International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which cranial nerve is responsible for the motor function of the mouth and sensory function of the tongue during sucking?

1. Trigeminal (V)

2. Hypoglossal (XII)

3. Facial (VII)

4. Glossopharyngeal (IX)

The correct answer is: Facial (VII)

The cranial nerve primarily responsible for the motor function of the mouth and the sensory function of the tongue during sucking is the facial nerve, also known as cranial nerve VII. This nerve is crucial for the movement of facial muscles, including those responsible for lip closure, which is essential during the sucking process. Additionally, it plays a role in the sensory perception related to taste from the anterior two-thirds of the tongue, contributing to the overall experience of feeding. In the context of sucking, proper lip closure and the ability to create a seal around the breast or bottle are vital. The facial nerve innervates the orbicularis oris muscle, allowing for these movements which facilitate effective sucking. Furthermore, the sensory input from the facial nerve can help stimulate sucking reflexes, as the infant interacts with the breast or nipple. While other cranial nerves mentioned have important roles, such as the trigeminal nerve for general sensation and mastication, and the glossopharyngeal nerve for taste and some sensory functions of the tongue, they do not primarily govern the motor functions of the mouth in the context of sucking. The hypoglossal nerve, while important for tongue movements, does not directly contribute to the overall motor function of the mouth. Thus