Head and neck muscles (chewing, facial, and throat muscles)

Straight part of cricothyroid

Musculus cricothyroideus, pars recta

Origin

Front side of the arch of the cricoid cartilage

Insertion

Lower border and inferior horn of the thyroid cartilage

Function

Tilts the thyroid cartilage forward relative to the cricoid, lengthening and tensing the vocal folds; raises the pitch of the voice

Innervation

External branch of the superior laryngeal nerve (vagus nerve, CN X)

Movement & chain

The only intrinsic laryngeal muscle not innervated by the recurrent laryngeal nerve; crucial for pitch adjustment during singing and speaking.

Palpation

The cricothyroid space, which this muscle spans, is felt as a small dip just below the Adam's apple (laryngeal prominence).

Clinical

Damage to the superior laryngeal nerve causes a hoarse, tired voice with reduced range in high notes, while the airway remains intact.

Segmental innervation

Motor via the superior laryngeal nerve (vagus nerve, CN X); no spinal segment.

In clinical practice

Marks the cricothyroid membrane, the puncture site for an emergency cricothyroidotomy in an unmanageable airway.

Region in the model

Head and neck muscles (chewing, facial, and throat muscles)