The mouth (Figure CA1) extends from the lips to the isthmus of the fauces. It contains the tongue, alveolar arches that comprise the gums and teeth and the openings of the salivary glands. The mouth may be divided into two sections, the vestibule and the cavity proper.
The vestibule is a slit-like cavity bounded externally by cheeks and lips. The gingivae and teeth provide the boundary to the mouth cavity proper. The mucous membrane is stratified squamous epithelium and the opening of the parotid duct lies just above the second molar crown.
The oral cavity proper is limited by the maxilla anteriorly and laterally. It is roofed by the hard and soft palates. The floor of the cavity mainly consists of the tongue. Posteriorly the oropharyngeal isthmus separates the oral cavity from the oropharynx. The lining consists of mucous membrane, which is stratified squamous epithelium with mucous glands beneath.
Each tooth has a crown, a neck and roots that penetrate the alveolar bone. The central cavity of the tooth is filled with pulp and surrounded by dentine. At the crown the dentine is covered by enamel whereas the dentine of the root is covered by cementum. Within the alveolar socket the periodontal membrane fixes the tooth in position.
The teeth of the upper jaw are supplied by the anterior and posterior superior alveolar nerves whereas the teeth of the lower jaw are supplied by the inferior alveolar nerve.