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Physical examination of the oral cavity  

Examination of the oral cavity should be carried out with adequate lighting from an external source such as fixed or head-mounted examination lights or hand-held flashlights, supplemented by room lighting (figure 1A, figure 1B and (figure 1C)). The procedure should be explained to the person and every effort should be taken to ensure that the subject is relaxed and not anxious. Anxiety during examination may cause a temporary dryness of the mouth. Palpation should be carried out wearing gloves. Tongue depressor, mouth mirrors and gauze sponges are essential tools for adequate examination of the intraoral structures. Oral mucosa is generally pink in colour. Highly keratinized, firm, stippled and pale masticatory mucosa cover the hard palate, dorsal surface of tongue, and gingiva. Thin, less keratinized and more pinkish non-masticatory mucosa cover the remaining intra-oral structures. The examiner should be alert during the entire procedure to identify any change in colour and/or texture of the mucous membrane, inflammatory areas, erythema, hyperpigmentation, macules, papules, vesiculobullous lesions, white lesions, grayish white lesions, red lesions, induration, ulceration, swellings and growth in the oral mucosa.

Oral examination commences with the visual examination of the lips and the vermilion border (figures 2) and by palpation after removing any lipstick. The lip is usually smooth and pliable. Maceration and cracking of the corners of the lips indicate angular cheilitis. Evert the lips and carefully inspect the labial mucosa (figure 3). It should be smooth, soft and well-lubricated by minor salivary glands that can be palpated. One may observe a mucocele in the lower lip resulting from trauma to the minor salivary gland ducts, as the lower lip is frequently prone to injury, particularly from accidental biting.

The buccal mucosa is examined by stretching it with a pair of tongue depressors or mouth mirrors after the subject partially opens the mouth (figures 4). In people with dark skin, one may frequently observe a benign condition called leukoedema, which is characterized by a diffuse greyish white opalescence in the buccal mucosa; this disappears when the tissue is stretched. A horizontal white or grey line, along the buccal mucosa, called linea alba buccalis may be observed in some persons (figure 5). This is a benign, hyperplastic reaction resulting from the chronic irritation from the teeth cusps at the level of the interdigitation of the teeth. The opening of the parotid salivary gland duct, the Stensen duct, may be observed as a small papillary or punctate soft tissue mass on the buccal mucosa adjacent to the maxillary second molar tooth. Milking of the parotid gland may expel saliva at the duct opening. Ectopic sebaceous glands may be observed on the buccal or labial mucosa as whitish-yellow, pinpoint papules; this developmental anomaly is termed as Fordyce conditions or granules (figure 6). Minor salivary glands and Fordyce granules may lead to a granular feel on palpation of the buccal mucosa.

After examination of the buccal mucosa, the dorsal surface of the tongue is examined by asking the subject to protrude the tongue and attempt to touch the tip of the chin (figure 7); alternatively the tip of the tongue may be held gently by the fingers and a gauze sponge (figure 8). The dorsal surface of the tongue is normally uniformly covered by numerous fine-pointed and cone-shaped filiform papillae; dozens of mushroom-shaped fungiform papillae, each of which contains one or more taste buds are interspersed among them. The filiform papillae may occasionally become elongated (hairy tongue) and collect oral debris, which can lead to bad breath (halitosis) and an uncomfortable palatal sensation that may lead to gagging. The circumvallate papillae containing numerous taste buds, 8–10 in number arranged in a V-shaped fashion, are located at the junction of the anterior two thirds and posterior third of the tongue. Occassionally, fissuring of the dorsal surface of the tongue may be observed. Nutritional deficiencies may lead to atrophy of the tongue with altered taste sensations or even complete loss of taste.

The lateral borders of the tongue are examined by grasping the tip of the tongue with a gauze sponge, extending and rotating it laterally (figure 9) and retracting the buccal mucosa on the same side with the tongue depressor. Alternatively, the lateral border of the tongue can be examined by asking the person to touch the opposite buccal mucosa with the tip of the tongue and retracting the buccal mucosa with a mouth mirror (figure 10). Vertical fissuring may be observed more along the lateral border of the tongue. Collections of accessory lymphoid tissue (lingual tonsil), with a bosselated surface, can be found at the base of the tongue, posteriorly. This is a component of the Waldeyer ring and may become enlarged in the presence of infection or inflammation.

The ventral surface of the tongue and the floor of the mouth are most easily visualized by having the person touch the tip of the tongue to the roof of the mouth (figure 11). A high level of clinical alertness is required when examining these sites, where oral cancers may be missed as red or white innocuous-looking lesions. Folds of tissue, the plica sublingualis, can frequently be observed extending from the ventral surface of the tongue. The saliva pooled in the floor of mouth during an oral examination is removed with a gauze sponge. The openings of the submandibular ducts, the Wharton ducts (figure 12), are usually visualised as midline papillae on either side of the lingual frenum (figure 13). Saliva oozes out of the Wharton ducts when the submandibular salivary glands are bimanually palpated.

The gingivae are examined with the mouth partially opened and the lips retracted with the fingers, a tongue blade, or plastic lip retractor (figure 14A and figure 14B). The attached gingivae adjacent to the teeth appear pale, firm and firmly attached to the underlying bone and are frequently pigmented. The gingival mucosa is darker in colour than the rest and extends from the mucogingival junction to cover the buccal sulcus. Alterations in the clinical appearance of the gingivae can be an indicator of both localized and systemic disease. Poor dental hygiene results in retained dental plaques and calculus formation, which can serve as a nidus for infection leading to gingival inflammation, reactive ginigival lesions such as pyogenic granuloma, periodontal disease and involvement of underlying supportive structures of the teeth. The gingiva is often affected in HIV infection and may be the first indicator of immunosuppression. The anterior part of the hard palate is better visualised using an intraoral mirror (figure 15). The anterior portion of the hard palate is covered by many fibrous ridges. The presence of a large number of minor salivary glands makes the hard palate a common location for minor salivary gland tumours. The soft palate is examined by depressing the base of the tongue with a tongue depressor and asking the subject to say “aah” (figure 16). Part of the oropharynx, particularly the accessory lymphoid tissues in the posterior pharyngeal wall that appear as pale mucosal papules, is visible during this procedure. The tonsillar pillars are examined by moving the tongue laterally. Accumulation of desquamated epithelial cells and food may present in the tonsillar crypts as debris.

Examination of the teeth should be the final part of the oral examination. Missing teeth and/or supernumerary teeth may be observed. Discoloured cavities in the occlusal surfaces of teeth may be observed as a consequence of poor oral hygiene.

Clinical examination of the head and neck is an integral part of oral examination and provides valuable information on the overall assessment of possible oral diseases. The examination for cervical lymph glands is carried out by standing behind the individual and slightly flexing and bending the neck to the side so that the sternocleidomastoid muscle becomes relaxed and palpation and identification of any enlarged nodes will be easier (figure 17). The presence of neck masses is not an uncommon finding, especially in subjects with oral infections or cancer. The submandibular, submental and upper deep cervical lymphnodes are commonly involved, although other regional lymph nodes may be enlarged as well. Lymphadenopathy secondary to infection will be tender and mobile, while metastatic lymph nodes are often asymptomatic, hard in consistency, and may be fixed to the underlying structures. The next most common head and neck mass found on palpation is a salivary gland tumour. Bimanual palpation is useful in differentiating submandibular salivary gland swellings from enlarged submandibular lymph nodes. Parotid neoplasm is observed as a diffuse swelling in front of the ear or over the angle of the jaw, often lifting the ear lobule (figure 18A and figure 18B). Extension of oral cancer into the oral soft tissues and to the skin of the face may be evident as diffuse swelling of the cheek or maxillary area, skin induration, skin nodules, ulceration, and in extreme cases as orocutaneous fistula.

Temporomandibular joint pain and dysfunction, as characterized by the presence of crepitation, clicking and popping of the joints, may be detected by placing the tip of the little finger in the external auditory canal and having the person open and close the mouth and by moving the mandible laterally from side to side.

Image	Caption
	Figure 1A: Physical examination under bright daylight.
	Figure 1B: Oral examination using head mirror.
	Figure 1C: Oral examination with torch and wooden spatula.
	Figures 2: Examination of the lips.
	Figure 3: Examination of the labial mucosa.
	Figures 4: Examination of the buccal mucosa. Buccal mucosa is examined by retracting it with wooden spatulas or mouth mirrors, after the subject opens the mouth partially in a relaxed position.
	Figure 5: Linea alba buccalis. Note the linear, white, keratotic fold (arrow) on the left buccal mucosa that runs parallel to the occlusal plane.
	Figure 6: Fordyce granules (arrows). Note the small yellowish nodules on the right buccal mucosa.
	Figure 7: The dorsal surface of the tongue is examined by asking the person to protrude the tongue and attempt to touch the tip of the chin.
	Figure 8: The tip of the tongue may be held gently by the fingers and a gauze sponge.
	Figure 9: The lateral borders of the tongue are examined by grasping the tip of the tongue with a gauze sponge, extending and rotating it laterally.
	Figure 10: The lateral border of the tongue can be examined by asking the person to touch the opposite buccal mucosa with the tip of the tongue and retracting the buccal mucosa with a mouth mirror.
	Figure 11: The ventral surface of the tongue and the floor of the mouth are most easily visualized by having the person touch the roof of the mouth with tip of the tongue.
	Figure 12: Opening of Wharton duct (yellow arrows).
	Figure 13: Median frenum of tongue (yellow arrow).
	Figure 14A: The gingivae are examined with the mouth partially opened and lips retracted with mouth mirrors.
	Figure 14B: Examination of the gingivae is carried out with the mouth partially opened and the lips retracted with mouth mirrors.
	Figure 15: The anterior part of the hard palate is better visualised using a mouth mirror.
	Figure 16: The soft palate is examined by depressing the base of the tongue with a mouth mirror and asking the subject to say “aah”.
	Figure 17: The examination for cervical lymph nodes is carried out by standing behind the individual and slightly flexing and bending the neck to the side so that the sternocleidomastoid muscle becomes relaxed and palpation and identification of any enlarged nodes will be easier.
	Figure 18A: Patient with enlarged metastatic right upper deep cervical lymph node on the right side (arrow).
	Figures 18A and 18B: Pleomorphic adenoma of the right parotid gland. The ear lobule is pushed upwards and backwards by the tumour, which helps to differentiate parotide tumour from enlarged upper deep cervical lymph node.
	Figure 19: Carcinoma of the left parotide gland infiltrating the overlying skin.