Which nerve is derived from the cervical plexus and contributes to external ear innervation?

Which nerve is derived from the cervical plexus and contributes to external ear innervation?

• A. Lesser auricular nerve
• B. Great auricular nerve
• C. Posterior auricular nerve
• D. Auriculotemporal nerve

Answer: (B)

The main idea is that the cervical plexus provides several cutaneous nerves to the head and neck, and the great auricular nerve is the primary branch from this plexus (C2–C3) that supplies the external ear. It travels across the sternocleidomastoid to the parotid region and auricle, giving sensation to most of the skin of the external ear and its surrounding area. That makes it the best choice for a nerve derived from the cervical plexus contributing to external ear innervation. The other nerves don’t fit as well: the posterior auricular nerve comes from the facial nerve, not the cervical plexus; the auriculotemporal nerve comes from the mandibular division of the trigeminal nerve; and while the lesser auricular nerve also comes from the cervical plexus, it supplies a smaller portion of the ear, whereas the great auricular nerve is the principal cervical-plexus contributor to the ear.

The main idea is that the cervical plexus provides several cutaneous nerves to the head and neck, and the great auricular nerve is the primary branch from this plexus (C2–C3) that supplies the external ear. It travels across the sternocleidomastoid to the parotid region and auricle, giving sensation to most of the skin of the external ear and its surrounding area. That makes it the best choice for a nerve derived from the cervical plexus contributing to external ear innervation.

The other nerves don’t fit as well: the posterior auricular nerve comes from the facial nerve, not the cervical plexus; the auriculotemporal nerve comes from the mandibular division of the trigeminal nerve; and while the lesser auricular nerve also comes from the cervical plexus, it supplies a smaller portion of the ear, whereas the great auricular nerve is the principal cervical-plexus contributor to the ear.