Regarding the anatomy and course of the facial nerve (CN VII), all of the following statements are correct EXCEPT:

Explanation

## Facial Nerve Anatomy and Branches ### Correct Statements (Options 0, 1, 2) **Key Point:** The facial nerve (CN VII) is the seventh cranial nerve with complex motor, sensory, and parasympathetic functions. | Feature | Details | |---------|----------| | **Exit point** | Stylomastoid foramen (exits skull here) | | **Chorda tympani** | Preganglionic parasympathetic to submandibular & sublingual glands; also carries taste from anterior 2/3 tongue | | **Greater petrosal nerve** | Preganglionic parasympathetic to lacrimal gland; arises within petrous bone | ### Why Option 3 is INCORRECT **High-Yield:** The muscles of mastication (masseter, temporalis, medial pterygoid, lateral pterygoid) are innervated by the **trigeminal nerve (CN V3)**, NOT the facial nerve. **Clinical Pearl:** The facial nerve innervates muscles of *facial expression* (orbicularis oculi, orbicularis oris, buccinator, platysma, etc.), not mastication. The buccal branch of CN VII innervates the buccinator muscle (facial expression), not the muscles of mastication. **Mnemonic:** **FACIAL = Face muscles** (CN VII); **TRIGEMINAL = Mastication** (CN V3). ### Summary Table: CN V vs CN VII Motor Innervation | Nerve | Motor Innervation | |-------|-------------------| | **CN V3 (Trigeminal)** | Muscles of mastication, tensor tympani, mylohyoid, anterior belly of digastric, tensor veli palatini | | **CN VII (Facial)** | Muscles of facial expression, stapedius, posterior belly of digastric, stylohyoid, platysma | [cite:Clinically Oriented Anatomy 8e Ch 8]