During thyroid surgery, which nerve is at risk that controls the cricothyroid muscle?

The cricothyroid muscle is primarily controlled by the external branch of the superior laryngeal nerve. This muscle plays a crucial role in modulating pitch by tensing the vocal cords. During thyroid surgery, the external branch of the superior laryngeal nerve is at significant risk of injury due to its close anatomical proximity to the thyroid gland. If this nerve is damaged, it can result in a decreased ability to produce high-pitched sounds, leading to voice changes or hoarseness.

The anatomy of the laryngeal innervation is important for understanding why this specific nerve is at risk during surgical procedures on or near the thyroid gland. In contrast, the other nerves mentioned in the options have different functions and anatomical locations that do not directly involve the control of the cricothyroid muscle, making them less relevant in the context of this surgical risk.