oral cavity

Oral Cavity

• The oral cavity is important for respiration, eating, and speech production
• Three major salivary glands drain into the oral cavity and aid in softening and moistening food for initial digestion

Oral Cavity Divisions

• Oral vestibule sits superficially between the lips and cheeks, as well as the teeth and buccal gingiva, deeply
• The oral vestibule communicates with the oral cavity proper through the frenulum of the tongue, and with the exterior through the oral fissure
• The oral fissure is the opening between the lips
• The oral cavity proper is posterior and medial to the dental arches or arcades (maxillary and mandibular)

Boundaries of the Oral Cavity Proper

• Roof: hard and soft palate
• Floor: tongue and mylohyoid
• Lateral: cheeks and tonsillar pillar (posteriorly)
• Posterior: communicates with the oropharynx

Structures of the Oral Cavity Proper

• Sublingual region sits inferior to the mobile portions of the tongue
• The frenulum linguae connects the tongue to the floor of the mouth
• Deep lingual veins are localized on each side of the frenulum
• The opening of the submandibular duct is localized on each side of the frenulum
• The plica sublingualis overlies the superior border of the sublingual salivary gland
• The hamulus is the medial pterygoid plate

Lips

• Mobile musculofibrous folds make up the lips
• Skin covers the external part of lips
• Mucosa covers the internal part of lips
• Lips extend from the nasolabial sulcus (superiorly) to the mentolabial sulcus (inferiorly)
• Functions of lips are to grasp food, suck liquids, keep food out of the vestibule, aid in speech and osculation
• Lips are associated with the orbicularis oris muscle, as well as superior and inferior muscles associated with the upper and lower lip

Labial Frenula (Labial Frena)

• Free-edge mucous membrane folds extend from the labial mucosa to the vestibular gingiva in both upper and lower lips
• Labial frenulum is surgically correctable by a frenulectomy
• Congenital anomaly of the lip is called cleft lip
• About 1 in 1,000 people have a cleft lip
• 60-80% of cleft lip cases are male
• A cleft lip can be either unilateral or bilateral
• Labial frenula connect the lips to the gingiva internally
• The upper maxillary labial frenum is larger than the lower mandibular buccal frenum:

Blood Supply, Motor Innervation, Sensory Innervation, and Lymph Nodes of the Upper Lip

• Blood supply: superior labial and infraorbital arteries
• Motor innervation: zygomatic and buccal branch of CN VII
• Sensory innervation: superior labial branches from CN V2
• Lymph nodes: submandibular

Blood Supply, Motor Innervation, Sensory Innervation, and Lymph Nodes of the Lower Lip

• Blood supply: inferior labial and mental arteries
• Motor innervation: buccal and mandibular marginal branch of CN VII
• Sensory innervation: inferior labial branches from mental nerves CN V3
• Lymph nodes: submandibular (lateral side) and submental (medial side)

Arteries of the Lip

• Superior and inferior labial arteries anastomose, forming an arterial ring
• The upper lip gets its blood supply from branches of the infraorbital artery
• The lower lip gets its blood supply from mental arteries

Cyanosis of the Lip

• Cyanosis is when the lip has a purplish coloration due to deficient oxygenation of the capillary blood
• Can be a sign of a pathological condition

Sensory innervation of the Lip

• Superior labial branches of infraorbital nerves (CN V2) provide sensory innervation
• Inferior labial branches of mental nerves (CN V3) provide sensory innervation

Lymph Nodes of the Lip

• The submandibular lymph nodes primarily receive lymph from the upper lip & lateral parts of the lower lip
• The submental lymph nodes receive lymph that initially comes from the medial lip

Oral Cavity

• The oral cavity has two parts; vestibule and oral cavity proper
• The vestibule is the space bounded by the lips anteriorly, cheeks laterally, gingiva, and teeth posteriorly
• The oral cavity is the space posterior to the lips, anterior to the tonsils, and the soft palate
• Oral fissure=opening
• Oropharyngeal isthmus=entrance into the oropharynx
• Buccinator muscle forms the lateral wall of the vestibule

Cheeks (L. buccae)

• The buccinator muscle forms the cheeks
• Cheeks are a movable lateral wall of the oral cavity
• Buccal fat pads are also located in the cheeks, and are larger in infants
• Blood supply to the cheeks is from the buccal artery via branches
• The motor innervation of the cheeks comes from the buccal branch of CN VII (Facial)
• The sensory innervation of the cheeks come from the buccal nerve (branch of CN V3)
• Functions of cheeks include compressing the cheeks, expelling air between lips, and aiding in mastication

External Boundaries of the Cheeks

• Anterior boundary: lips and chin
• Posterior boundary: parotid region
• Superior boundary: zygomatic region
• Inferior boundary: mandible (inferior border)
• Zygomatic bone and arch create a prominence of cheek

Gingivae

• Mucous membrane covers the fibrous tissue of the gingivae
• Gingiva proper (attached gingiva) is attached to the alveolar processes of the jaws and the neck of the teeth; it is pink and keratinized
• Alveolar mucosa (unattached gingiva) is shiny red and non-keratinized
• Gingivitis is when the gingiva is inflamed from bad oral hygiene and it may spread to other supporting structures, including alveolar bone-producing periodontitis

Teeth

• A child has 20 deciduous teeth
• An adult has 32 permanent teeth
• Incising, reducing, and mixing food with saliva during mastication are that part of the chief functions
• Also assists with articulation of speech
• Each tooth has a crown, neck, and root

Tooth Identification

• Tooth type is either deciduous/primary versus permanent/secondary
• Identified by what type of tooth, and Proximity to the midline or front of the mouth (mesial vs distal)

Timing of Tooth Eruption

• The first teeth (medial incisors) may not erupt until 12-13 months
• Central Incisor (CI) erupts at 6-8 months and shedding occurs at 6-7 years in deciduous teeth
• Lateral incisor (LI) erupts at 8-10 months and shedding occurs at 7-8 years in deciduous teeth
• Canine (C) erupts at 16-20 months and shedding occurs at 10-12 years in deciduous teeth
• 1st Molar erupts at 12-16 months and shedding occurs at 9-11 years in deciduous teeth
• 2nd Molar erupts at 20-24 months and shedding occurs at 10-12 years in deciduous teeth
• Lower Central Incisor (CI) erupts at 7-8 years in permanent teeth
• Lower Lateral incisor (LI) erupts at 8-9 years in permanent teeth
• Canine (C) erupts at 10-12 years in permanent teeth
• 1st Premolar erupts at 10-11 years in permanent teeth
• 2nd Premolar erupts at 11-12 years in permanent teeth
• 1st Molar erupts at 6-7 years in permanent teeth
• 2nd Molar erupts at 12 years in permanent teeth
• 3rd Molar erupts at 13-25 years in permanent teeth

Tooth Composition

• Each tooth is composed of dentine that is covered by enamel over the crown
• Cement covers the root
• Pulp cavity contains connective tissue, blood vessels and nerves
• The periodontal membrane connects the cement of the root with the periosteum
• Root canal (pulp canal) transmits the nerve and vessels from the pulp cavity through the apical foramen

Syndesmosis & Periodontal Membrane

• Gomphosis or dento-alveolar syndesmosis –fibrous joint
• Periodontal membrane is composed of collagen fibers between the cement and periosteum
• Tactile, pressoreceptive nerve endings, lymph capillaries and glomerular blood vessels supply the periodontal membrane
• Tooth sockets are found in the alveolar processes, separated from interradicular septa

Vasculature of Teeth

• Maxillary teeth: Superior (Anterior, Middle and Posterior) Alveolar arteries supply them
• Mandibular teeth: Inferior Alveolar artery supplies them
• Veins share the same names and distribution

Sensory Innervation of Teeth

• Superior (Anterior, Middle and Posterior) Alveolar nerves (from CNV2) provide sensory innervation to maxillary teeth
• Inferior alveolar nerve (from V3) provides sensory innervation to mandibular teeth
• Take caution to avoid injury to the lingual nerve when extracting the third molar where it passes to its medial aspect

Lymphatic Drainage of Teeth/Gingivae

• Lymphatic vessels from the teeth and gingivae mainly pass to the submandibular lymph nodes

Sensory Innervation and Blood Supply for Maxillary Teeth

• Incisives and canine get their blood supply from Anterior superior alveolar aa, and their sensory innervation from Dental plexus from Superior alveolar (CN V2) nerves and Anterior superior alveolar nn
• Premolars get their blood supply from Middle superior alveolar aa, and their sensory innervation from Middle superior alveolar nn, with the lymph nodes being submandibular
• Molars get their blood supply from Posterior superior alveolar aa, and their sensory innervation from Posterior superior alveolar nn, with the lymph nodes being submandibular
• Sensory Innervation and Blood Supply for Mandibular Teeth
• Mandibular teeth get their blood supply from the Inferior alveolar aa, and their sensory innervation comes from the Dental plexus from inferior alveolar (CN V3) nerves

Tongue

• A mobile muscular organ
• Localized partly in the oral cavity and partly in the oropharynx
• When the mouth is closed, the tongue occupies the oral cavity
• Attached by muscles to the hyoid bone, mandible, styloid process, palate and pharynx
• Involved in mastication, taste, swallowing, articulation, oral cleansing, squeezing food into the oropharynx, forming words during speaking

Tongue surface

• Dorsum of the tongue = top
• Features include: Epiglottis, median epiglottic fold, vallecula of epiglottis, foramen cecum (non-functional remnant of thyroglossal duct), sulcus terminalis, apex, inferior surface
• The root of the tongue makes up 1/3
• The body of the tongue makes up 2/3 and is extremly mobile

Parts and Surface of the Tongue

Body

• The anterior 2/3 of the tongue divided into left and right parts by a midline grove
• The mucous membrane is relatively thin and covered with squamous epithelium
• The rough texture is due to the presence of small taste buds (lingual papillae)

Root

• The posterior third of the tongue which is fixed and attached to the hyoid bone and mandible

Apex (tip)

• The pointed anterior part of the body, resting in the incisors

Dorsum

• The posterosuperior surface including the terminal sulcus
• The sulcus divides the dorsum into the anterior and posterior parts, located in the oral cavity proper and the oropharynx, respectively.

Inferior Surface

• Faces the floor of the mouth, covered by a thin, transparent mucous membrane
• The frenulum connects the tongue to the floor of the mouth in the midsagittal plane
• Laterally is the sublingual caruncle with the opening of the two submandibular glands
• More laterally are the openings of the sublingual glands

Other Features of the Tongue

• Dorsum versus Inferior surface of the tongue
• Lingual papilla provides the tongue a rough appearance

Lingual Papillae

• Located in the anterior 2/3 of the tongue
• The lingual tonsil is the collective term for the lingual lymphatic follicles
• 4 types:Vallate, Filiform, Foliate, and Fungiform
• Vallate large and flat topped, arranged in a V-shaped, anterior to the terminal sulcus, contain taste receptors, and they're innervated by CN IX.
• Foliate have small lateral folds of the lingual mucosa and are poorly developed in human
• Filiform are long and numerous, contain afferent nerve endings, arranged in V-shaped (parallel to the terminal sulcus), contain taste receptors
• Fungiform are mushroom-shaped pink or red spots scattered among the filiform papillae, are most numerous at the apex and margins of the tongue, and contain taste receptors

Tongue and Frenulum

• The frenulum of the tongue connects the inferior surface to the floor of the mouth
• A frenectomy cuts the frenulum to free the tongue for normal speech
• Sublingual caruncle aids opening of salivary glands

Muscles

• The tongue is a mass of muscles all covered by mucous membrane
• These muscles do not act in isolation and perform multiple joint actions
• Extrinsic muscles of the tongue alter the position, but can alter shape as well
• Intrinsic muscles of the tongue alter its shape
• There are a total of eight muscles per side, separated by the lingual septum and covered by mucous membrane

Extrinsic Muscles

• Three of the extrinsic muscles are innervated by the CN XII (Hypoglossal n.): genioglossus, hyoglossus, & styloglossus
• The forth palatoglossus muscle is by CN X (Vagus) provides the innervation
• Styloglossus retracts and elevates
• Genioglossus depresses and protrudes the tongue If paralyzed, the tongue mass tends to shift posteriorly
• Hyoglossus depresses and retracts
• Palatoglossus elevates the posterior part of the tongue

Intrinsic muscles of the Tongue

• Alter its shape
• Attachments are entirely within the tongue
• Paralysis of CN XII causes a tongue deviation to the paralyzed side when the tongue is protruded
• They are arranged in longitudinal, transverse and vertical bundles, forming much of the bulk of the tongue

Attachments, Blood Supply, Innervation, and Action of the Extrinsic Muscles of the Tongue

Genioglossus

• Mental spine (mandible) to dorsum of the tongue and body of hyoid bone
• Sublingual and submental arteries supply it
• CN XII innervates it
• It depresses and protrudes the tongue, forming the bulk of the tongue

Hyoglossus

• Hyoid bone (body and greater horn) to lateral and inferior aspect of the tongue
• Sublingual artery supplies it
• CN XII innervates it
• It depresses and retracts the tongue

Styloglossus

• Styloid process and stylohyoid ligament to the lateral and inferior aspect of the tongue
• Sublingual artery supplies it
• CN XII innervates it
• It retracts and elevates the tongue

Palatoglossus

• Palatine aponeuroses of the soft palate and attaches to the side of the tongue
• Ascending pharyngeal and the palatine branch of facial and maxillary arteries supply it
• CN X innervates it
• It elevates the posterior part of the tongue, forming the Palatal group muscle

Sensory Innervation of the Tongue

• Internal laryngeal branch of vagus n. (CN X) provides general sensation and taste
• Lingual branch of glossopharyngeal n. (CN IX) provides general sensation and taste (posterior 1/3 of tongue and vallate papillae)
• Lingual n. (CN V3) provides general sensation (touch and temperature) and for special sensation (taste) by chorda tympani CN VII (anterior 2/3 of tongue), except for the vallate papillae
• CN IX – afferent limb of the gag reflex

Basic Taste Sensations

• BITTER (posterior)

• SOUR (posterior)

• SALTY (lateral)

• SWEET (apex)

• Receptors for salt & sweet are clustered anterior to those for bitter & sour; (smell and aroma are olfactory)

• Taste fibers of lingual nerve are derived from the geniculate ganglion and join the lingual nerve by way of the chorda tympani, while Taste fibers of the CN IX enter the brain stem with it and have their cells of origin in the inferior (petrosal) ganglion of the ninth

• Taste(CN V3)

CN XII and Tongue

• Provides Somatic Motor innervations
• Supplies All Tongue, the exceptions are
  • Intrinsic
  • Extrinsic Muscles
  • palatoglossus by CN X
• After passing through the hypoglossal canal,CN XII turns sharply inferior and runs several cm in the carotid sheath, then enters the digastric triangle in the neck above the level of hyoid bone to ramify and reach the tongue muscles.
• Lesion to the distal portion results in paralysis, which deviates the the affected side because of contraction of the genioglossus

Lingaual Arteries

• The lingual artery, along with its branches, is the primary artery supplying the tongue
• Dorsal Lingual supplies Root of The Tongue, and sends a branch to the Palatine tonsil
• Deep lingual provides the Body of the Tongue and communicates with each other
• Sublingual supplies the Sublingual Gland and the floor of the mouth
• Origination Level to the level of the greater horn of hyoid bone in the carotid triangle and passed the hyoglossus muscle.

Lingual Vein

• The CN XII, submandibular duct & lingual nerve all lie on the lateral surface of the hyoglossus m., while the lingual artery is deep in this muscle
• The superior pharyngeal constrictor muscle
• The Dorsal runs with arterial counterparts
• Deep is the apex end of joining sublingual
• It's direct or indirect in the IJV with sublingual counterparts.

Blood Supply, Innervation, and Action of Muscles Related to the Floor of the Oral Cavity

Geniohyoid

• Attachments: Inferior tubercle on back of symphysis of mandible to body of hyoid bone
• Blood Supply: Sublingual branch of lingual artery
• Innervation: C1
• Action: Elevates hyoid bone, Depresses Mandible; Suprahyoid muscle

Mylohyoid

• Attachments: Mandible, median raphe & hyoid bone
• Blood supply: Sublingual branch of lingual artery and Submental branch from facial artery
• Innervation: Nerve to mylohyoid

Sublingual absorption

• It bypasses fast to allow through through bacoocal the membrane

Lymphatic Drainage of Tongue

• Lingual carcinoma: Posterior third= superior deep cervical cord The Medial: Inferior Cord. Lateral: Under the sub- region Apex: Submental/Lymph nodes.

Muscles in Floor of Mouth

• That help the floor of the mouth contribute two. They share C1- mm

Composition Layers

It is continuos constrictor in that that helps the buccophayngeal region of the and it involves the membranes of and the buccintor.

It is with in a motor membrane.

Lingual Carcinoma

• Lingual Carcinoma has 12 signs. These include but aren't limited to Sore and Ulcers after 3 weeks, lump tissue or Overgrowth, mass over 3 weeks, or unexplained mobile masses or discharge.

Glands

• Consist of 3 main including sub, lingy, lingual.

Has many accessory structures scattered amongst palates, cheeks tonsils and tongues

Submandibular Gland

• They are with the body of hypoid Supplies: Arteries It can be conveyed by facian and the the synapse is similar to others
• It is deep to the mylohyoid muscle, medial to the mandible, and inferior to the mylohyoid line
• The submandibular duct (Wharton's duct) lies between the mylohyoid and hyoglossus muscle
• The 5-cm long duct drains into the floor of the mouth through a small nodule of tissue located at the base of the frenulum of the tongue, on its inferior surface called the sublingual papilla
• The arterial supply comes from the submental branch of the facial artery
• It is innervated by parasympathetic secretomotor fibers from the facial nerve, which run in the chorda tympani (from CN VII), and in the lingual nerve to synapse in the submandibular ganglion

Sublingual Glands

• smallest and situated deepily Located with all supply to branches and facial
• The smallest and most deeply situated gland
• Located between the mandible and the genioglossus muscle, it drains into the floor of the mouth along the sublingual folds through small sublingual ducts
• It is supplied by postganglionic parasympathetic secretomotor fibers from the submandibular ganglion

Innervation Lymph

• All supplies through the main sections of the body through the face to be supplied

Palates

• The soft and hard

Hard Palates for Soft Tissue

• Consist of a skeleton and the most movable.

Hard Palate

• Palatine processes of the maxillae and horizontal processes of the palatine bones make this up
• When resting the tongue takes up much of this space.
• The greater palatine artery supplies the hard palate
• Mucosa of the hard palate gets CNV2 innervation from the greater palatine and nasopalatine nerves
• Has 3 Foramina
  • Incisive Foramina, slight dip with the incisors central
  • greater palatine

Fauch

• Are spaced in side mouth region

Mnemonic

• They are all done through P T P and the innervstatoon is in the pharyx The EXCEPT is tensor, in CNV

Tongue Taste

• Taste is the sensation of being linked the soft and long and temperature, CNIX .

Pain and taste

It is done with facial, then in the membrane where it supplies those 6 primary anterior membranes. This insertion goes through incisicve to allow sensation. Blocking causes pain!