DH133 Dental Anatomy PDF

DH133 Dental Anatomy The Oral Cavity Facilitated by: Engy Saad, RDH, ACE, BDD 1  Oral Cavity Learning outcomes: 1. To describe the boundaries and subboundaries of the oral cavity and the structures in each area. 2. To...

DH133 Dental Anatomy The Oral Cavity Facilitated by: Engy Saad, RDH, ACE, BDD 1  Oral Cavity Learning outcomes: 1. To describe the boundaries and subboundaries of the oral cavity and the structures in each area. 2. To define the terms vestibule, oral cavity proper, mucobuccal fold, frenum, alveolar mucosa, gingiva, exostoses, torus palatinus, and torus mandibularis. 3. To define the landmarks in the floor of the mouth and the hard and soft palate and the structures that form them. 4. To differentiate normal from abnormal anatomy in the oral cavity and to ensure a follow-up examination. Copyright © 2019 by Elsevier, Inc. All rights reserved. 2  Oral Cavity Properties A dental professional must be totally committed to improving the oral health for every patient. In order to accomplish this, dental professionals must be particularly knowledgeable about their main area of focus, the oral cavity, and the adjacent throat or pharynx. To visualize this area of focus successfully, it is important to know the boundaries, terminology, and divisions of the oral cavity and pharynx. 3  Oral Cavity Properties A certain degree of variation can be possible in the oral cavity and visible divisions of the pharynx. However, a change in any tissue or associated structure in a patient may signal a condition of clinical significance and must be noted in the patient record as well as correctly followed up by the examining dental professional. Thus, it is not the variations among individuals that should be noted but the changes in a particular individual. 4  Oral Cavity Properties The illustrations of the oral cavity and pharynx as well as any structures associated with them are oriented to show the head in anatomic position, unless otherwise noted. This is the same as if the patient were being viewed straight on while sitting upright in the dental chair. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed., St Louis, Saunders, 2017.) 5  Oral Cavity The oral cavity is at the upper end of the digestive system and at its posterior end forms a common pathway with the respiratory system. It starts at the lips and extends to the area posterior to the palatine tonsils and includes the area from the floor of the mouth upward to the hard and soft palate. 6  Oral Cavity Divisions The Oral cavity divided into: 1. Vestibule Space between lips or cheeks and teeth 2. Oral cavity proper Area surrounded by teeth or alveolar ridges back to palatine tonsils. Includes region from the floor of mouth upward to hard and soft palates 7 Oral Cavity Divisions The lips of the face mark the anterior boundary of the oral cavity, and the throat (or pharynx) is the posterior boundary. The cheeks of the face mark the lateral boundaries, and the palate marks the superior boundary. The floor of the mouth is the inferior border of the oral cavity. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 8 Oral Cavity Divisions Vestibule: Lips—junction between skin of the face and mucosa of the oral cavity Vermilion zone—a transitional zone of reddish tissue between these two areas Philtrum—indentation at midline on skin of the upper lip, derived from the embryonic medial nasal processes 9 Oral Cavity Divisions Vestibule: Vestibular anterior border – The lips (labial) Vestibular lateral border – The cheeks (buccal) Vestibular posterior border – The anterior border of the ramus of the mandible covered with soft tissue Cheek is formed largely by buccinator muscle, covered with https://semmelweis.hu/anatomia/files/2019/ 02/Oral-cavity-Shahbazi-2019.02.07.pdf skin on the outside and mucous membrane on the inside. 10 Oral Cavity Divisions Vestibule: Anterior and Posterior Borders Buccinator muscle extends back from the corners of the mouth to join with muscles of upper throat wall. Crosses in front of the mandibular ramus from lateral position to medial position Zygomaticoalveolar crest—ridge of bone at the upper posterior https://semmelweis.hu/anatomia/files/2019/ vestibular space; beginning of the 02/Oral-cavity-Shahbazi-2019.02.07.pdf anterior part of the zygomatic arch (cheekbone) 11 Oral Cavity Divisions Those structures closest to the facial surface are facial. Those facial structures closest to the lips are labial. Those facial structures close to the inner cheek are buccal. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 12 Oral Cavity Divisions Those structures closest to the tongue are lingual. Those lingual structures closest to the palate are palatal. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 13  Oral Vestibules The upper and lower horseshoe-shaped spaces in the oral cavity between the lips and cheeks anteriorly and laterally and the teeth and their soft tissue medially and posteriorly are considered the vestibules, having both a maxillary and mandibular vestibule. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 14 Oral Vestibules These oral vestibules are lined by a mucous membrane or oral mucosa. The inner parts of the lips are lined by a pinkish labial mucosa. The labial mucosa is continuous with the equally pinkish buccal mucosa that lines the inner cheek. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 15 Oral Vestibules The buccal mucosa covers a dense pad of underlying fat tissue at the posterior part of each vestibule, the buccal fat pad. The buccal fat pad acts as a protective cushion during mastication or chewing. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 16 Oral Vestibules On the inner part of the buccal mucosa, just opposite the maxillary second molar, is a small elevation of tissue called the parotid papilla. The parotid papilla protects the opening of the parotid duct (or Stensen duct) of the parotid salivary gland.. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 17 Oral Vestibules Mucobuccal or mucolabial fold—mucosa of the lips or cheeks that turns toward the gingival tissue Alveolar mucosa—movable mucosa lying against alveolar bone. Generally reddish in color due to blood vessels underneath thin mucosa Mucogingival junction—where alveolar mucosa becomes tightly attached to bone; beginning of gingiva (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 18  Oral Vestibules The labial frenum is a fold of tissue located at the midline between the labial mucosa and the alveolar mucosa on the upper and lower dental arches. Upper frenum is usually more pronounced than the lower. Attachment of the maxillary frenum may extend to crest of the alveolar ridge or over it. 19 Oral Vestibules Diastema—when maxillary frenum is so firmly attached that erupting central incisors may be pushed slightly aside, creating a space between them Gingival recession caused by mandibular labial frenum extending too close to gingiva and pulling downward on the tissue 20 Clinical Considerations with Oral Mucosa: Fordyce Granules On the surface of the labial and buccal mucosa is a common variation, Fordyce spots (or granules). These are visible as small yellowish elevations on the oral mucosa. They represent deeper deposits of sebum from trapped or misplaced sebaceous gland tissue, usually associated with hair follicles in other regions but not here. They are visible on the labial skin (Courtesy of Margaret J. Fehrenbach, RDH, MS.) as well 21 Linea Alba Another variation noted on the buccal mucosa is the linea alba. This is a white ridge of calloused tissue (or hyperkeratinization) that extends horizontally at the level where the maxillary and mandibular teeth come together and Fig. 2.3, B occlude (considered the occlusal plane). (Courtesy of Margaret J. Fehrenbach, RDH, MS.) 22 Jaws, Alveolar Processes, and Teeth The jaws, the maxilla and mandible, are deep to the lips and within the oral cavity. Fig. 1.7 (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 23 Jaws, Alveolar Processes, and Teeth The maxilla has a nonmovable articulation with many facial and skull bones, and each maxillary bone includes a body and four processes. Each body of the maxilla is superior to the teeth and contains the maxillary sinus. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 24 Jaws, Alveolar Processes, and Teeth In contrast, the mandible is a single bone with a movable articulation with the temporal bones at each temporomandibular joint (TMJ). The heavy horizontal part of the lower jaw inferior to the teeth is the body of the mandible. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 25 Jaws, Alveolar Processes, and Teeth The alveolar process or alveolar bone is the bony extension for both the maxilla and mandible that contain each tooth socket of the teeth or alveolus. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 26 Jaws, Alveolar Processes, and Teeth All the teeth are attached to the bony surface of the alveoli by the fibrous periodontal ligament (PDL), which allows some slight tooth movement within the alveolus while still supporting the tooth. 27 Jaws, Alveolar Processes, and Teeth Each of the mature and fully erupted teeth consists of both the crown and the root(s). The crown of the tooth is composed of the extremely hard outer enamel layer and the moderately hard inner dentin layer overlying the pulp of the tooth. The pulp is the soft innermost layer in the tooth. (From Nanci A: Ten Cate’s oral histology, 9th ed, St. Louis, 2018, Mosby, 2018.) 28 Jaws, Alveolar Processes, and Teeth The dentin layer continues to cover the soft tissue of the pulp of the tooth in the root(s), but the outermost layer of the root(s) is composed of cementum. 29 Dental Arches The alveolar processes with the teeth in the alveoli are also considered dental arches of which there are two: the maxillary arch and the mandibular arch. The teeth in the maxillary arch are the maxillary teeth, and the teeth in the mandibular arch are the mandibular teeth. 30 Dental Arches Just distal to the last tooth of the maxillary arch is a tissue-covered elevation of the bone, the maxillary tuberosity. Similarly, on the lower jaw is a dense pad of tissue located just distal to the last tooth of the mandibular arch, the retromolar pad. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 31 Dental Arches The tooth types in both arches of the teeth of children or primary teeth include incisors, canines, and molars. Adult teeth or permanent teeth also include all the same tooth types as the primary teeth as well as premolars. 32 Dental Arches The teeth in the front of the mouth, the incisors and canines, are considered anterior teeth. The teeth located toward the back of the mouth, the molars and premolars, if present, are considered posterior teeth. 33 Clinical Considerations with Alveolar Process: Exostoses A less than common variation present usually on the facial surface of the alveolar process of the maxillary arch is exostoses. They are localized developmental growths of bone covered in oral mucosa with a possible hereditary etiology and which may be associated with occlusal trauma. They may be single or multiple and unilateral or bilateral raised hard areas located in the premolar to molar region covered by oral mucosa. They appear on radiographs as radiopaque (light) areas. 34 Exostoses Fig. 2.7 (Courtesy of Margaret J. Fehrenbach, RDH, MS.) 35 Mandibular Tori Another similar variation present on the lingual surface of the mandibular arch is the mandibular torus. Each torus is a developmental growth of bone with a possible hereditary etiology similar to exostoses and may also be associated with grinding, which is Fig. 2.8 considered bruxism. (Courtesy of Margaret J. Fehrenbach, RDH, MS.) 36  Gingival Tissue Surrounding the maxillary and mandibular teeth in the alveoli and covering the alveolar processes are the soft tissue gums or gingiva, which is composed of a firm pink oral mucosa. Fig. 2.9 (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 37 Gingival Tissue The gingival tissue that tightly adheres to the alveolar process surrounding the roots of the teeth is the attached gingiva. The line of demarcation between the firmer and pinker attached gingiva and the movable and redder alveolar mucosa that lines the vestibules is the scallop-shaped mucogingival junction. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 38 Gingival Tissue At the gingival margin of each tooth is the marginal gingiva (or free gingiva), which forms a cuff above the neck of the tooth. The free gingival groove separates the marginal gingiva from the attached gingiva. At the most coronal part of the marginal gingiva Fig. 10.1 is the free gingival crest. 39 Gingival Tissue The interdental gingiva is the gingival tissue between adjacent teeth adjoining the attached gingiva, with each individual extension being an interdental (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, ed 5, St Louis, 2017, Saunders/Elsevier.) papilla. 40 Gingival Tissue The attached gingiva may have areas of melanin pigmentation, especially at the base of each interdental papillae. (Courtesy of Margaret J. Fehrenbach, RDH, MS.) 41 Gingival Tissue The circular inner surface of the gingival tissue of each tooth faces an equally rounded space, the gingival sulcus. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 42  Oral Cavity Proper The inside of the mouth is known as the oral cavity proper. The space of the oral cavity is enclosed anteriorly by both the maxillary arch and mandibular arch. Posteriorly, the opening from the oral cavity proper into the pharynx or throat is the fauces. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 43 Oral Cavity Proper The fauces are formed laterally on each side by the anterior faucial pillar and the posterior faucial pillar. The palatine tonsils are located between these folds of tissue created by underlying muscles. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 44 Oral Cavity Proper (Courtesy of Margaret J. Fehrenbach, RDH, MS.) 45 Palate Within the oral cavity proper is the roof of the mouth or palate. The palate separates the oral cavity from the nasal cavity. The bony whiter anterior arched part is the hard palate. 46 Palate Incisive papilla A small bulge of tissue at the most anterior part of the hard palate, lingual to the anterior teeth, is the incisive papilla. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 47 Palate Palatine rugae Directly posterior to the incisive papilla are palatine rugae, which are firm irregular ridges of tissue radiating from the incisive papilla and raphe. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 48 Palate Incisive Foramen Beneath this papilla is the incisive foramen It carries the nasopalatine nerves, and blood vessels, to the mucous membrane lingual to the maxillary incisor teeth. This is a point of injection for anesthetizing the anterior palate area between the canines or cuspids. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 49 Palate The yellower, looser, and softer posterior part of the palate is considered the soft palate. A midline muscular structure, the uvula of the palate, hangs down from the posterior margin of the soft palate. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 50 Palate The midline ridge of tissue that runs the full length of the palate from the incisive papilla to the uvula is the median palatine raphe, which overlies the bony fusion of the palate. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 51 Palate The pterygomandibular fold also extends from the junction of hard and soft palates down to the mandible, just posterior to the most distal mandibular tooth, and stretches when (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) the mouth is opened wider. 52 Clinical Consideration with Palate: Palatal Torus A less than common variation noted on the midline of the hard palate is the palatal torus, which is similar to the mandibular tori in presentation and etiology. 53 Tongue The posterior one-third of the tongue is the pharyngeal part or base of the tongue. The anterior two-thirds of the tongue is the oral part or body of the tongue, which lies within the oral cavity proper. The tip of the tongue is the apex of the tongue. Fig. 2.14 (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 54 Tongue The top or dorsal surface of the tongue has a midline depression, the median lingual sulcus. Certain surfaces of the tongue have small, elevated structures of specialized mucosa, the lingual papillae, some of which are associated with taste buds. Fig. 2.14 (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 55 Tongue The slender threadlike whitish lingual papillae are the filiform lingual papillae, which give the dorsal surface its velvety texture. They are the most abundant papillae. They do not have taste buds. The reddish small mushroom-shaped dots on the dorsal surface are the fungiform lingual papillae (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 56 Tongue The 10 to 14 larger mushroom-shaped lingual papillae with taste buds, the circumvallate lingual papillae, line up along the anterior side of the sulcus terminalis on the body. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 57 Tongue Farther posteriorly on the dorsal surface of the tongue and more difficult to see clinically is an inverted V-shaped groove, the sulcus terminalis. It separates the base from the body of the tongue. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 58 Tongue Where the sulcus terminalis points backward toward the throat or pharynx is a small, pitlike depression, the foramen cecum. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 59 Tongue Even farther posteriorly on the dorsal surface of the base of the tongue is an irregular mass of tissue, the lingual tonsil. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 60 Tongue The side or lateral surface of the tongue has vertical ridges, the foliate lingual papillae. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 61 Tongue The underside or ventral surface of the tongue has large visible blood vessels, the deep lingual veins, which pass close to the surface. Lateral to each deep lingual vein is the plica fimbriata with fringelike projections. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 62 Clinical Considerations for Tongue: Enlarged Lingual Tonsil 63 Enlarged Lingual Tonsil The lingual tonsils are rounded masses of lymphatic tissue that cover the posterior region of the tongue located on the dorsal surface at the base of the tongue. The cause of enlargement (lymphadenopathy) of the lingual tonsils is most likely a chronic, low-grade infection of the tonsil. It can be asymptomatic, but can be associated with vague symptoms, including sore throat, dysphagia, snoring, globus sensation, and obstructive sleep apnea; a nonproductive chronic cough caused by irritation of the pharynx by the lingual tonsils may occur. 64 Floor of the Mouth The floor of the mouth is located in the oral cavity proper, inferior to the ventral surface of the tongue. The lingual frenum is an anterior midline fold of tissue between the ventral surface of the tongue and the floor of the mouth. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 65 Floor of the Mouth A ridge of tissue on each side of the floor of the mouth, the sublingual fold, joins in a V-shaped configuration extending from the lingual frenum to the base of the tongue. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 66 Floor of the Mouth The small papilla or sublingual caruncle at the anterior end of each sublingual fold contains openings of the submandibular duct (Wharton duct) and sublingual duct (Bartholin duct) from both the sublingual as well as the submandibular salivary gland. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 67 Floor of the Mouth The sublingual folds represent the underlying sublingual salivary gland and contain openings of its sublingual duct. (From Fehrenbach MJ, Herring SW: Illustrated anatomy of the head and neck, 5th ed,, St Louis, Saunders, 2017.) 68  Pharyngeal Divisions The oral cavity proper provides the entrance into the deeper structure of the throat or pharynx. The pharynx is a muscular tube that has both respiratory and digestive system functions. The pharynx has three divisions, the nasopharynx, oropharynx, and laryngopharynx. 69 Pharyngeal Divisions The division of the pharynx that is superior to the level of the soft palate is the nasopharynx, which is continuous with the nasal cavity. The division that is between the soft palate and the opening of the larynx is the oropharynx, which is the oral part of the pharynx. Finally, the laryngopharynx is the more inferior division of the pharynx, close to the laryngeal opening 70 71