Extraoral anatomy in CBCT – a literature review. Part 4: Pharyngocervical region.

This review about extraoral anatomy depicted in cone beam computed tomography describes the pharyngocervical region. Large (≥ 8 × 8 cm) field of views of the maxilla and/or mandible will inevita-bly depict the pharyngocervical region that com-prises the posterior upper airway, the pharyngeal part of the digestive tract, as well as the cervical segment of the spine. The latter consists of seven cervical vertebrae (C1-C7) with corresponding distinctive features, i.e., the atlas (C1) and the axis (C2). In addition, cervical vertebrae serve as ref-erences for the vertical position of anatomical structures. For instance, C4 is a typical landmark since it generally denotes the level of the chin, of the body of the hyoid bone, of the base of the epiglottis, and of the bifurcation of the common carotid artery, respectively. The pharynx, which is functionally involved in respiration, deglutition, and vocalization, extends from the lower aspect of the skull base to the esophagus. Anatomically, the pharynx is divided into three segments, i.e. the nasopharynx, the oropharynx, and the laryn-gopharynx. All communicate anteriorly with cor-responding cavities, i.e. the nasal cavities, the oral cavity, and the larynx. Although not directly located within the pharyngocervical region, the hyoid bone and the styloid process are also dis-cussed in this review, since both structures are commonly visible on CBCT images of this region.