Imaging Diseases of the Pharynx and Oral Cavity

Abstract

The pharynx is subdivided into the nasopharynx, oropharynx, and hypopharynx. The nasopharynx joins the oropharynx at the level of the hard and soft palates, while the hypopharynx is the continuation of the oropharynx into the piriform sinus below the level of the pharyngo- and aryepiglottic folds. The pharynx is formed by the superior, middle, and inferior constrictor muscles. The nasopharynx is attached to the skull base by the pharyngobasilar fascia, a musculo-aponeurotic continuation of the middle layer of the deep cervical fascia (ML-DCF) that invests the pharyngeal muscles [1]. The ML-DCF represents the anterior wall layer of the retropharyngeal space. The suprahyhoid retropharyngeal space houses fat and medial and lateral (Rouviere) lymph nodes. It is separated by a transversely oriented duplication of the deep layer of the deep cervical fascia (DL-DCF) from the danger space and the perivertebral space. The ML-DCF and the constrictor pharyngeal muscles house the pharyngeal mucosal space and Waldeyer’s lymphatic ring with adenoid tissue in the roof of the nasopharynx and the faucial and lingual tonsils within the oropharynx.