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The larynx, which is continuous with the laryngopharynx superiorly and trachea inferiorly, provides an open airway and acts as a switching mechanism to route air and food into the proper channels. The larynx, commonly known as the voice box, is supported by the hyoid bone, and provides the cartilaginous framework for muscle attachments and vocal folds, which vibrate to produce sound.


The hyoid bone consists of a body, two greater horns, and two lesser horns, and is the only bone that does not articulate with another bone. The hyoid bone is U-shaped and is suspended from the tips of the styloid processes of the temporal bones by the stylohyoid ligaments (Figure 28-1A and C). The hyoid bone is connected to the thyroid cartilage by the thyrohyoid membrane and supported by the suprahyoid and infrahyoid muscles and by the middle pharyngeal constrictor muscle. In addition, the hyoid bone supports the root of the tongue.

Figure 28-1:

A. Views of the cartilaginous skeleton. B. Superior view, looking down into the vocal ligament anatomy. C. Posterior view of the movements of the laryngeal cartilage joints.


The framework of the larynx is an intricate arrangement of nine cartilages connected by membranes and ligaments (Figure 28-1A–C).

  • Thyroid cartilage. Lies inferior to the hyoid bone and forms a midline elevation, called the laryngeal prominence (“Adam's apple”). The thyroid cartilage typically is larger in males than in females because the male sex hormones stimulate its growth during puberty.

    • Superior horn. Attaches to the tip of the greater horn of the hyoid bone.

    • Inferior horn. Articulates with the cricoid cartilage, forming the cricothyroid joint.

    • Thyrohyoid membrane. Stretches between the thyroid cartilage and the hyoid bone. The superior laryngeal vessels and the internal laryngeal nerve pierce the membrane en route to providing vascular supply and sensory information, respectively, to the mucosa superior to the vocal folds.

  • Cricoid cartilage. Shaped like a signet ring (the only complete ring of cartilage in the airways). The lower border marks the inferior limits of the larynx and pharynx. Provides attachments for laryngeal muscles, cartilages, and ligaments involved in opening and closing of the airway to produce sound.

    • Cricothyroid ligament. Arises inferiorly from the cricoid cartilage and inserts superiorly in thyroid cartilage and vocal processes of the arytenoid cartilages.

  • Epiglottis. A spoon-shaped structure consisting of elastic cartilage and is positioned posterior to the root of the tongue. The lower end of the epiglottis is attached to the deep surface of the thyroid cartilage.

    • Function. When only air is flowing into the larynx, the inlet to the larynx is open wide, with the free edge of the epiglottis projecting superiorly and anteriorly. During swallowing, the larynx is pulled ...

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