Vertical Part of the Cricothyroid Muscle

Description

Running along the anterolateral larynx, the vertical part (pars recta) of the cricothyroid muscle is shown as a dense, longitudinal bundle spanning from the anterolateral arch of the cricoid cartilage inferiorly to the inferior margin and inferior horn region of the thyroid cartilage superiorly. Its fibers lie superficial to the cricothyroid joint and sit anterior to the more posterior intrinsic laryngeal muscles, with the thyroid cartilage positioned superior and slightly anterior to the complete ring of the cricoid. Adjacent landmarks commonly included in this lateral laryngeal model include the thyroid lamina, the cricoid arch, the superiorly placed epiglottis, and the proximal tracheal rings inferior to the cricoid. Fiber direction is the tell. Because the cricothyroid is the primary tensor of the vocal folds, this focused view is the clearest way to teach how anterior tilting of the thyroid cartilage at the cricothyroid joint lengthens the vocal ligament and raises phonation frequency. Clinically, it anchors discussion of superior laryngeal nerve injury: denervation of the external branch produces reduced pitch range and vocal fatigue, a common postoperative complaint after thyroidectomy when the nerve is at risk near the superior thyroid vessels. The relationship between the muscle belly and the cricothyroid membrane also supports airway teaching, since cricothyrotomy traverses this membrane immediately superior to the cricoid arch. Speech-language pathology modules on voice, gross anatomy lab practicals on intrinsic laryngeal muscles, and ENT operative anatomy lectures all benefit from this isolated emphasis on the pars recta in lateral orientation. It also fits cleanly into atlas plates or journal figures discussing pitch control, superior laryngeal nerve anatomy, or emergency front-of-neck access. Anatomical accuracy verified by SciePro's Medical Advisory Board.