1. Anatomy of the Oral Cavity Ass.Prof. Dr. Saif Ali Ahmed Ghabisha

2. Oral Region The oral region includes the oral cavity, teeth, gingivae, tongue, palate, and the region of the palatine tonsils. The oral cavity is where food is ingested and prepared for digestion in the stomach and small intestine. Food is chewed by the teeth, and saliva from the salivary glands facilitates the formation of a manageable food bolus. Deglutition (swallowing) is voluntarily initiated in the oral cavity. The voluntary phase of the process pushes the bolus from the oral cavity into the pharynx, the expanded part of the alimentary (digestive) system, where the automatic phase of swallowing occurs.

3. Oral Cavity The oral cavity consists of two parts: the oral vestibule and the oral cavity proper. It is in the oral cavity that food and drinks are tasted and savored and where mastication and lingual manipulation of food occur.

4. The oral vestibule is the slit-like space between the teeth and buccal gingiva and the lips and cheeks. The vestibule communicates with the exterior through the mouth. Oral Cavity

5. The oral cavity proper is the space between the upper and the lower dental arches (maxillary and mandibular alveolar arches and the teeth they bear). It is limited laterally and anteriorly by the maxillary and mandibular alveolar arches housing the teeth. The roof of the oral cavity is formed by the palate. Posteriorly, the oral cavity communicates with the oropharynx (oral part of the pharynx). When the mouth is closed and at rest, the oral cavity is fully occupied by the tongue. Oral Cavity

6. The size of the oral fissure (rima oris - the oral opening) is controlled by the circumoral muscles, such as the orbicularis oris (the sphincter of the oral fissure), the buccinator, risorius, and depressors and elevators of the lips (dilators of the fissure). Oral Cavity

7. Oral Cavity (Mouth) The parotid duct opens at the vestibule of mouth opposite upper 2 nd molar tooth. Sublingual Region : lies in the floor of mouth below tongue, contains: 1.The frenulum of the tongue is a fold of mucous membrane in the midline connects undersurface of tongue to floor of mouth. 2.Duct of submandibular gland opens on each side of frenulum. 3.Sublingual gland is covered by m.m called sublingual fold, which extends laterally on both sides from lower part of frenulum, and sublingual ducts open by many apertures on its summit.

8. Oral Cavity (Mouth)

9. gums and teeth Front of the mouth cavity proper

10. Gingivae (gums): are composed of fibrous tissue covered with mucous membrane. The gingiva proper (attached gingiva) is firmly attached to the alveolar processes of the jaws and the necks of the teeth The gingiva proper is normally pink, stippled, and keratinizing. The alveolar mucosa (unattached gingiva) is normally shiny red and non- keratinizing. Front of the mouth cavity proper gums and teeth

11. Primary (deciduous) Secondary (permanent ) Dentition (teeth): There are two Dentitions Front of the mouth cavity proper

12. Dentition (teeth): There are two dentitions Primary (deciduous) Consist of 20 teeth Begin to form during the first trimester of pregnancy Typically begin erupting around 6 months Most children have a complete primary dentition by 3 years of age gums and teeth

13. Dentition (teeth): There are two dentitions Secondary (permanent) Consist of 32 teeth in most cases Begin to erupt around 6 years of age Most permanent teeth have erupted by age 12. Third molars (wisdom teeth) are the exception; often do not appear until late teens or early 20s

14. gums and teeth Classification of Teeth: Incisors (central and lateral) Canines (cuspids) Premolars (bicuspids) Molars Identifying Teeth Incisor Canine Premolar Molar

15. Identifying Teeth Incisor Canine Premolar Molar Incisors function as cutting or shearing instruments for food. Canines possess the longest roots of all teeth and are located at the corners of the dental arch. Premolars act like the canines in the tearing of food and are similar to molars in the grinding of food. Molars are located nearest the temporomandibular joint (TMJ), which serves as the fulcrum during function. gums and teeth

16. Apical Labial Lingual Distal Mesial Incisal Teeth: Identification Tooth Surfaces Labial Apical Lingual Distal Apical Mesial Incisal

17. Enamel Alveolar Bone Pulp Chamber gums and teeth Enamel (hard tissue) Dentin (hard tissue) Odontoblast Layer Pulp Chamber (soft tissue) Gingiva (soft tissue) Periodontal Ligament (soft tissue) Cementum (hard tissue) Alveolar Bone (hard tissue) Pulp Canals Apical Foramen The Dental Tissues: Dentin Odontoblast Layer Gingiva Periodontal Ligament Cementum Pulp Canals Apical Foramen Anatomic Crown Anatomic Root

18. The roof of the mouth is formed by the hard palate in front and the soft palate behind. Roof of Mouth

19. Palate hard soft palate  Lies in the roof of the oral cavity  Has two parts: Hard (bony) palate anteriorly Soft (muscular) palate posteriorly

20. Hard Palate  Lies in the roof of the oral cavity.  Forms the floor of the nasal cavity.  Formed by: –Palatine processes of maxillae in front. –Horizontal plates of palatine bones behind. Bounded by alveolar arches.

21.  Posteriorly, continuous with soft palate  Its undersurface covered by mucoperiosteum  Shows transverse ridges in the anterior parts Hard Palate

22. Soft Palate  Attached to the posterior border of the hard palate  Covered on its upper and lower surfaces by mucous membrane  Composed of: –Muscle fibers –An aponeurosis –Lymphoid tissue –Glands –Blood vessels –Nerves

23. Palatine Aponeurosis  Fibrous sheath  Attached to posterior border of hard palate.  Is expanded tendon of tensor velli palatini.  Splits to enclose musculus uvulae.  Gives origin & insertion to palatine muscles.

24. Muscles  Tensor veli palatini –Origin: spine of sphenoid; auditory tube –Insertion: forms palatine aponeurosis –Action: Tenses soft palate Levator veli palatini –Origin:petrous temporal bone, auditory tube, palatine aponeurosis –Insertion: palatine aponeurosis –Action: Raises soft palate Musculus uvulae –Origin: posterior border of hard palate –Insertion: mucosa of uvula – Action: Elevates uvula

25. Muscles Palatoglossus –Origin: palatine aponeurosis. –Insertion: side of tongue. –Action: pulls root of tongue upward, narrowing oropharyngeal isthmus. Palatopharyngeus –Origin: palatine aponeurosis –Insertion: posterior border of thyroid cartilage. –Action: Elevates wall of the pharynx.

26. Sensory Nerve Supply Mostly by the maxillary nerve through its branches: –Greater palatine nerve –Lesser palatine nerve –Nasopalatine nerve Glossopharyngeal nerve supplies the region of the soft palate

27. Motor Nerve Supply All the muscles, except tensor veli palatini, are supplied by the: –Pharyngeal plexus. Tensor veli palatini supplied by the: –Nerve to medial pterygoid, a branch of the mandibular division of the trigeminal nerve.

28. Blood Supply Branches of the maxillary artery: –Greater palatine –Lesser palatine –Sphenopalatine Ascending palatine, branch of the facial artery Ascending pharyngeal, branch of the external carotid artery

29. Tongue The tongue (L. lingua; G. glossa) is a mobile muscular organ that can assume a variety of shapes and positions. It is partly in the oral cavity and partly in the oropharynx. The tongue is involved with mastication, taste, deglutition (swallowing), articulation, and oral cleansing; however, its main functions are forming words during speaking and squeezing food into the oropharynx when swallowing.

30. Taste Functions The tonge is the most important articulator for speech production. During speech, the tongue can make amazing range of movements The primary function of the tongue is to provide a mechanism for taste. Taste buds are located on different areas of the tongue, but are generally found around the edges. They are sensitive to four main tastes: Bitter, Sour, Salty & Sweet

31. Parts and Surfaces of the Tongue The tongue has a root, a body, an apex, a curved dorsum, and an inferior surface. The root of the tongue is the part of the tongue that rests on the floor of the mouth. It is usually defined as the posterior third of the tongue.

32. The body of the tongue is the anterior two thirds of the tongue. The apex (tip) of the tongue is the anterior end of the body, which rests against the incisor teeth. The body and apex of the tongue are extremely mobile. Parts and Surfaces of the Tongue

33. The dorsum (dorsal surface) of the tongue is the posterosuperior surface, which is located partly in the oral cavity and partly in the oropharynx. It is characterized by a V-shaped groove, the terminal sulcus or groove (sulcus terminalis), the angle of which points posteriorly to the foramen cecum small pit, frequently absent, is the non- functional remnant of the proximal part of the embryonic thyroglossal duct from which the thyroid gland developed. Parts and Surfaces of the Tongue

34. The terminal sulcus divides the dorsum of the tongue into the anterior (oral) part in the oral cavity proper and the posterior (pharyngeal) part in the oropharynx. The margin of the tongue is related on each side to the lingual gingivae and lateral teeth. The mucous membrane on the anterior part of the tongue is rough because of the presence of numerous small lingual papillae (4 types). Parts and Surfaces of the Tongue

35. Dorsal Surface Anterior two third: mucosa is rough, shows four types of papillae:  Filliform  Fungiform  Vallate  Foliate  Posterior one third: No papillae but shows nodular surface because of underlying lymphatic nodules, the lingual tonsils.

36. The mucous membrane over the anterior part of the dorsum of the tongue is thin and closely attached to the underlying muscle. A shallow midline groove of the tongue divides the tongue into right and left halves. The groove also indicates the site of fusion of the embryonic distal tongue buds. Groove of the tongue

37. Ventral Surface  Smooth (no papillae)  In the midline anteriorly, a mucosal fold, frenulum connects the tongue with the floor of the mouth  Lateral to frenulum, deep lingual vein can be seen through the mucosa  Lateral to lingual vein, a fold of mucosa forms the plica fimbriata

38. Inferior surface of the tongue

39. Muscles of the Tongue The tongue is essentially a mass of muscles that is mostly covered by mucous membrane. The muscles of the tongue do not act in isolation and some muscles perform multiple actions; parts of a single muscle are capable of acting independently, producing different, even antagonistic actions. In general, however, extrinsic muscles alter the position of the tongue while intrinsic muscles alter its shape. The four intrinsic and four extrinsic muscles in each half of the tongue are separated by a median fibrous lingual septum, which merges posteriorly with the lingual aponeurosis.

40. Extrinsic Muscles of the Tongue palatoglossus styloglossus hyoglossus genioglossus Muscles of the Tongue

41. 41 MuscleShape and Position Proximal AttachmentDistal AttachmentMain Action(s) Extrinsic muscles of the tongue Genioglossus Fan-shaped muscle; constitutes bulk of tongue Via a short tendon from superior part of mental spine of mandible Entire dorsum of tongue; inferior most and posterior most fibers attach to body of hyoid bone Bilateral activity depresses tongue, especially central part, creating a longitudinal furrow; posterior part pulls tongue anteriorly for protrusion; most anterior part retracts apex of protruded tongue; unilateral contraction deviates (wags) tongue to contralateral side CNXII Muscles of the Tongue

42. Muscle Shape and Position Proximal AttachmentDistal AttachmentMain Action(s) Extrinsic muscles of the tongue HyoglossusThin, quadrilateral muscle Body and greater horn of hyoid bone Inferior aspects of lateral part of tongue Depresses tongue, especially pulling its sides inferiorly; helps shorten (retrude) tongue CNXII Muscles of the Tongue

43. Muscle Shape and Position Proximal AttachmentDistal AttachmentMain Action(s) Extrinsic muscles of the tongue StyloglossusSmall, short triangular muscle Anterior border of distal styloid process; stylohyoid ligament Sides of tongue posteriorly, interdigitating with hyoglossus Retrudes tongue and curls (elevates) its sides, working with genioglossus to form a central trough during swallowing PalatoglossusNarrow crescent- shaped palatine muscle; forms posterior column of isthmus of fauces Palatine aponeurosis of soft palate Enters posterolateral tongue transversely, blending with intrinsic transverse muscles Capable of elevating posterior tongue or depressing soft palate; most commonly acts to constrict isthmus of fauces CNXII CNX Muscles of the Tongue

44. Intrinsic Muscles of the Tongue –The superior and inferior longitudinal –transverse –vertical muscles They have their attachments entirely within the tongue and are not attached to bone The superior and inferior longitudinal muscles act together to make the tongue short and thick and to retract the protruded tongue The transverse and vertical muscles act simultaneously to make the tongue long and narrow, which may push the tongue against the incisor teeth or protrude the tongue from the open mouth (especially when acting with the posterior inferior part of the genioglossus). Innervation is CN XII Muscles of the Tongue

46. Innervation of the Tongue All muscles of the tongue, receive motor innervation from CN XII, the hypoglossal nerve, except the palatoglossus m. (CN X, vagus nerve)

47. Sensory Nerve Supply  Anterior ⅔: –General sensations: Lingual nerve –Special sensations : chorda tympani  Posterior ⅓: –General & special sensations: glossopharyngeal nerve  Base: –General & special sensations: internal laryngeal nerve

48. Motor Nerve Supply  Intrinsic muscles:  Hypoglossal nerve  Extrinsic muscles:  All supplied by the hypoglossal nerve, except the palatoglossus  The palatoglossus supplied by the pharyngeal plexus

49. Innervation of the Tongue

50. Blood Supply Arteries:  Lingual artery  Tonsillar branch of facial artery  Ascending pharyngeal artery Veins:  Lingual vein, ultimately drains into the internal jugular vein Hypoglossal nerve Lingual artery & vein Deep lingual vein Dorsal lingual artery & vein

51. Blood Supply

52. Lymphatic Drainage Tip: –Submental nodes bilaterally & then deep cervical nodes. Anterior two third: –Submandibular unilaterally & then deep cervical nodes. Posterior third: –Deep cervical nodes (jugulodigastric mainly).

53. Salivary Glands

54. Salivary glands: are composed of 6 major glands, in addition to minor glands. Major: 2 parotid glands. 2submandibular g. 2 Sublingual g. Minor: Multiple minor glands Salivary glands

55. About 450 lie under the mucosa They are distirbuted in the mucosa of the lips, cheeks, palate, floor of mouth & retromolar area Also appear in oropharyanx, larynx & trachea MINOR SALIVARY GLAND

56. THE PAROTID REGION

57. It includes: The parotid salivary gland The structures related to the gland

58. THE PAROTID GLAND

59. It is the largest of the salivary glands and it has pyramidal shape. It lies below the auricle, occupying the region between ramus of mandible & mastoid process. EXTENT: Superiorly: to zygomatic arch. Inferiorly: to angle of mandible. Anteriorly: to overlap posterior border of masseter. Posteriorly: to overlap anterior border of sternomastoid.

60. THE PAROTID GLAND SUBDIVISIONS: Main gland. Accessory gland: above parotid duct. CAPSULE: Derived from deep fascia of neck (cervical fascia). Its superficial layer is attached to zygomatic arch & extends to cover masseter. Its deep layer is attached to mandible, styloid & mastoid processes. A thickening of deep fascia extends from styloid process to angle of mandible (stylomandibular ligament) & separates the capsule of parotid from that of submandibular gland. It is tense (swellings of parotid gland are painful).

61. THE PAROTID GLAND RELATIONS: Superficial: skin, superficial fascia, great auricular nerve, superficial parotid (preauricular) lymph nodes. Anteromedial: posterior border of ramus of mandible + muscles attached to ramus (masseter, medial pteygoid). Posteromedial: mastoid process + muscles attached to it (sternomastoid, posterior belly of digastric), styloid process + muscles attached to it (stylohyoid, styloglossus, stylopharyngeus), carotid sheath & its contents (internal jugular vein, internal carotid artery, 9 th, 10 th, 11 th & 12 th cranial nerves). Medial: pharyngeal wall.

62. RELATIONS THE PAROTID GLAND

63. STRUCTURES WITHIN THE PAROTID GLAND Termination of facial nerve & beginning of its five terminal motor branches : most superficial structures Terminations of superficial temporal & maxillary veins + the whole retromandibular vein + beginning of its two divisions (anterior & posterior) Termination of external carotid artery & beginning of its two terminal branches (superficial temporal & maxillary): deepest structures Deep parotid lymph nodes: embedded within substance of the gland THE PAROTID GLAND

64. STRUCTURES EMERGING FROM THE PAROTID GLAND THE PAROTID GLAND

65. STRUCTURES EMERGING FROM THE PAROTID GLAND

66. PAROTID DUCT

67. LENGTH: Fife cm. COURSE & RELATIONS: Emerges from anterior border of gland. Runs obliquely forwards, superficial to masseter & below transverse facial artery & accessory parotid. TERMINATION: Pierces: buccal pad of fat, buccopharyngeal fascia, buccinator muscle & buccal mucosa Opens: into the vestibule of mouth, opposite the crown of upper 2 nd molar tooth

68. PAROTID DUCT

69. NERVE SUPPLY PARASYMPATHETIC (SECRETORY): Origin: inferior salivary nucleus (medulla) Preganglionic fibers: run along the lesser petrosal nerve (branch of tympanic of glossopharyngeal (9 th cranial). Ganglion: fibers relay in the otic ganglion (infratemporal fossa). Postganglionic fibers: reach the parotid gland along auriculotemporal nerve (branch of mandibular of trigeminal). SYMPATHETIC: Postganglionic sympathetic fibers reach the gland as a plexus around external carotid artery

70. NERVE SUPPLY

71. BLOOD VESSELS and LYMPHATIC DRAINAGE ARTERIES: External carotid VEINS: Retromandibular vein LYMPHATIC DRAINAGE: Into superficial & deep parotid lymph nodes Finally into deep cervical lymph nodes

72. BLOOD VESSELS and LYMPHATIC DRAINAGE

74. SUPRAHYOID MUSCLES DIGASTRIC MUSCLE: Origin: by 2 bellies: 1.Anterior belly: from digastric fossa of mandible 2.Posterior belly: from mastoid notch Insertion: both bellies unite in an intermediate tendon held by a fibrous loop into the hyoid bone Nerve supply: 1.Anterior belly: nerve to myelohyoid 2.Posterior belly: facial nerve

75. SUPERFICIAL RELATIONS OF THE DIGASTRIC 5 muscles, 2 glands, one vein & one bone 1.Platysma. 2.Sternomastoid. 3.Splenius capitis. 4.Longissimus capitis. 5.Parotid gland. 6.Submandibular gland. 7.Stylohyoid. 8.Retromandibular vein. 9.Mastoid process.

76. DEEP RELATIONS Deep to the anterior belly of the digatric is the mylohyoid. Deep to the posterior belly of the digastric are: –Obliques superiorius, –occipital artery, –rectus capitis lateralis, –transverse process of atlas, –accessory nerve, –internal jugular vein, –hypoglossal nerve, –internal and external carotid arteries. –facial and lingual arteries –hyoglossus.

77. SUPRAHYOID MUSCLES STYLOHYOID MUSCLE: Origin: styloid process Insertion: hyoid bone Nerve supply: facial nerve

78. SUPRAHYOID MUSCLES MYELOHYOID MUSCLE: Origin: myelohyoid line of mandible Insertion: the muscles on both sides meet in a median raphe extending from symphysis menti to hyoid bone Nerve supply: nerve to myelohyoid

79. SUPRAHYOID MUSCLES GENIOHYOID MUSCLE: Origin: inferior genial tubercle Insertion: hyoid bone Nerve supply: ventral ramus of C1

80. ACTIONS OF SUPRAHYOID MUSCLES 1.Fixation of hyoid bone (acting with infrahyoid muscles) during movement of tongue. 2.Depression of mandible to assist lateral pterygoid in opening of the mouth 3.Elevation of hyoid bone to elevate the floor of mouth & to improve tongue grip

81. Submandibular Gland

82. It consists of a mixture of serous and mucous acini. It lies beneath the lower border of the body of the mandible. It is divided into superficial and deep parts by the mylohyoid muscle. The deep part of the gland lies beneath the mucous membrane of the floor of the mouth. The submandibular duct emerges from the anterior end of the deep part of the gland & runs forward beneath the mucous membrane of the mouth. The duct opens into the floor of the mouth on a small papilla, which is situated at the side of the frenulum of the tongue. Submandibular Gland

83. Anteriorly:  anterior belly of digastric. Posteriorly:  posterior belly of digastric, stylohyoid & parotid gland. Medially:  mylohyoid,  hyoglossus,  lingual nerve,  submandibular ganglion  hypoglossal nerve. Laterally:  submandibular fossa of the mandible..

84. Anteriorly:  sublingual gland. Posteriorly:  posterior belly of digastric &  stylohyoid,  parotid gland. Medially:  hyoglossus & styloglossus. Laterally:  mylohyoid muscle &  superficial part of the gland. Superiorly:  lingual nerve & submandibular ganglion.  It is covered by the mucous membrane of floor of the mouth. Inferiorly:  hypoglossal nerve.

85. It emerges from the anterior end of the deep part of the gland. It passes forward along the side of the tongue, beneath the mucous membrane of the floor of the mouth. It is crossed laterally by the lingual nerve. It then lies between the sublingual gland and the genioglossus muscle. It opens at the summit of a small papilla, situated at the side of the frenulum of the tongue. The duct and the deep part of the gland could be palpated through the mucous membrane of the floor of the mouth.

86. The sublingual gland lies beneath the mucous membrane (sublingual fold) of the floor of the mouth, close to the frenulum of the tongue It has both serous and mucous acini. The sublingual ducts (8 to 20 in number) open into the mouth on the summit of the sublingual fold. Nerve Supply Parasympathetic secretomotor supply is from the facial nerve via the chorda tympani, and the submandibular ganglion. Postganglionic fibers pass directly to the gland. Sublingual Gland

87.  Relations: › Anteriorly : the gland of the opposite side › Posteriorly: › deep part of the submandibular gland › Medially: › genioglossus muscle, › lingual nerve & › submandibular duct › Laterally: › sublingual fossa of the mandible › Superiorly: › mucous membrane of the floor of the mouth. The gland forms the sublingual fold. › inferiorly: › mylohyoid muscle.

88. Blood supply: facial and lingual arteries. Venous drainage: into the facial and lingual veins. Lymph drainage: submandibular & deep cervical lymph nodes.

89. Small parasympathetic ganglion Location: on the lateral surface of the hyoglossus muscle. Suspended from the lingual nerve by several branches; Preganglionic parasympathetic fibers reach the ganglion from the superior salivary nucleus of the facial nerve via the chorda tympani & lingual nerves. The pre-ganglionic fibers synapse within the ganglion, and the post­ganglionic fibers pass to the submandibular & sublingual salivary glands.

90. SUBMANDIBULAR GANGLION

91. NERVE SUPPLY Parasympathetic secretomotor supply from the superior salivary nucleus of the seventh cranial nerve. The nerve fibers pass –to the submandibular ganglion via –the chorda tympani nerve and –the lingual nerve. Postganglionic parasympathetic fibers pass to the gland via the lingual nerve.

92. NERVE SUPPLY Postganglionic sympathetic fibers reach the gland as a plexus of nerves around the facial and lingual arteries.

93. The submandibular lymph nodes are situated on the superficial surface of the submandibular salivary gland. They can be palpated just below the lower border of the body of the mandible. They receive lymph from a wide area, including the anterior two thirds of the tongue (except the tip); the floor of the mouth & vestibule; and the gums. The efferent lymph vessels drain into the deep cervical lymph nodes. The submental lymph nodes are situated in the submental triangles. They receive lymph from tip of the tongue, floor of the mouth beneath the tip of the tongue, incisor teeth and the associated gums, center part of the lower lip, skin over the chin. The efferent lymph vessels drain into the submandibular and deep cervical lymph nodes.

94. The deep cervical lymph nodes form a chain along the course of the internal jugular vein, from the skull to the root of the neck. They are embedded in the fascia of the carotid sheath and the tunica adventitia of the internal jugular vein; Most lie on the anterolateral aspect of the internal jugular vein. Two of the nodes are often referred to clinically and are called the jugulodigastric node and the jugulo- omohyoid node.

95. The jugulodigastric node lies just below the posterior belly of the digastric muscle and is located just below and behind the angle of the mandible. It is chiefly concerned with the lymph drainage of the tonsil and the tongue. The jugulo-omohyoid node is related to the intermediate tendon of the omohyoid muscle and is associated mainly with the lymph drainage of the tongue.