Circle Of Willis

Question 1

Occlusion of this artery results in the following clinical symptoms: vertigo, nausea, vomiting, nystagmus, ipsilateral features (loss of pain and temp on face, facial paralysis and tinnitus). In addition, loss of pain and temp from contralateral limbs and trunk.

Answer 1

AICA syndrome or Superior cerebellar artery - aka Lateral Pontine Syndrome

Question 2

Occlusion to the medulla oblongata in the brain stem will lead to CF: sensory deficits in the trunk and extremities, on the opposite side of the infarction. Loss of pain and temp on the contralateral side of body, but ipsilateral on face. Risk for Horner’s syndrome, dysfagia, ataxia, vertigo, diplopia, and nystagmus. What is happening?

Answer 2

Lateral medullary syndrome- aka Wallenberg syndrome (PICA syndrome)

Question 3

Occlusion of branches of the Posterior Cerebral Artery can cause what?

Answer 3

Medial Midbrain Syndrome - aka Weber Syndrome

Question 4

Occlusion of the paramedian branches of the basilar artery can cause what?

Answer 4

Medial Pontine Syndrome - affects:
Corticospinal tract: contralateral spastic hemiparesis
Medial Lemniscus - contralateral loss of tactile/position/vibration sensation
Fibers of VI - medial strabismus (ipsilateral paralysis of lateral rectus muscle)

Question 5

Occlusion of either the PICA (caudal pons) or SCA (rostral pons) will result in what?

Answer 5

Lateral Pontine Syndrome:
-Ipsilateral facial nerve paralysis (facial nuc.)
-Ipsilateral loss of taste from anterior 2/3 of tongue (solitary nuc.)
-Unilateral deafness and tinnitus (cochlear nuc.)
-Nystagmus, vertigo, nausea/vomiting (Vestibular nuc.)
-Ipsilateral limb and gait ataxia (middle/inf. Cerebellar pedincles)
-Ipsilateral loss of pain and temp (Spinal trigeminal)
-Contralateral body loss of pain/temp (SpTh tract)
-Descending sympathetic tract - Ipsilateral Horner’s Sd

Question 6

Occlusion of the Anterior Spinal Artery (ASA) or the Vertebral Artery can lead to what?

Answer 6

Medial Medullary Syndrome
-Contralateral spastic hemiparesis
Medial lemniscus: Contralateral tactile and kinesthetic defects
-Hypoglossal nucleus/nerve: Tongue deviates to side of lesion

Question 7

What are the classic findings in Weber Syndrome?

Answer 7

-Contralateral spastic paralysis or hemiparesis
-CN III palsy (eye looks down and out)
-Ptosis

Question 8

What are the classic features of Wallenberg Syndrome?

Answer 8

-Contralateral loss of pain and temp sensation
-Ipsilateral loss of pain and temp on the face
-Hoarse voice, difficulty swallowing, loss of gag reflex
-Ipsilateral Horner syndrome
-Vertigo, nystagmus, nausea/vomiting
-Ipsilateral cerebellar defects

Question 9

A patient cannot abduct her left eye on lateral gaze, convergence is normal. Patient also has difficulty smiling. What part of the CNS is affected, and which CNs are lesioned?

Answer 9

Abducens nerve (CN VI), and CN VII
—> portion of the brain stem: Pons