A 60-year-old man presents with complaint of inability to swallow and hoarseness of his voice for the last two hours. His wife tells you about multiple episodes of vomiting and dizziness her husband experienced while moving about the house.His vitals are stable. On clinical examination, you find that he has an ataxic gait towards the left along with miosis and ptosis on the same side. A detailed CNS examination reveals decreased pain, temperature sensations on the right side of his body coupled with a right-sided detion of his uvula. Which of the following aeries has most likely been occluded?

## **Core Concept**
The patient's symptoms suggest a lateral medullary syndrome, also known as Wallenberg's syndrome, which occurs due to a lesion in the lateral part of the medulla oblongata. This syndrome is typically caused by the occlusion of a specific artery that supplies the lateral medulla.

## **Why the Correct Answer is Right**
The correct answer, **. Posterior Inferior Cerebellar Artery (PICA) or more specifically in this context, the Vertebral Artery**, is implicated because the occlusion leads to a Wallenberg's syndrome. This syndrome is characterized by:
- Ataxic gait due to involvement of the inferior cerebellar peduncle or cerebellum itself.
- Miosis and ptosis on one side due to disruption of the descending sympathetic fibers.
- Decreased pain and temperature sensation on the contralateral side of the body due to the involvement of the lateral medullary (or spinal) tract.
- Ipsilateral deviation of the uvula due to involvement of the nucleus ambiguus or its fibers.

## **Why Each Wrong Option is Incorrect**
- **Option A:** The **Anterior Cerebral Artery** primarily supplies the medial surface of the brain, including parts of the frontal and parietal lobes. Occlusion of this artery would not result in the symptoms described.
- **Option B:** The **Anterior Inferior Cerebellar Artery (AICA)** supplies the anterior part of the inferior surface of the cerebellum and the pons. While its occlusion can cause cerebellar symptoms, it does not typically cause the full spectrum of Wallenberg's syndrome.
- **Option D:** The **Basilar Artery** supplies the brainstem (including the pons and midbrain) and the posterior inferior parts of the cerebellum. While occlusion of the basilar artery can cause brainstem and cerebellar symptoms, the specific constellation of symptoms described is more localized to the lateral medulla.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Wallenberg's syndrome, caused by occlusion of the **Vertebral Artery** or **PICA**, presents with a classic triad of symptoms: difficulty swallowing (dysphagia), hoarseness (dysarthria), and ataxia, along with the specific pattern of sensory deficits and other signs like miosis and ptosis.

## **Correct Answer:** . Vertebral Artery.

✓ Correct Answer: C. Posterior Inferior Cerebellar Aery