Larynx

The larynx (also known as the voice box) is located between cervical vertebra C3 - C6 and is continuous with the trachea. It has a few important functions including:

1. Breathing

2. Phonation

The mucous membrane that lines the larynx gives rise to two pairs of folds: the upper folds are the vestibular folds (also known as false vocal folds) that do not contribute to vocalization and the lower folds are the vocal folds (also known as the true vocal folds) that produce the sounds required for speech and other vocalizations. During respiration, the vocal folds remain open to allow passage of air through the larynx.

The parts of the larynx can be categorized as:

Blood Supply

The superior and inferior laryngeal arteries supply the larynx.

1. Superior Laryngeal Artery

   • The external carotid artery gives rise to the superior thyroid artery.

   • The superior thyroid artery gives rise to the superior laryngeal artery

2. Inferior Laryngeal Artery

   • The subclavian artery gives rise to the thyrocervical trunk

   • The thyrocervical trunk gives rise to the inferior thyroid artery gives rise to the superior laryngeal artery.

The superior and inferior laryngeal veins drain the larynx.

Innervation

The larynx is innervated by branches of the vagus nerve:

1. Recurrent laryngeal nerve 

   • Provides sensory innervation to the infraglottis

   • Provides motor innervation to all the internal muscles of larynx (except cricothyroid).

2. Superior laryngeal nerve 

   • Provides sensory innervation to the supraglottis

   • Provides motor innervation to the cricothyroid muscle.