Question 3
A lacunar stroke in either the internal capsule or the base (ventral-medial region) of the pons could produce a pure motor syndrome: weakness or paralysis of the arm or leg on one side with no other findings.
Question a. In each case, on which side does paralysis occur?
a. same side as the lesion
b. opposite side from the lesion
Question b. In each case, the stroke is produced by occlusion of slender vessels that penetrate deeply into the brain. Branches of MCA supply the internal capsule; branches of what major vessel supply the ventral-medial pons?
Question c. Lacunar strokes also occur commonly in the thalamus, where they can produce a pure hemisensory deficit. Branches of what major vessel supply most of the thalamus?
Answer to Question 3
Correct Answer to Question a:
b. opposite side from the lesion
Additional Information:
Paralysis is on the opposite side from the lesion. (Axons of the corticospinal tracts cross the midline at the junction between medulla and cervical spinal cord.)
Correct Answer to Question b:
The basilar artery supplies the ventral-medial pons.
Correct Answer to Question c:
PCA branches supply most of the thalamus, especially the part containing the somatosensory nuclei.