Superficial incision on posterior triangle of neck lead to
**Core Concept**
The posterior triangle of the neck is an anatomical region bounded by the sternocleidomastoid muscle ( SCM ) anteriorly, the trapezius muscle posteriorly, and the base of the skull superiorly. The superficial structures in this region include the platysma muscle, the external jugular vein, and the accessory nerve ( CN XI ).
**Why the Correct Answer is Right**
A superficial incision in the posterior triangle of the neck can lead to injury of the accessory nerve ( CN XI ). The accessory nerve is a motor nerve that supplies the sternocleidomastoid muscle ( SCM ) and the trapezius muscle. It passes through the posterior triangle, lying deep to the platysma muscle and superficial to the external jugular vein. Injury to the accessory nerve can result in weakness or paralysis of the SCM and trapezius muscles, leading to difficulties with shoulder movements and neck rotation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the external jugular vein is a superficial structure in the posterior triangle and is not commonly injured by a superficial incision.
**Option B:** This option is incorrect as the subclavian artery is located deeper in the neck and is not directly related to a superficial incision in the posterior triangle.
**Option C:** This option is incorrect as the hypoglossal nerve ( CN XII ) is not located in the posterior triangle and is not at risk with a superficial incision in this region.
**Clinical Pearl / High-Yield Fact**
The accessory nerve ( CN XI ) is a high-yield fact for the posterior triangle of the neck, as injury to this nerve can result in significant morbidity and require surgical repair.
**Correct Answer:** C. Injury to the accessory nerve ( CN XI ).