CN XI SCM Trapezius — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

EasyAnatomyCN XI SCM TrapeziusFRCA Primary

The accessory nerve (CN XI) has a spinal root that innervates:

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Sternocleidomastoid and trapezius

The spinal root of CN XI arises from the anterior horn cells of C1-C5 and ascends through the foramen magnum to exit via the jugular foramen. It innervates sternocleidomastoid (ipsilateral head rotation) and trapezius (shoulder elevation/shrug). Accessory nerve injury causes: inability to shrug the shoulder and weakness of head turning.

Reference: RCoA 2021 Primary FRCA Curriculum