Which nerve provides motor innervation to all intrinsic laryngeal muscles except the cricothyroid?

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The key idea here is how motor control is distributed to the muscles that tune and move the vocal cords. The intrinsic laryngeal muscles, which adjust tension and position of the vocal folds, are mainly under the motor control of the recurrent laryngeal nerve, a branch of the vagus. This nerve supplies most intrinsic muscles, including the thyroarytenoid, lateral cricoarytenoid, posterior cricoarytenoid, interarytenoids, and the vocalis, enabling opening, closing, and fine-tuning of the vocal cords.

The cricothyroid muscle is the exception; it lengthens and tenses the vocal cords and is innervated by the external branch of the superior laryngeal nerve. Meanwhile, the internal branch of the superior laryngeal nerve provides sensory innervation above the vocal cords, not motor innervation. The glossopharyngeal nerve doesn’t supply the intrinsic laryngeal muscles.

So, the nerve that provides motor innervation to all intrinsic laryngeal muscles except the cricothyroid is the recurrent laryngeal nerve.