Question

Loss of pain and temperature sensation on the ipsilateral face and contralateral body is due to thrombosis in the:

• A. Posterior inferior cerebellar artery (PICA)
• B. Posterior cerebellar artery
• C. Superior cerebellar artery
• D. None of the above

Hint:

Crossed face and body pain or temperature loss names a classic brainstem syndrome with a famous artery.

Answer 1

The Correct Option is A

Step 1: Recognise the syndrome. Crossed sensory loss, pain and temperature lost on the same side of the face but the opposite side of the body, is the hallmark of lateral medullary (Wallenberg) syndrome.
Step 2: Explain the crossed pattern. The spinal trigeminal nucleus serves the ipsilateral face, while the already crossed spinothalamic tract carries pain and temperature from the contralateral body. A lateral medullary lesion hits both, giving the crossed picture.
Step 3: Identify the vessel. The syndrome results most often from vertebral artery occlusion, and the named artery classically associated with it is the posterior inferior cerebellar artery (PICA).
Step 4: Other features. Wallenberg syndrome also causes vertigo, dysphagia, dysarthria, hoarseness, ataxia, and ipsilateral Horner syndrome. So the answer is PICA. Ref: Adams and Victor's Principles of Neurology, 11e.