anhidrosis)– due to disruption of the oculosympathetic chain, which descends through the lateral medulla.Other rarer causes such as vertebral artery dissection especially in predisposed younger individuals with Ehlers-Danlos Syndrome, Marfan syndrome, fibromuscular dysplasia and hypoplastic vertebral artery have been noted in prior literature. Primary etiologies include atherosclerosis, hypertension and other vasculopathic risk factors. While most commonly due to PICA occlusion, other arteries, such as the vertebral artery or branches of PICA, can be involved as well. WS is most commonly due to an occlusion of the PICA, resulting in ischemia and infarction of the lateral medulla. The blood flow and the cross-sectional anatomy of the medulla are illustrated in figures 1 and 2.įigure 2: cross-sectional anatomy of medulla including all nuclei and tracts Etiology The anterior spinal artery has its own median medullary branch, which perfuses the anteromedial region of the medulla. The anterior spinal artery provides blood flow to the remainder of the medulla. The medial medullary branch of PICA perfuses the anterior lateral medulla, and the lateral medullary branch perfuses the lateral medulla. The dorsal medullary branch of PICA perfuses the posterior medulla. The vertebral artery supplies the posterior inferior cerebellar artery (PICA), which has 3 main branches: the dorsal, medial, and lateral medullary branches. The primary blood supply to the medulla comes from the vertebral arteries. These regions are divided based on their differing arterial supply. The medulla can be divided into 4 regions: anteromedial, anterolateral, lateral, and posterior ( Figure 1). This monograph highlights the neuro-ophthalmic presentations for the WS. WS is typically due to ischemia from a vertebral artery or posterior inferior cerebellar artery infarction. Wallenberg syndrome (WS) is a neurological disorder that is due to damage to the lateral portion of the medulla oblongata (i.e., the lateral medullary syndrome). 2.2 Systemic Manifestations (Table 1 ).It has a variable territory depending on the size of the AICA ( AICA-PICA dominance). Note: occasionally, a small vertebral artery will terminate into a common AICA-PICA complex. The posterior inferior cerebellar artery gives off the following arteries: Supplies the vermis and adjacent hemisphere The main trunk of the posterior inferior cerebellar artery usually bifurcates somewhere along the margin of the cerebellar tonsil into Supplies branches to the cerebellar surface Marks the transition between the proximal (medulla-supplying) and distal (cerebellum-supplying) parts of the posterior inferior cerebellar arteryĬourses in the cleft between the tela choroidea, inferior medullary velum rostrally, and superior pole of the cerebellar tonsil caudallyĬontains the cranial loop, also known as the choroid point or choroid arch, an upward convex loop that has a constant relation to the 4 th ventricle and gives rise to choroidal arteries Variably courses (ascending or descending) along the side of the medulla near or between the origins of the 9 th, 10 th, and 11 th cranial nerve rootsĬourses along the posterolateral surface of the medulla and inferior cerebellar tonsilĬontains the caudal loop, a downward convex loop that mostly remain superior to the foramen magnum but occasionally extend below it 6,7:Ĭourses along the front of the medulla at the level of the inferior olive The segmental anatomy was defined microsurgically by Lister et al. Occasionally arises from a common origin with the anterior inferior cerebellar artery ~20% arise extracranially, inferior to the foramen magnumġ0% arise from the basilar rather than vertebral artery The PICA is a paired artery that originates from the vertebral artery V4 segment.
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