2 Relevant Anatomy
The larynx is comprised of the epiglottis, thyroid, arytenoids, and cricoid cartilages. The reversed signet ring cricoid is attached anteriorly to the thyroid cartilage by the cricothyroid membrane and cricothyroid muscle. This muscle arises from the anterior cricoid and travels superiorly and posterolaterally to attach to the lateral surface of the thyroid cartilage and rotates the thyroid anteriorly lengthening the vocal cords. Injury to the cricoid or thyroid cartilage during cricothyrotomy or tracheotomy could affect voice and airway patency. The innominate artery or brachiocephalic trunk crosses the anterior trachea at the thoracic inlet and is vulnerable to injury during and after tracheotomy. The trachea has cartilaginous rings anterolaterally and is membranous posteriorly and between these rings. The thyroid gland isthmus crosses the trachea anteriorly in the area of the second and third tracheal ring. Paratracheal structures of concern include the carotid arteries, jugular veins, thyroid gland, and recurrent laryngeal nerves. Surgical access to the brachymorphic neck is limited and difﬁcult; a thorough knowledge of these structures is essential to avoid damaging them during tracheotomy.