Anatomy & Histology · patient case with 1 question
Sudden one-sided facial weakness
Patient: Female, 41 years old
Chief Complaint: “The right side of my face dropped overnight.”
Background: Woke with the weakness. No limb weakness, no speech difficulty, no headache. Recent upper respiratory infection.
Vital Signs: BP 122/78 mmHg · HR 74 bpm · T 98.6°F
Findings: Cannot raise the right eyebrow, cannot close the right eye completely, and the right nasolabial fold is flattened. Sensation of the face is intact. Forehead involvement is present.
Question 1
Through which opening does this nerve exit the skull?
Show answer and explanation
Correct answer: C. Stylomastoid foramen
- A. The jugular foramen transmits cranial nerves IX, X and XI along with the internal jugular vein.
- B. The internal acoustic meatus is where CN VII and CN VIII ENTER the petrous temporal bone. The question asks where the nerve exits the skull, which is the stylomastoid foramen.
- C. CORRECT. The facial nerve leaves the cranial cavity through the internal acoustic meatus, travels through the facial canal within the petrous temporal bone — giving off the greater petrosal nerve, the nerve to stapedius and the chorda tympani along the way — and finally EXITS THE SKULL at the STYLOMASTOID FORAMEN, between the styloid and mastoid processes. It then enters the parotid gland and divides into its five terminal branches.
- D. The foramen ovale transmits V3, the mandibular division of the trigeminal nerve.