**Question:** In a patient of carcinoma tongue, the infiltration of which muscle causes ankyloglossia?

**Core Concept:** Ankyloglossia (also known as tongue-tie) is a condition where the lingual frenulum, a thin band of tissue connecting the base of the tongue to the floor of the mouth, is short and tight. This can limit the tongue's mobility and may cause difficulties in speech, feeding, and oral hygiene.

**Why the Correct Answer is Right:** Infiltration of the lingual nerve and its branches can lead to the involvement of lingual muscles, including the lingualis muscle. The lingualis muscle is responsible for upward and medial movements of the tongue. When infiltrated, it can result in partial or complete loss of tongue mobility, which is characteristic of ankyloglossia.

**Why Each Wrong Option is Incorrect:**

A. **Lingualis muscle:** This muscle is involved in the correct answer, as explained above.
B. **Genioglossus muscle:** This muscle is responsible for downward and lateral movements of the tongue and is not directly involved in ankyloglossia.
C. **Hyoglossus muscle:** This muscle is involved in the protrusion of the tongue and is not directly related to ankyloglossia.
D. **Masseter muscle:** This muscle is responsible for mastication (chewing) and jaw movements and is not involved in ankyloglossia.

**Clinical Pearl:** Ankyloglossia should be considered in patients with difficulty in tongue movement, especially during feeding or speech. In such cases, a thorough oral examination is essential to identify the short lingual frenulum as the primary cause. Treatment may involve frenulectomy, a surgical procedure to release the frenulum, improving tongue mobility and alleviating symptoms.