The oblique part of cricothyroid is the posterior and larger component, acting on the inferior thyroid horn. It produces the rotation that elongates the vocal folds for high-pitched voice production.
| Origin | Lateral surface of the cricoid cartilage |
|---|---|
| Insertion | Posterior lamina and inferior horn of the thyroid cartilage |
| Nerve Supply | External branch of the superior laryngeal nerve (SLN — branch of CN X) |
| Blood Supply | Superior thyroid artery |
| Actions | Elongates and tenses the vocal folds — raises vocal pitch; The oblique part acts on the inferior thyroid horn producing a rotational movement |
|---|
The external branch of the superior laryngeal nerve innervates cricothyroid — its injury during thyroidectomy (close to the superior thyroid artery ligation) produces loss of high-pitch voice and easy voice fatigue. Professional singers are most affected. The Cernea classification describes the SLN external branch position relative to the superior thyroid artery.
Not directly palpable — function assessed by voice quality (high-pitch testing).
External SLN injury during thyroidectomy producing loss of high-pitch voice and upper register limitation, particularly devastating in professional singers.
