In medicine, the nasopharynx is the tripartite nasopharyngeal space composed of the nasopharynx, laryngeal pharynx, and oral pharynx. The muscles of the nasopharynx separate the alimentary canals from the respiratory tract. One of the most common complaints of this anatomical structure is pharyngitis.
What is the nasopharynx?
The nasopharynx is the pharyngeal portion located below the base of the skull and above the palatine cone behind the nasal cavity. It is also known as the nasopharynx and corresponds to a fibromuscular tube structure. The mouth and nasal cavity meet in this anatomical structure in a common respiratory and feeding pathway located dorsal to the oral and nasal cavities. This common pathway extends down the esophagus to the larynx and base of the skull. The nasopharynx is thus up to 15 centimeters long. Three distinct sections make up the nasopharynx: the hypopharynx, the epipharynx, and the mesopharynx. The boundaries of these three sections are not firmly defined. Toward the dorsal wall and the lateral walls, the nasopharynx consists of several muscles of the floor of the pharynx. These so-called pharyngeal muscles extend into the esophagus, where they form Laimer’s triangle and Killian’s triangle. The blood supply to the nasopharynx is provided by six arteries. Venous drainage occurs via the dorsal pharyngeal plexus.
Anatomy and structure
The hypopharynx extends from the larynx to the cricoid cartilage. There it merges with the esophagus. Beneath the epiglottis, this area is the separation of the respiratory and alimentary tracts. While the hypopharynx is also known as the laryngeal pharynx, the mesopharynx is called the oral pharynx. The muscles of the mesopharynx merge into the membrane between the os occipitale and the atlas vertebrae. The dorsal aspect of this muscle bears a suture of connective tissue. In the throat, the mesopharynx is in open communication with the oral cavity and is adjacent to the soft palate. The epipharynx is the nasopharynx. The roof of this nasopharynx consists largely of lymphoid tissue. The nasopharynx communicates with the nasal cavities via choanal openings. A tuba auditiva opens into the nasopharynx from each of the middle ears in the lateral wall of the nasopharynx. These orifices are surrounded by lymphoid tissue. The auditory tube cartilage continues into the nasopharynx as a mucosal fold, also called the tubal pharyngeal fold. The so-called tubopharyngeal muscle runs underneath it. Towards the palate, the nasopharynx forms the tubopharyngeal fold. Behind it lies a mucosal pocket, also known as the Rosenmüller pit.
Function and tasks
The nasopharynx connects the nasal cavities to the trachea, and the oral cavity is connected to the esophagus in this area. Thus, the respiratory and food pathways cross each other in the nasopharynx. To prevent inhalation of food particles in view of this proximity, the muscles of the nasopharynx perform important tasks. During swallowing, for example, the muscles of the nasopharynx are automatically contracted. Chewed food particles are thus transported downward. At the same time, however, the contraction also places the eppiglottis over the laryngeal inlet, resulting in a seal. Aspiration of food particles is thus prevented as far as possible. The entire musculature of the nasopharynx originates from the embryonic pharyngeal pouches and is therefore largely controlled involuntarily. The auditory tube, which opens into the nasopharynx, also performs important functions in equalizing pressure in the middle ear. Due to its confluence with the complex structures of the nasopharynx, humans can even bring about pressure equalization voluntarily by swallowing or holding their breath. This is particularly necessary when rapidly passing through large differences in altitude or pressure. When flying or diving, for example, the pressure conditions in the middle ear no longer match the external pressure conditions. Swallowing and holding your breath can help the auditory tube adjust in these situations.
Diseases
The nasopharynx can be affected by diseases of various types and severity. Pharyngitis, for example, is a comparatively harmless disease of this anatomical structure. It is a mostly painful inflammation of the mucous membrane in the throat area. Normally, this inflammation is preceded by a disease of the upper respiratory tract.Pathogens can ideally spread in the structure of the nasopharynx and from here to different parts of the body. Most congenital diverticula are just as harmless as pharyngitis. The doctor speaks of diverticula in the nasopharynx in the case of bagginess in the nasopharynx. In contrast, a more serious disease of the nasopharynx is diphtheria. This disease is due to toxins produced by an infectious agent. Yellowish coating settles in the nasopharynx. If this pseudomembrane spreads to the trachea, then in the worst case there is even a danger of suffocation. The nasopharynx is sometimes also affected by tumors. Malignant pharyngeal cancer usually metastasizes to the cervical lymph nodes. Most commonly, pharyngeal cancers are malignant squamous cell carcinomas. Approximately one in 100,000 people in Central Europe develop new cases of pharyngeal cancer each year. In Asia, the disease is more common, with men being particularly affected. In most cases, pharyngeal cancer first affects the roof and side walls of the nasopharynx. However, the tumors spread relatively quickly to the nasal cavities and damage cranial nerves. However, there are also benign tumors in the nasopharynx. One example is the so-called Tornwaldt cyst, which particularly affects the posterior nasopharynx.
