Subregions of oral cavity

解剖学教材中对于口腔亚解剖区域的定义大多语焉不详。建议参考AJCC的定义。

The oral cavity extends from the portion of the lip that con- tacts the opposed lip (wet mucosa) to the junction of the hard and soft palate above, to the line of circumvallate papillae below, and to the anterior tonsillar pillars laterally. It is additionally divided into multiple specific sites.

Mucosal lip

The mucosal lip begins at the junction of the wet and dry mucosa of the lip (the anterior border of the portion of the lip that comes into contact with the opposed lip) and extends posteriorly into the oral cavity to the attached gingiva of the alveolar ridge. 

The dry vermilion lip and vermilion border is staged using the chapter on cutaneous carcinoma of the head and neck. This is a change from past AJCC editions where the dry vermilion was included in the lip and oral cavity chapter.

(作者注：此前对唇黏膜的定义是唇红缘、干湿线及口角之间的黏膜，而干湿线以内唇内侧的黏膜定义为颊黏膜，这个8th AJCC cancer staging manual 定义与之前不同，但是和下面颊黏膜的定义又产生了重叠。)

Buccal Mucosa

The buccal mucosa includes all the mucous membrane lining of the inner surface of the cheeks and lips from the line of contact of the opposing lips to the line of attachment of mucosa of the alveolar ridge (upper and lower) and pterygo-mandibular raphe.

Alveolar ridge

1. Lower Alveolar Ridge

The lower alveolar ridge refers to the mucosa overlying the alveolar process of the mandible, which extends from the line of attachment of mucosa in the lower gingivobuccal sulcus to the line of attachment of free mucosa of the floor of the mouth. Posteriorly, it extends to the ascending ramus of the mandible.

2. Upper Alveolar Ridge

The upper alveolar ridge refers to the mucosa overlying the alveolar process of the maxilla, which extends from the line of attachment of mucosa in the upper gingivobuccal sulcus to the junction of the hard palate. Its posterior margin is the upper end of the pterygopalatine arch.

Retromolar Gingiva (Retromolar Trigone)

The retromolar gingiva, or retromolar trigone, is the attached mucosa overlying the ascending ramus of the mandible from the level of the posterior surface of the last lower molar tooth to the apex superiorly, adjacent to the tuberosity of the maxilla.

Floor of the Mouth

The floor of the mouth is a crescentic surface overlying the mylohyoid and hyoglossus muscles, extending from the inner surface of the lower alveolar ridge to the undersurface of the tongue. Its posterior boundary is the base of the anterior pillar of the tonsil. It is divided into two sides by the frenulum of the tongue and harbors the ostia of the submandibular and sublingual salivary glands.

Hard Palate

The hard palate is the semilunar area between the upper alveolar ridge and the mucous membrane covering the palatine process of the maxillary palatine bones. It extends from the inner surface of the superior alveolar ridge to the posterior edge of the palatine bone.

Anterior Two-Thirds of the Tongue (Oral Tongue)

The anterior two-thirds of the tongue is the freely mobile portion of the tongue that extends anteriorly from the line of circumvallate papillae to the undersurface of the tongue at the junction with the floor of the mouth. It is composed of four areas: the tip, the lateral borders, the dorsum, and the undersurface (nonvillous ventral surface of the tongue). The undersurface of the tongue is considered a separate category by the World Health Organization (WHO).