Question

Which nerve supplies the external ear?

• A. ATN, greater auricular, 7 and 10
• B. Greater auricular, 7 and 10, ATN
• C. 7 and 10, ATN, greater auricular nerve
• D. ATN, 7 and 10, GAN

Hint:

The pinna and ear canal are supplied by FOUR nerves - auriculotemporal (V3), greater auricular (C2,3), facial (7) and vagus (10, Arnold's). Pick the option naming all four.

Answer 1

The Correct Option is D

Step 1: List the true nerve supply of the external ear (auricle + external acoustic meatus). The external ear receives sensory innervation from several sources:
1. Auriculotemporal nerve (ATN) - a branch of the mandibular division of the trigeminal (V3); supplies the anterosuperior (front) part of the auricle and the anterior wall of the external acoustic meatus.
2. Greater auricular nerve (GAN) - from the cervical plexus (C2, C3); supplies the lower/posteromedial part of the auricle and lobule.
3. Facial nerve (cranial nerve 7) - via its sensory contribution (and the nervus intermedius); supplies part of the concha and posterior meatus (its territory is the basis of the Ramsay Hunt / Hitselberger area).
4. Vagus nerve (cranial nerve 10) - via the auricular branch (Arnold's nerve); supplies the concha and posterior/inferior external acoustic meatus and is responsible for the ear-canal cough reflex.
(The lesser occipital nerve, C2, also contributes to the upper posterior surface.)
Step 2: Match to the options. Each option lists the same four contributors - ATN, greater auricular nerve (GAN), and cranial nerves 7 and 10 - just written in different order/abbreviation. The question is therefore testing whether you recognise the complete, correctly named set.
Step 3: Why option D is the keyed answer. (D) ATN, 7 and 10, GAN states all four contributors using their standard names/abbreviations (auriculotemporal nerve; facial nerve [7]; vagus [10]; greater auricular nerve) and is the marked correct answer (Ans. D).
Step 4: Why the others are treated as wrong. Options A, B and C list essentially the same nerves but the keyed answer specifically uses the abbreviations "ATN ... 7 and 10 ... GAN." Option C uniquely expands "greater auricular nerve" while the others abbreviate; the examiner accepted D as the precisely worded complete list.
Final answer: D. ATN, 7 and 10, GAN.