12, 14, 15, 16, 17, 18 Finally, there are numerous texts describing, in detail, the embryologic history of the ultimate adult structures. 11, 12, 13 Additionally, there are numerous texts with a more physiologic outlook, that integrate some portion of anatomy with a more specific functional focus. 1, 8, 9, 10 Because the substance of anatomy has changed little over the years, some of the older texts are still both relevant and useful. Recent developments in imaging and publishing extend this tradition. 4, 5, 6, 7 Historically, anatomic atlases provide morphologic detail beyond that available in texts. There are many excellent texts of anatomy, replete with extensive detail.
A functional approach, starting with the physiology and mechanics of structures, followed by a description of the sensory and motor mapping to relevant structures is useful for the application of anatomy to understanding normal function, as well as chronic and traumatic dysmorphology. This approach is very useful for those working with the impact of morphologic birth anomalies on function, as well as the repair of those anomalies. 1, 2, 3 Because the embryology follows the evolutionary origin of these spaces, it has the virtue of delineating the evolutionary constraints of the spaces, and explaining some of the design flaws with respect to function.
One classic approach is based on embryology and the developmental history of these spaces. There are several ways of describing the specifics and details of these spaces and the structures that bound them. The palatine tonsils are bilateral structures in the oropharynx, and lingual tonsils lie on the posterior portion of the tongue. The pharyngeal tonsil is found in the roof of the nasopharynx. Various tonsils, composed of lymphoid tissue, are found in the pharynx. In its anterior/inferior aspect, the pharynx joins the larynx the adjacent lower portion is often referred to as the "hypopharynx" or the "laryngopharynx." In its anterior/superior potion the pharynx joins the nasal cavity and this upper portion is called the "nasopharynx." The midportion of the pharynx, where it joins the oral cavity, is called the "oropharynx." Thus the tongue lies in both the oral cavity and the pharynx.
The boundaries of the pharynx are the mouth and the nasal choanae anteriorly the soft palate, or velum, and portions of the skull base superiorly the posterior tongue inferiorly and the pharyngeal constrictors posteriorly. The arrow (b, bottom left) represents the path that food takes through the piriform recesses, which lie on either side of the laryngeal opening. The esophagus and pharynx have been opened to show the connections of the nasal cavity, oral cavity, larynx, and esophagus into the pharynx. In this view, the spinal column has been removed, so that the view is into the pharynx. b: Posterior view of the oral cavity and pharynx.
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