**Question:** Following is true about safety muscle of tongue -

A. The lingual nerve supplies the anterior two-thirds of the tongue only.
B. The lingual nerve supplies the posterior two-thirds of the tongue only.
C. The lingual nerve supplies the entire tongue.
D. The lingual nerve supplies the floor of the mouth as well as the tongue.

**Core Concept:**
The lingual nerve (Cranial nerve VII) is a branch of the facial nerve that plays a crucial role in sensory, motor, and special sensory functions. In the context of the tongue, it supplies motor neurons to the intrinsic muscles of the tongue, allowing for its movement. Additionally, it provides sensory neurons for taste sensation and special sensory neurons for pain and temperature perception in the tongue and floor of the mouth.

**Why the Correct Answer is Right:**
The correct answer (D) states that the lingual nerve supplies the floor of the mouth as well as the entire tongue. This is accurate because the lingual nerve not only innervates the tongue muscles, but also carries sensory information from the tongue and floor of the mouth, including taste sensation, pain, and temperature perception.

**Why Each Wrong Option is Incorrect:**
A and B are incorrect because they specify that the lingual nerve supplies only the anterior or posterior thirds of the tongue, respectively. However, the lingual nerve supplies the entire tongue.

C is incorrect because it states that the lingual nerve supplies the entire tongue, including extrinsic muscles. The lingual nerve only supplies the intrinsic muscles of the tongue, not its extrinsic counterparts.

**Clinical Pearl:**
The lingual nerve plays a vital role in sensory, motor, and special sensory functions, making it essential for proper tongue function and sensation. A thorough understanding of the innervation of the tongue and its surrounding structures can aid in diagnosing and treating patients with tongue or oral sensory deficits.