Okay, let's tackle this question. The user is asking which structure is not present on the medial surface of the submandibular gland. First, I need to recall the anatomy of the submandibular gland. The submandibular gland is a major salivary gland located in the submandibular triangle of the neck.

The medial surface of the gland is adjacent to several structures. The facial artery and vein run along the medial side, as does the lingual nerve. The hypoglossal nerve is also nearby. However, the submandibular duct (Wharton's duct) typically exits the anterior part of the gland, not the medial surface. The medial surface is more about arteries, veins, and nerves.

Wait, but the question is about what's not present. The options aren't provided, but based on common anatomy questions, the submandibular duct is usually on the anterior surface, not the medial. So if an option includes the submandibular duct, that would be the correct answer here. Other structures like the lingual artery or vein might be present. Alternatively, the facial artery and vein are on the medial surface. So if an option lists the submandibular duct as being on the medial surface, that's the wrong one.

I should make sure about the exact anatomical relations. The medial surface of the submandibular gland is in contact with the hyoglossus muscle, the hypoglossal nerve, and the lingual nerve. The duct (Wharton's) exits the anterior border of the gland. Therefore, the submandibular duct is not on the medial surface. So if the options include the submandibular duct as being present on the medial surface, that's the incorrect one. The correct answer would be the option that lists the duct as present there.

**Core Concept**
The submandibular gland's medial surface is anatomically distinct, containing specific neurovascular structures but lacking the submandibular duct (Wharton’s duct). Key structures include the lingual nerve, hypoglossal nerve, and facial artery/vein.

**Why the Correct Answer is Right**
The submandibular duct (Wharton’s duct) originates from the anterior aspect of the gland, not the medial surface. It courses anteriorly to open into the sublingual papilla. The medial surface is instead marked by the lingual artery, hypoglossal nerve, and the mylohyoid muscle. Structures like the facial artery and vein, lingual nerve, and hypoglossal nerve lie medial to the gland, making them consistent with this region.

**Why Each Wrong Option is Incorrect**
**Option A:** *(Example: Lingual nerve)* – The lingual nerve lies medial to the submandibular gland and is present on its medial surface.
**Option B:** *(Example: Facial artery)* – The facial artery/vein runs along the medial surface of the gland.
**Option C:** *(Example: Hypoglossal nerve)* – The hypoglossal nerve is a landmark on the medial surface of the gland.
**Option D:** *(Example: Mylohyoid muscle)* – The mylohyoid muscle forms the floor of the submandibular gland’s medial surface.

**Clinical Pearl / High-Yield Fact**
Remember the

✓ Correct Answer: C. Facial vein