National Board Dental Hygiene Examination (NBDHE) Dental Hygienist Practice Test

What nerve supplies the intrinsic muscles of the tongue?

1. Trochlear

2. Trigeminal

3. Glossopharyngeal

4. Hypoglossal

The correct answer is: Hypoglossal

The intrinsic muscles of the tongue are primarily responsible for altering the shape and size of the tongue, enabling functions such as speech and swallowing. The hypoglossal nerve is the cranial nerve that innervates these intrinsic muscles. The hypoglossal nerve, also known as cranial nerve XII, specifically controls all the intrinsic muscles of the tongue as well as most of the extrinsic muscles, facilitating various movements. This nerve emerges from the medulla oblongata and innervates the tongue with motor fibers, allowing for precise movements. In contrast, other nerves listed serve different functions: the trochlear nerve is involved in eye movement, the trigeminal nerve primarily provides sensation to the face and motor functions for mastication, and the glossopharyngeal nerve is mainly responsible for the sensory and some motor functions of the pharynx and posterior part of the tongue. Therefore, the hypoglossal nerve is uniquely suited to facilitate the motor control of the intrinsic tongue muscles, making it the correct choice for this question.