Extrinsic Muscles

EXTRINSIC MUSCLES

According to Jones and Bernes (2020), the extrinsic muscles move the larynx upward and downward. The suprahyoid, infrahyoid, and stylopharyngeus (a muscle of the pharynx).

The hyoid bone attaches the supra- and infrahyoid muscle. This is attached to the larynx by strong ligaments, allowing the larynx to move as a unit.

The suprahyoid and stylopharyngeus muscles raise the larynx, whereas the infrahyoid muscles depress it.

To allow laryngeal movement to occur, extrinsic larynx muscles are coupled or are paired up.

The thyrohyoid muscle attaches to the thyroid cartilage and the hyoid bone's body. Along with the hypoglossal nerve, this gets innervation from the first cervical nerve. Its principal purpose is to elevate the larynx by depressing the hyoid bone (Suárez-Quintanilla et al., 2020).

The sternothyroid muscles are located behind the sternohyoideus muscle; they originate in the sternum and first rib and extend to the thyroid cartilage's lamina, where they are innervated by the ansa cervicalis. These muscles act to constrict the larynx.

The inferior pharyngeal constrictor muscles are located from the cricoid and thyroid cartilages to the pharyngeal raphe, . These muscles are innervated by the vagus nerve through branches of the pharyngeal plexus and the recurrent laryngeal nerve and contribute to swallowing by narrowing the pharynx diameter.

The stylopharyngeus muscles extend from the temporal bone's styloid process to the thyroid cartilage. These muscles are supplied by the glossopharyngeal nerve and have the role of elevating the larynx and pharynx.

Palatopharyngeus muscles originate from the palatine aponeurosis and pterygoid processes and enter into thyroid cartilage. They are a component of the soft palate, are innervated by the pharyngeal branch, and have the function of elevating the larynx and pharynx. blark

Other muscles that are not strictly laryngeal in nature because they do not have laryngeal insertions may also contribute to the movement of the larynx, such as the geniohyoid, mylohyoid, digastric, or stylohyoid muscles, which elevate the larynx, and the omohyoid and sternohyoid muscles, which cause laryngeal depression (Suárez-Quintanilla et al., 2020).