Oblique Part of the Cricothyroid Muscle, Gross Anatomy

Description

Anterior laryngeal anatomy is presented with emphasis on the oblique part of the cricothyroid muscle (musculus cricothyroideus, pars obliqua) on a male specimen/model. Its fibers arise from the anterolateral arch of the cricoid cartilage and pass superiorly and laterally to insert along the inferior margin and inferior horn (cornu inferius) of the thyroid cartilage, lying superficial to the cricothyroid membrane. The thyroid cartilage forms the superior shield, the cricoid cartilage sits inferiorly as a complete ring, and the proximal tracheal rings continue caudally. Small but telling landmarks are typically appreciable. The epiglottis projects superiorly, and paired intrinsic laryngeal muscle masses such as thyroarytenoid may be suggested deeper, posterior to the thyroid laminae. Orientation of the pars obliqua matters because it is the only intrinsic laryngeal muscle on the external surface of the larynx and the primary tensor of the vocal folds. Contraction rocks the thyroid cartilage anteriorly on the cricoid at the cricothyroid joints, lengthening the vocal ligament and raising fundamental frequency, a concept central to phonation teaching and to understanding superior laryngeal nerve (external branch) injury. This is the nerve at risk during superior thyroid pole ligation in thyroidectomy, where postoperative loss of high pitch and vocal fatigue can be traced back to impaired cricothyroid function. Use this asset for gross anatomy and head and neck courses, voice and swallowing modules in speech-language pathology curricula, and surgical atlases covering thyroidectomy exposure, cricothyrotomy landmarks, and laryngeal framework mechanics. It also fits ENT clinic education materials explaining pitch control and external branch superior laryngeal nerve palsy. Anatomical accuracy verified by SciePro's Medical Advisory Board.