1-33. ANATOMY AND PHYSIOLOGY OF THE THROAT AND NECK
The word throat refers to those structures of the neck in front of the vertebral
column, including the mouth, tongue, pharynx, tonsils, larynx, and trachea.
a. The Mouth. The mouth extends from the lips to the anterior pillars of the
fauces. The portion of the mouth outside the teeth is known as the buccal cavity and
that on the inner side of the teeth as the lingual cavity. The tongue occupies a large
portion of the floor of the mouth. The hard and soft palates form the upper and posterior
boundaries of the oral cavity, separating it from the nasal cavity and the nasopharynx.
The soft palate emerges from the posterior border of the hard palate to form the uvula, a
fingerlike movable projection. On either side, the uvula is adjacent to the base of the
tongue anteriorly and the pharynx posteriorly.
b. The Pharynx.
(1) The pharynx serves as a channel for both the digestive and respiratory
systems. It is situated behind the nasal cavities, mouth, and larynx. The food and air
passages cross each other in the pharynx. The pharynx is a funnel-shaped structure,
wide above and narrower below, about 12 cm in length. It is composed of muscular and
fibrous layers and lined with mucous membrane. It is associated above with the
sphenoid and the basilar part of the occipital bone. Below, it joins the esophagus.
Seven cavities communicate with the pharynx: the two nasal cavities, the two tympanic
cavities, the mouth, the larynx, and esophagus. The cavity of the pharynx may be
subdivided from above downward into three parts: nasal, oral, and laryngeal. Infection
may spread from the pharynx to the middle ear via the auditory tube. This auditory tube
can be catheterized through the nostril.
(2) The nasopharynx communicates with the oropharynx through the
pharyngeal isthmus, which is closed by muscular action during swallowing. The
oropharynx and the laryngopharynx cannot be closed by muscular action during
swallowing. The oropharynx and the laryngopharynx cannot be closed off from each
other; both service respiratory and digestive functions.
(3) The pharynx is made up of three groups of constrictor muscles. Each
muscle fits within the one below, and each inserts posteriorly in the median line with its
mate from the opposite side. The constrictor muscles provide constriction of the
pharynx for dilatation. Between the origins of the constrictor muscle groups, there are
so-called intervals through which pass ligaments, nerves, and arteries. The recurrent
laryngeal nerve is closely associated with the lower portion of the pharynx.
c. The Tonsils.
(1) The tonsils are situated one on each side of the oropharynx, lodged in a
tonsillar fossa that is attached to folds of membrane containing muscle. One pair, the
palatine tonsils, is the only lymphatic organ covered with stratified squamous epithelium.