Unit
- Cartilaginous framework: The laryngeal skeleton comprises nine cartilages, with the thyroid, cricoid, and epiglottis being the most prominent. These structures provide rigidity and serve as attachment points for muscles and ligaments that control tension and position.
- Thyroid cartilage: The largest laryngeal cartilage forms the anterior prominence known as the Adam's apple. Its laminae meet at the midline and serve as an anchor for the vocal ligament and extrinsic muscles that elevate the larynx during swallowing.
- Cricoid cartilage: This signet-ring shaped cartilage sits inferior to the thyroid and is the only complete circular cartilage in the airway. It provides structural support and articulates with the thyroid and arytenoid cartilages through synovial joints.
- Arytenoid cartilages: Paired pyramid-shaped cartilages sit atop the posterior cricoid lamina. Their muscular attachments allow rotation and sliding, which adduct or abduct the vocal folds to modulate airflow and phonation.
- Epiglottis: A leaf-shaped elastic cartilage that projects upward behind the hyoid bone. During swallowing, it folds backward to cover the laryngeal inlet, directing food into the esophagus and protecting the lower airway.
- Intrinsic muscles: These muscles connect laryngeal cartilages and adjust vocal fold tension and position. Key groups include the thyroarytenoid, lateral cricoarytenoid, and posterior cricoarytenoid, each responsible for specific movements such as adduction or elongation.
- Extrinsic muscles: Muscles attaching the larynx to surrounding structures (hyoid bone, sternum, pharynx) elevate or depress the larynx during swallowing, phonation, and respiration. The suprahyoid group elevates; the infrahyoid group depresses.
- Mucosal lining: The laryngeal mucosa transitions from respiratory epithelium in the subglottis to stratified squamous epithelium on the vocal folds. This differentiation influences susceptibility to irritation, infection, and neoplastic changes.
- Innervation: The recurrent laryngeal nerve supplies all intrinsic muscles except cricothyroid, which is innervated by the external branch of the superior laryngeal nerve. Sensory innervation divides at the vocal folds, with the internal branch of the superior laryngeal nerve providing sensation above them.
- Vascular supply: The larynx receives blood from the superior and inferior laryngeal arteries, branches of the superior thyroid and inferior thyroid arteries respectively. Venous drainage follows the corresponding veins into the internal jugular and brachiocephalic veins, which is relevant for understanding metastatic spread.
- Laryngeal cavities: The laryngeal cavity is divided into three regions: supraglottis (above the vocal folds), glottis (vocal folds and rima glottidis), and subglottis (below the vocal folds down to the cricoid cartilage). Each subsite has distinct anatomical features and clinical implications for pathology and management.
Scope of Practice
Role: Healthcare Manager in Otolaryngology Clinic
Within scope:
- Reviewing anatomical diagrams to understand patient reports and imaging summaries.
- Coordinating referrals based on laryngeal subsite involvement (supraglottis, glottis, subglottis).
- Educating patients on basic laryngeal anatomy during pre-procedure counseling.
Outside scope:
- Performing laryngeal examinations or interpreting direct laryngoscopy findings.
- Diagnosing structural abnormalities from imaging studies.
- Prescribing treatments based on anatomical variations.
Quick Revision
- The laryngeal skeleton consists of nine cartilages including thyroid, cricoid, arytenoids, and epiglottis.
- Intrinsic muscles control vocal fold movement; extrinsic muscles elevate or depress the larynx.
- Mucosal type differs by region, affecting disease patterns.
- Healthcare managers should understand anatomy for informed care coordination.