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Anatomy Insight |  Comic  Sans | Lexend

The nasopharynx lies behind the nasal cavity and above the soft palate. It communicates with the nasal cavity through the choanae and functions only as an airway. 

In its roof is the pharyngeal tonsil (adenoid), a mass of lymphoid tissue that helps trap pathogens, especially in children. 

On each lateral wall is the opening of the auditory (Eustachian) tube, surrounded by the torus tubarius. These tubes connect the nasopharynx with the middle ear, explaining why infections of the throat or nose may spread to the ear. 

During swallowing, the soft palate and uvula elevate to close off the nasopharynx and prevent food from entering the nasal cavity. 

• The nasopharynx is lined mainly by pseudostratified ciliated columnar epithelium.

The oropharynx lies behind the oral cavity and extends from the soft palate to the upper border of the epiglottis. It communicates with the mouth through the fauces and serves as a passageway for both air and food.

The laryngopharynx lies behind the larynx and extends from the epiglottis to the esophagus. It is the lower part of the pharynx where the respiratory and digestive pathways diverge. 

Anteriorly it opens into the larynx, while posteriorly it continues into the esophagus. On each side of the laryngeal opening are the piriform recesses. The laryngopharynx is also lined by stratified squamous epithelium.

The wall of the pharynx consists of mucous membrane, submucosa, and a muscular coat. The upper part contains the pharyngobasilar fascia, a fibrous layer attached to the base of the skull. 

The muscular layer is mainly formed by three circular constrictor muscles (superior, middle, and inferior constrictors) which overlap each other and meet posteriorly at the pharyngeal raphe. 

These muscles contract during swallowing to propel food downward into the esophagus. Longitudinal muscles such as the stylopharyngeus and salpingopharyngeus elevate the pharynx during swallowing and speaking.