The gingivae (gums) are the mucous lined extensions from the floor and roof of the oral cavity which contain the teeth. The gingivae is divided into attached (closely bound to the alveolar processes of the mandible / maxilla) and free (loose tissue which is continuous with the lips/cheeks/floor of mouth/palate). They are covered by keratinising squamous epithelium and have minimal submuscosal tissue.
The point of reflection of the lips and cheek mucosa onto the gingivae is known as the fornix vestibuli. Between the gingivae and the lips and cheek may be small frenulums of loose connective tissue, which have no functional role.
The gingiva cover the alveolar process and roots of the teeth.
Externally, the gingiva are related to the lips and cheeks, separated by the oral vestibule.
The tongue, palate and oral cavity proper lie internally.
The attached gingiva typically has a pale, stippled appearance although this varies widely. The free gingivahas no stippling and is normally bright red.
The gingiva proper is covered by keratinising stratified squamous epithelium, as opposed to the alveolar gingiva which is non-keratinising.
The appearance of the gingivae varies markedly between people, based on race, age and the general health of the gingivae and teeth.
The buccal gingivae of both the maxilla and mandible are supplied by branches of the buccal artery (a branch of the 2nd part of the maxillary artery), as well as branches of the posterior superior alveolar artery. The palatine gingivae are supplied by branches of the greater palatine artery. The mandibular labial gingivae receive blood from the incisive artery and mental artery (terminal branches of the inferior alveolar artery). The maxillary labial gingivae are supplied by branches of the anterior superior alveolar artery and the labial branches of the infraorbital nerve. Finally, the lingual gingivae are supplied by the lingual artery and the lingual branch of the inferior alveolar artery.
The veins of the gingivae are not well described, but most are believed to pass laterally and posteriorly to the pterygoid venous plexus. The lingual gingivae may drain along lingual veins directly to the internal jugular vein.
Lymph drainage from the gingivae depends on the site. With the exception of the labial gingivae of the mandible, the labial, buccal and palatine gingivae drain to submandibular lymph nodes. The labial gingivae of the mandible drains to the submental nodes. The lingual gingivae drains directly to superior deep cervical nodes (level 2).
The mandibular gingivae are innervated by various branches of the mandibular division of the trigeminal nerve (lingual nerve, buccal nerve, inferior alveolar nerve and its two terminal branches)
The maxillary gingivae are wholly innervated by branches of the maxillary nerve, including the nasopalatine, greater palatine, anterior/middle/posterior superior alveolar and infraorbital nerves.
Routes of Cancer Spread
Tumours of the gingivae are very rare.
Gingival SCC may extend into the alveoli of the mandible or maxilla, causing pain or loss of teeth.
Most regions of the labial/buccal gingivae have lymphatic drainage to the submandibular nodes. The only exception is the gingivae around the mandibular incisors which may drain to submental nodes first. The palatine and lingual gingivae
The upper gingiva is supplied by branches of the maxillary nerve V2, and the mandibular gingiva is supplied by branches of the mandibular nerve V3. These are important nerves to examine when perineural invasion is present.
If present, SCC may spread to lung, bone and then liver.