QS Study

Extrinsic and Intrinsic muscles of Larynx and their Nerve Supply

The larynx is the organ for phonation. It is an organ located in the anterior neck. It goes from the root of the tongue to the trachea and is located in front of the 3rd, 4th, 5th, and 6th cervical vertebrae. It is a component of the respiratory tract.

The muscles of the larynx can be divided into two groups; the external muscles and the internal muscles. It contains many extrinsic and intrinsic muscles which are mentioned below with their nerve supply.

(A) Extrinsic muscles: The extrinsic muscles act to move the larynx superiorly and inferiorly.

Name of muscles and their Nerve supply –

  • Digastric – Anterior belly by the nerve to mylohyoid, posterior belly by the facial nerve.
  • Mylohyoid – Nerve to mylohyoid.
  • Stylohyoid – By facial nerve.
  • Geniohyoid – A branch of hypoglossal nerve containing C1 nerve fibers.
  • Stylopharyngeus – By glossopharyngeal nerve.
  • Salpingopharyngeus – By cranial part of the accessory nerve.
  • Palatopharyngeus – By cranial part of the accessory nerve.
  • Sternothyroid – By Ansa cervicalis.
  • Sternohyoid – By Ansa cervicalis.
  • Omohyoid – Superior belly by a superior root of ansa cervicalis, inferior belly by an inferior root of ansa cervicalis.

Extrinsic muscles of Larynx 2

Fig: Extrinsic muscles of Larynx

(B) Intrinsic Muscles: They control the shape of the rima glottidis and the length and tension of the vocal folds.

Name of muscles and their Nerve supply –

  • Cricothyroid – By external laryngeal nerve.
  • Oblique arytenoids – By recurrent laryngeal nerve.
  • Transverse arytenoid (vocalic) – By recurrent laryngeal nerve.
  • Thyroarytenoid – By recurrent laryngeal nerve.
  • Thyro epiglotticus – By recurrent laryngeal nerve.
  • Lateral cricoarytenoid – By recurrent laryngeal nerve.
  • Posterior cricoarytenoid – By recurrent laryngeal nerve.

Intrinsic muscles of Larynx 1

Fig: Intrinsic muscles of Larynx

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