Site or location

This section will review the major soft tissue sites included in an oral examination. The boundaries of each site and important anatomical structures or landmarks will be emphasized.

When any abnormal change or lesion is detected, you must have a clear understanding of its exact location. Proper recording of location in the record will be mutually understood by any person reading the chart.

The following descriptions lead you on a tour of the oral cavity and its environment. Click on any link to see a picture of what is being described. Practice locating the areas described on a real person, for example a classmate.

The oral cavity

Space The oral cavity is the oval shaped space bounded anteriorly by the lips, laterally by the cheeks, superiorly by the palate, and inferiorly by the floor of the mouth.

It communicates externally through the opening between the lips and internally with the pharynx through the fauces or tonsillar pillars.

The oral cavity is subdivided by the alveolar processes and the teeth into the oral cavity proper and theoral vestibule.

The oral cavity proper is the space enclosed within the alveolar processes and the teeth.

The oral vestibule is divided into a posterior and anterior section.

The anterior vestibule exists only with the lips closed.

The lips are two highly sensitive, mobile folds composed of skin, muscle, glands, and mucous membrane. They surround the oral orifice and form the anterior boundary of the oral cavity.

  • The upper lip begins under the nose and extends laterally toward the cheek to the nasolabial sulcusThis depression begins just lateral to the nose and passes downward lateral to the corner of the mouth or commissure.
  • The lower lip is bounded inferiorly by the prominent groove, the labiomental sulcus which tends to deepen with age. Laterally the lower lip may have no distinct border, simply merging with the skin of the cheek.
  • With increasing age, usually a furrow, the labiomarginal sulcus develops at, or close to, the commissure and passes in a convex arch toward the lower border of the mandible.
  • The upper and lower lips are joined at the corners of the mouththe commissures by a thin connecting fold well visible when the mouth is opened.
  • The skin of the lips ends in a sharp, sometimes elevated, line. The transitional zone between the skin and the mucous membrane is known as the red zone or vermilion zone or vermilion border.
  • The vermilion zones end at an imaginary wet line where the lips touch the labial surfaces of the anterior teeth when the lips are closed lightly.

The color of the vermilion zone of the lips is a unique human characteristic. The surface epithelium is non-keratinized, and thus more translucent. The proximity to the surface of the connective tissue papillae, plus the prominent, dilated, and thin capillaries in them, accounts for the color.

The lips vary from pink to red. The more melanin people have in their skin, the more this pigment tends to cause the lips to take on a purple to brown color range.

The texture of the lips is normally smooth, soft, and resilient with minimal fissuring in the young individual. With advancing age and environmental influences, fissuring, thinning of the epithelium, the vermilion zone color is altered and becomes more bluish to purple.

Labial mucosa

Doorway Retraction of the lips away from the teeth andgingiva exposes the labial mucosae.

The labial mucosae are the rectangular areas between imaginary lines drawn from the commissures to the distal surfaces of the upper and lower cuspids, extending from the vermilion border into the vestibule.
  • In the midline of the upper and lower vestibule, a fold of mucosa extends from the mucosal surface to the alveolar mucosa. These are the labial frenula.
  • The color of the labial mucosa is normally pink to purple according to the degree of melanin pigment present. The area is rich in vascularity and minor salivary glands.
  • Stretching of the mucosa will reveal varying degrees of prominent vessels and ductal orifices of the minor salivary glandsThese glands can sometimes cause the surface of the labial mucosa to be nodular or granular.
  • The texture of the labial mucosa is normally smooth, soft, and elastic with the mucosa fixed to the underlying muscle fascia.

Design

  • We will combine the oral vestibule and buccal mucosa since they are confluent, and many lesions involve both sites.
  • The buccal mucosa is bounded above and below by the reflection of the mucous membrane onto the alveolar process.
  • The buccal mucosa is the entire lining mucosa of the cheeks which is confluent anteriorly with labial mucosa and commissure and extends posteriorly to a fold, thepterygomandibular raphe.

The pterygomandibular raphe is a tendinous strip which attaches to the hamular process of the pterygoid plate above and behind the retromolar triangle.

Buccal mucosa and vestibule

 Compass

The buccal mucosa has one important landmark, the parotid papilla which varies considerably from one person to another. In some people it may have a prominent elevation or it may be just a slight indentation. This represents the orifice ofStensen's Duct.

Although the vestibular sulcus or fornix and buccal mucosa are confluent, the vestibular sulcus is the horseshoe-shaped furrow formed by the reflection of the superior and inferior borders of the buccal mucosa and labial mucosa. This area is sometimes referred to as the mucobuccal fold, the buccal gutter, the vestibule, and other terms like "that place between the lips and the front teeth."



Approximately at the middle of the buccal mucosa in most individuals there is a longitudinal fold of tissue extending from a point near the commissure posteriorly to close to the pterygomandibular raphe. This is known as the linea alba buccalis or occlusal line.

The buccal mucosa contains primarily muscle, the buccinator and masseterPosteriorly, it contains theparotid gland and varying amounts of fat which from the buccal fat pad. Scattered throughout the buccal mucosa are numerous minor salivary glands; it may also contain sebaceous glands;

The texture of the buccal mucosa is very similar to the labial mucosa. The mucous membrane is soft and fixed to the inner fascia of the buccinator muscle. In some people the numerous mucous and mixed glands in the submucosal tissue will result in a nodular texture.

There are frequently prominent sebaceous glands or Fordyce's granules adjacent to the commissures and extending to the molar region. These may feel granular to touch.

The buccal fat pad can vary considerably in the degree of prominence. It usually decreases in prominence from childhood into adult life. It is more easily palpated than visualized, and it lies beneath and distal to the parotid papilla.

The vestibular sulcus may have several folds of tissue traversing laterally between the alveolar mucosa and the buccal mucosa. These are the lateral frenula or buccal frenulausually present in the area of the cuspids or bicuspids in both the maxilla and mandible.The mucous membrane of the vestibular sulcus is thin, and the many small blood vessels present are easily seen.

The submucous tissue attaching the mucous membrane to muscles and bone is very loose, allowing for the marked mobility of the lips and buccal mucosa. This mobility decreases in the molar region as does the amount of this loose connective tissue.

Alveolar mucosa and gingiva

 Sea From the vestibular sulcus the mucous membrane continues over the tooth-supporting bone to the cervical areas of the teeth.This area may be subdivided into two zones. The zone adjacent to the vestibule is the alveolar mucosaThe zone adjacent to the teeth is the gingiva.

The alveolar mucosa and gingiva are separated from each other by a sharp scalloped line which parallels the free margin of the gingiva, themucogingival junction.

 

  • The gingiva is subdivided into the attached and the free gingiva. The free gingiva extends into the interdental spaces as the gingival papilla and ends in a knifelike edge closely adapted to the teeth circumferentially.
  • The gingival sulcus is the crevice between the free marginal gingiva and the point of attachment to the teeth at or near the cemento-enamel junction.

Hard and soft palate

 Space The roof of the oral cavity proper is formed by the hard palate anteriorly and the soft palateposteriorly.

The hard palate extends peripherally to become the palatal gingiva. At the posterior end of the hard palate, there are frequently two small depressions, the fovea palatinaeThe hard palateterminates at an imaginary line running through, or close to the fovea palatinae.

In the midline there is a narrow elevated ridge, the palatine rapheIt extends from a small projection, theincisive papilla posteriorly over the entire length of the hard palate.

On the anterior hard palate radiating from the incisive papilla and anterior portions of the palatine raphe are irregular branching ridges termed the palatine rugaeThe mucous membrane covering the anterior hard palate is keratinized and firmly attached to the underlying bone and therefore is not movable. The peripheral zone is firm but more resilient toward the gingiva.

On the posterior hard palate, the lateral portions between the palatine raphe and the gingiva containnumerous mucous glands, nerves, and blood vessels in the submucosa. This area may be soft to palpation due to the fat and mucous glands.

Posterior to the last molar tooth the hard palate mucosa fuses peripherally with the vestibular gingiva and posteriorly with the pterygomandibular raphe. This prominent ridge is the alveolar tuberosity. The concavity distal to the tuberosity is the hamular notch.

The soft palate begins posteriorly to the imaginary line running laterally near the fovea palatinae. It is a thick fold of mucous membrane which extends posteriorly and downward to end as the uvulaThis fold of mucous membrane provides and important boundary between the oral cavity, the nasal cavity, and the oropharynx.Laterally, the soft palate extends downward to fuse with the pillars of the fauces.

The soft palate mucosa is thin and nonkeratinized. The prominent vascularity gives a slightly darker red color than the hard palate. The smooth texture may be interspersed with prominent ductal orifices from the mucous glands.

Oropharynx and pharynx

Doorway The junction between the mouth and theoropharynx is a narrow passageway bounded above by the soft palate, laterally by the anterior and posterior pillars of the fauces, and below by the tongue.

The pillars of the fauces are two vertically directed projections which descend from the soft palate. The anterior pillar is the glossopalatine arch and the posterior pillar of the pharyngopalatine arch. These arches form a somewhat triangular space between them called the tonsillar niche or tonsillar fold, which contains the palatine tonsils. The anterior pillar ends at the lateral part of the base of the tongue. The posterior pillar gradually flattens out on the lateral wall of the pharynx.

  • The pharynx is a mucous-membrane lined tubular space subdivided for descriptive purposes into three parts. From above downward, these are the nasopharynx the oropharynx and the laryngopharynx.
  • The pharynx consists of a posterior wall and two lateral walls all of which are continuous and fuse anteriorly on each side with the posterior pillars of the fauces.
  • The mucosal surface of the fauces and oropharynx is normally moist. The vascularity may be very prominent and vascular dilation can influence the degree of redness of this area.
  • The soft, smooth surface mucosa may show small elevated aggregates of lymphoid tissue scattered randomly over the oropharynx.

The tongue

 Sea The tongue is a mobile, muscular organ attached with its base and central part of its body to the floor of the mouth. The body of the tongue makes up the horizontal anterior two thirds of the organ. It has two surfaces, the dorsal or dorsum being the superior surface and the ventral being the inferior surface.

The base and body are separated by a shallow V-shaped groove, the terminal sulcus which varies in prominence among individuals.

The dorsum is marked by a slight midline groove, the median sulcusThis runs from the anterior end to a depression near the apex of the terminal sulcus, the foramen cecum.

 

The mucosa of the dorsum forms numerous small elevations called papillaegiving the tongue a very characteristic, roughened surface. There are four types of papillae, the filiform, the fungiform, the foliateand the circumvallate.

  • The filiform papillae are the most numerous and these are slenderconical structures, pink in color, that cover the dorsal surface. The degree of keratinization of the many filiform papillae and the presence of chromogenic bacteria are the major causes of color variation on the dorsal surface.
  • The fungiform papillae are less numerous but are scattered widely along the sides and at the apex of the tongue. They are shaped like small mushrooms with a rounded surface and deeper red color than the filiform papillae.
  • The circumvallate papillae are the largest, but fewest in number, and are prominent due to their deep red color. They form a V-shaped line just anterior and parallel to the terminal sulcus.
  • At the posterior part of the lateral border, there may be irregular, elevated folds of mucosa, the foliate papillaeThe prominence of these structures exhibit a wide range of variation from one individual to another.

The base or root of the tongue makes up the posterior one-third and is the more fixed, vertical part of the organ. It is more closely associated with the oropharynx than with the oral cavity proper. The mucous membrane covering the base is thick and presents an irregular, rough surface due to underlying prominences of lymphoid tissue.

The ventral surface is smooth with a thin mucous membrane, tightly adherent to the tongue musculature. The mucosal surface reflects onto the floor of the mouth. In the midline, there is a distinct, elevated mucosal fold, call the lingual frenum which attaches the free portion of the tongue to the floor of the mouth. The normal color varies from pink to red. There may be large, prominent veins on this surface which will cause a bluish color.

The sides or lateral margins of the tongue are outlined separately because there are a relatively significant number of diagnoses that only occur in this location. This area is approximately one centimeter wide along the anterior two thirds of the tongue. On the lateral borders, there is usually a sharp contrast to both texture and color where the dorsum and ventral surface merge. There is a deeper red as the papillae end and the smooth ventral surface begins.

Floor of the mouth

 Space The inferior boundary of the oral cavity proper is thefloor of the mouth.

When the tongue is elevated, there is a U-shaped space which extends, laterally and anteriorly from the tongue to the alveolar mucosa of the mandible. This represents the floor of the mouth.
  • The mucosa is nonkeratinized, soft, and smooth except for the sublingual ridges.
  • The vascular network may vary in prominence.
 Doorway  A number of important anatomic structures are located beneath the surface in the lateral spaces formed by the lingual frenulum.

Each of these lateral spaces contains thegenioglossus and geniohyoid muscles the sublingual glandand its ducts.

These lateral spaces also contain the upper portion of the submandibular glands and their ducts, nerves, lymph nodes, and abundant fat tissue.

The underlying important structures influence the surface features of the floor mucosa. The sublingual glands and the ducts of the submandibular glands cause bilateral elevations close to the lingual frenulum which are called the sublingual folds or ridges.

Each sublingual fold ends anteriorly in a small round papilla called the sublingual caruncleThese caruncles contain openings for the flow of secretions of the submandibular and sublingual glands.

This concludes the normal oral soft tissues that the dentist is expected to include in an oral examination. This information will help you locate and describe accurately any abnormal change found during an examination.