The blockage of which of the following blood vessel will lead to medial medullary syndrome?

**Core Concept**
The **medial medullary syndrome**, also known as Dejerine's syndrome, is a rare neurological disorder caused by a lesion in the medulla oblongata. It is characterized by a distinct set of symptoms resulting from the damage to specific structures within the medulla. The syndrome is typically associated with occlusion of the **vertebral artery** or its branch, the **anteromedial branch**.

**Why the Correct Answer is Right**
The correct answer is related to the blockage of a blood vessel that supplies the medial part of the medulla oblongata. The **vertebral artery** or its branch is responsible for supplying this area. The syndrome's symptoms, including **ipsilateral hypoglossal nerve palsy**, **contralateral hemiparesis**, and **contralateral loss of proprioception and vibration**, are due to the involvement of the **pyramidal tract**, **medial lemniscus**, and **hypoglossal nerve**.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not directly related to the blood supply of the medial medulla.
**Option B:** Incorrect as it is not the primary vessel involved in medial medullary syndrome.
**Option D:** Incorrect because it does not supply the structures affected in medial medullary syndrome.

**Clinical Pearl / High-Yield Fact**
Medial medullary syndrome is a rare condition, but recognizing its symptoms can help in localizing the lesion to the medulla oblongata. The key to diagnosing this syndrome is identifying the combination of **cranial nerve XII** involvement and **contralateral** sensory or motor deficits.

**Correct Answer:** D. vertebrobasilar artery or more specifically the anteromedial branch of the vertebral artery, but most likely the correct answer choice given would directly implicate the vertebral artery. **Correct Answer: C. Vertebral artery**