Floor of the Mouth

The floor of the mouth is examined using direct and indirect vision followed by bimanual palpation of the entire area. The patient should be asked to raise the tongue making direct visual examination of the tissues toward the midline of the floor of the mouth possible (Figure 44).

Figure 44. Visual examination of the floor of the mouth. Note the normal structures of the area.
Visual examination of the floor of the mouth. Note the normal structures of the area.

The mirror should be used to examine the areas near the inferior border of the mandible. The tissues should appear moist and very vascular. The normal anatomy of the area should be identified (Figure 44) including:

  • Sublingual caruncle – small rounded projection at the base of the lingual frenum which houses Wharton’s duct from the submandibular salivary gland
  • Sublingual folds – two oblique elevations found radiating laterally away from the lingual frenum on either side of the caruncle which house the ducts from the sublingual salivary gland
  • Lingual frenum – muscle attachment from the ventral surface of the tongue to the floor of the mouth. This attachment varies in length from person to person.

Bimanual intraoral palpation with the index finger of the nondominant hand supported extraorally by the fingers of the dominant hand will allow the clinician to feel the structures of the area between the fingers as they are compressed together gently (Figures 45 and 46).

Figure 45. Extraoral view of proper palpation technique.
Extraoral view of proper palpation technique
Figure 46. Intraoral view.
Intraoral view

The tissue will be soft on palpation with firmer areas noted in the area of the suprahyoid muscles (digastric, geniohyoid, mylohyoid). The sublingual folds will feel ridge-like and mobile. Varicosities are the most common atypical observation in this area. Other atypical findings are enlarged lingual folds and caruncle and a short lingual frenum (ankyloglossia). Ankyloglossia is only considered a problem if it begins to affect the speech development of the individual. Pathologic findings include:

  • Traumatic injuries – ulcers (Figure 47), mucoceles
  • Salivary gland pathology – ranula, sialoliths, enlargement
  • Neoplastic changes
  • Ankyloglossia – this is considered pathologic only if it interferes with the normal development of proper speech
Figure 47. Traumatic ulcers resulting from intraoral radiographs.
Traumatic ulcers resulting from intraoral radiographs
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