Nerve for motor function of buccinator muscle
**Core Concept**
The buccinator muscle plays a crucial role in facial expressions and oral functions, including mastication and blowing air. Its motor function is primarily controlled by the **facial nerve (CN VII)**, which is responsible for the innervation of muscles of facial expression. The buccinator muscle receives its motor innervation from the buccal branch of the facial nerve.
**Why the Correct Answer is Right**
The **buccal branch of the facial nerve** is specifically responsible for the motor innervation of the buccinator muscle, enabling functions such as compressing the cheek against the teeth and assisting in blowing air. This nerve branch arises from the **mandibular division** of the facial nerve, which also supplies other muscles involved in facial expressions.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it does not specify the correct branch of the facial nerve responsible for the buccinator muscle's motor function.
**Option B:** Incorrect as it is not directly related to the motor function of the buccinator muscle.
**Option C:** Incorrect because, although related to the facial nerve, it is not the specific branch that innervates the buccinator muscle.
**Option D:** Incorrect as it is not associated with the motor innervation of the buccinator muscle.
**Clinical Pearl / High-Yield Fact**
Remembering that the **buccal branch of the facial nerve** controls the buccinator muscle is crucial for understanding facial paralysis and its effects on oral functions. Damage to this branch can lead to weakness in blowing air or whistling.
**Correct Answer:** Correct Answer: B. Facial Nerve.