During parotidectomy, the facial nerve (CN VII) is most reliably identified at the tympanomastoid fissure between the pointer landmark. The 'pointer' (tragal pointer) indicates that the facial nerve trunk lies approximately how deep to the pointer tip?
- A 5–10 mm medial and inferior to the tip of the tragal pointer (cartilaginous pointer) ✓
- B 1 mm deep and inferior
- C Directly posterior to the mastoid tip
- D At the level of the stylomastoid foramen, 2 cm medial to the anterior wall of the external auditory canal
Correct answer: A. 5–10 mm medial and inferior to the tip of the tragal pointer (cartilaginous pointer)
Explanation
The 'tragal pointer' is the medial aspect of the tragal cartilage — a reliable surgical landmark. The facial nerve trunk exits the stylomastoid foramen and lies approximately 1 cm (range 5–10 mm) deep and inferior to the tip of the tragal pointer, just anterior to the digastric ridge on the mastoid. Other landmarks include the styloid process (nerve lies anterolateral) and the tympanomastoid fissure. These landmarks reduce the risk of inadvertent nerve injury during parotidectomy.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.