## **Core Concept**
The submandibular gland is located in the neck and is surrounded by several important cranial nerves. The surgical removal of this gland, known as a submandibulectomy, requires careful consideration of the nerves in the vicinity to avoid injury.

## **Why the Correct Answer is Right**
The correct answer, **D. Facial nerve (CN VII)**, is accurate because the facial nerve is intimately associated with the submandibular gland. The facial nerve, or cranial nerve VII, emerges from the stylomastoid foramen and courses through the parotid gland before dividing into its terminal branches. The marginal mandibular branch of the facial nerve is particularly at risk during submandibular gland surgery because it runs close to the gland and can be damaged during dissection.

## **Why Each Wrong Option is Incorrect**
- **Option A:** The **Trigeminal nerve (CN V)** is not directly at risk during submandibular gland removal. While it is a cranial nerve, its branches are primarily involved in sensory innervation of the face and motor innervation of the muscles of mastication, and it is not in close proximity to the submandibular gland.
- **Option B:** The **Glossopharyngeal nerve (CN IX)** is involved in swallowing and taste sensation from the posterior one-third of the tongue. It does have some proximity but is less directly involved and at risk compared to CN VII during this procedure.
- **Option C:** The **Hypoglossal nerve (CN XII)**, which controls tongue movements, does traverse the surgical field for submandibular gland removal and is indeed at risk. However, the question likely seeks the most directly and frequently implicated nerve.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that the **marginal mandibular branch of the facial nerve (CN VII)** is particularly vulnerable during submandibular gland surgery. Surgeons often identify and carefully dissect this nerve to preserve its function. A useful tip is that this branch usually lies deep to the platysma but superficial to the anterior part of the submandibular gland.

## **Correct Answer: D. Facial nerve.**