The thyrohyoid membrane is a broad fibroelastic sheet connecting the superior border of the thyroid cartilage to the posterior surface of the body and greater horns of the hyoid bone, forming the anterior wall of the pre-epiglottic space. The internal branch of the superior laryngeal nerve and the superior laryngeal artery pierce the membrane laterally to enter the laryngeal interior. The median and lateral thyrohyoid ligaments are thickened portions of the membrane.
Connects the thyroid cartilage to the hyoid bone, allows the larynx to elevate during swallowing as the thyrohyoid muscles contract, and defines the anterior boundary of the pre-epiglottic space between the membrane and the epiglottis.
The thyrohyoid membrane is pierced during transcervical endoscopic laryngeal procedures and direct laryngoscopy approaches. The internal superior laryngeal nerve crossing through the lateral membrane is at risk in supraglottic laryngectomy and near-total laryngectomy. Compression of the internal laryngeal nerve at the membrane level by osteochondroma of the greater cornu of the hyoid (Thost syndrome) produces irritative laryngeal symptoms. The pre-epiglottic space through which the membrane passes is a route for transglottic tumour spread beyond the larynx.
The internal branch of the superior laryngeal nerve piercing the thyrohyoid membrane is at risk during supraglottic laryngectomy and thyroid surgery extending to the upper thyroid pole, causing ipsilateral supraglottic sensory loss with increased aspiration risk from impaired laryngeal reflexes.
Supraglottic and transglottic laryngeal cancers extend anteriorly through the pre-epiglottic space bounded by the thyrohyoid membrane, enabling tumour to exit the larynx into the neck soft tissues, a pathway requiring total laryngectomy rather than supraglottic resection.
