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Oral region
Oral region
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Oral region includes oral cavity, teeth, gingivae, tongue, palate and palatine
tonsils
Food is ingested, chewed by teeth, and saliva from the salivary glands
facilitates formation of a bolus
Deglutination is voluntarily initiated in the oral cavity
o Involuntary phase then kicks in once bolus reaches the pharynx

Oral cavity
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Oral cavity (mouth) has two parts – oral vestibule and oral cavity proper
Taste, mastication and lingual manipulation of food
Oral vestibule is slit-like space between teeth and gingivae and the lips and
cheeks; communicates with exterior vial oral fissure
o Size of fissure controlled by peri-oral muscles (orbicularis oris,
buccinators, risorius, depressors and elevators of lips)
Oral cavity proper is space between upper and lower dental arches/arcades
o Limited laterally and anteriorly by dental arches
o Roof is formed by the palate
o Posteriorly communicates with the oropharynx
o Fully occupied by tongue when mouth is closed

Lips, cheeks and gingivae
Lips and cheeks
Lips
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Lips are mobile, musculofibrous folds surrounding the mouth
Extend from nasolabial sulci and nares laterally and superiorly to the
mentolabial sulcus inferiorly
Contain orbicularis oris and superior and inferior labial muscles, plus vessels
and nerves
Covered internally with mucous membrane and externally by skin
Function as the valves of the oral fissure
The sphincter (orbicularis oris) controls entry
Function for grasping food, sucking liquids, forming speech, osculation
Transitional zone of the lips continues into the oral cavity where it is continuous
with the mucous membrane (labia mucosa), covering the intra-oral vestibular
part of the lips
Labia frenula are free edged folds of mucous membrane in the midline,
extend from vestibular gingiva to mucosa of both upper and lower lips
Superior and inferior labial arteries (branches of facial, infra-orbital (branch of
CN V2) and mental arteries (branch of CN V3)) anastomose in the lips

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Lymph passes from the upper and lateral parts to the submandibular lymph
nodes, lymph from medial lower lip passes to submental lymph nodes

Taken from Moore et al, Clinically Oriented Anatomy, Seventh Edition

Taken from Moore et al, Clinically Oriented Anatomy, Seventh Edition

Cheeks
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Same structure as lips and continuous with them
Moveable part of the oral cavity
External aspect is the buccal region, borders are
o Anterior: oral and mental regions
o Superior: zygomatic region
o Posterior: parotid region
o Inferior: inferior part of mandible
Main muscles are buccinators
Numerous small buccal glands lie between the mucous membrane and the
buccinators
Buccal fat pads superficial to the buccinators
Supplied by buccal branches of the maxillary artery and innervated by
buccal branches of the mandibular nerve (CN V3)

Gingivae
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Gums, composed of fibrous tissue covered with mucous membrane
Gingivae proper are firmly attached to alveolar processes of the mandible
and maxilla and necks of the teeth
Pink, stippled and keratinising
Alveolar mucosa is the unattached gingiva, and is normally shiny red and
non-keratinizing

Taken from Moore et al, Clinically Oriented Anatomy, Seventh Edition

Teeth
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Main functions
o Incise, reduce and mix food with saliva during mastication
o Articulation
Set in tooth sockets
Deciduous (primary) or permanent (secondary)
Children have 20 deciduous teeth, adults have 32 permanent ones
Type of teeth and characteristics
o Incisors: thin cutting edges (2 per side, total 8)
o Canines: singular prominent cones (1 each side, total 4)
o Premolars (bicuspids): two cusps (2 on each side, total 8)
o Molars: three or more cusps (3 on each side, total 12)
Parts and structure
o Crown, root and neck
o Mostly dentine covered by enamel over the crown and cement over
the root
o Pulp cavity contains connective tissue, vessels and nerves
o Apical/root foramen where vessels and nerves exit
Tooth sockets are the alveolar processes of the maxillae and mandible
Supplied by the superior and inferior alveolar arteries (branches of the
maxillary artery)
Alveolar veins have same distribution and names, and accompany the
arteries
Lymphatic vessels of teeth and gingivae drain to submandibular lymph nodes
Innervation from superior (CN V2) and inferior (CN V3) alveolar nerves

Taken from Moore et al, Clinically Oriented Anatomy, Seventh Edition

Taken from Moore et al, Clinically Oriented Anatomy, Seventh Edition

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Palate
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Forms the arched roof of the mouth and floor of the nasal cavities
Separates oral cavity from the nasal cavities and nasopharynx
Superior surface covered in respiratory mucosa, and inferior surface
with oral mucosa
2 regions – hard and soft palate

Hard palate
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Vaulted are mostly filled by the tongue
Anterior 2/3 has a bony skeleton formed by palatine processes of the
maxillae and palatine bones
Incisive fossa is the depression in the midline, posterior to central
incisors, where incisive canals open
Nasopalatine nerves pass from nose through incisive canals
Greater palatine foramen pierces the boy palate medial to 3rd molar
tooth, where greater palatine vessels and nerves emerge
Lesser palatine foramina are posterior, transmitting lesser palatine
nerves

Soft palate
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Moveable posterior 1/3 of the palate
Palatine aponeurosis attaches to posterior edge of hard palate; blends
with muscular part
Posteroinferiorly is the curved free margin, where the uvula hangs
During swallowing, the bolus is squeezed against the soft palate by the
tongue; the soft palate is then elevated posteriorly and superiorly
against the wall of the pharynx, preventing passage of food into the
nasal cavity
Laterally it is continuous with the wall of the pharynx, and is joined to
the tongue and pharynx by the palatoglossal and pharyngeal arches
Fauces is the space between the oral cavity and the pharynx,
bounded
o Superiorly: soft palate
o Inferiorly: root of the tongue
o Laterally: pillars of the fauces (palatoglossal and
palatopharyngeal arches
Isthmus of the fauces is the short space connecting the oral cavity
proper with the oropharynx, bounded anteriorly by the palatoglossal
folds and posteriorly by the palatopharyngeal folds

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Palatine tonsils located either side of the oropharynx, located in a
tonsillar sinus (fossa)

Taken from Moore et al, Clinically Oriented Anatomy, Seventh Edition

Taken from classes
...
edu, The Digestive System, available at
http://classes
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edu/carterp/Courses/bio211/chap23/chap23
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com, Soft Palate and Pharynx, available at
http://pocketdentistry
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blogspot
...
blogspot
...
html

Inferior surface of the tongue
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Covered with thin, transparent mucous membrane
Connected to the floor of the mouth by the frenulum, which allows the
anterior tongue to move freely
Sublingual caruncle (papilla) lies each side at the base, where the
opening of the submandibular duct of the submandibular salivary
gland opens

Taken from Your Article Lbrary, Mouth, Useful Notes on Mouth Anatomy,
avaiable at http://www
...
com/biology/humanbeings/mouthuseful-notes-on-mouth-human-anatomy/9702/
Muscles of the tongue
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Muscles do not act in isolation, and some perform multiple actions
Some can act independently to produce different actions
Extrinsic muscles generally alter the position of the tongue and intrinsic
muscles alter shape
The intrinsic and extrinsic muscles are separated by a median fibrous
septum, which merges posteriorly with the lingual aponeurosis

Four extrinsic muscles
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Genioglossus, hyoglossus, styloglossus, palatoglossus
Originate outside the tongue and attach to it
Move the tongue and can alter its shape

Four intrinsic muscles
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Superior and inferior longitudinal, transverse and vertical muscles
Attachments are entirely within the tongue, not attached to bone

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Superior and inferior longitudinal muscles make the tongue short and
thick and retract protruded tongue
Transverse and vertical muscles make the tongue long and narrow,
and protrude it forward

Taken from Clinicalgate, Oral Cavity, available at http://clinicalgate
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blogspot
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uk/2015/06/86-tongue
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blogspot
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uk/

Arteries and veins of the tongue
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Derived from the lingual artery (arises from external carotid)
Dorsal lingual supply the root of the tongue, the deep lingual supply
the lingual body
Dorsal lingual veins accompany the arteries
Deep lingual veins join to the sublingual veins, which may drain to the
IJV

Lymphatic drainage of the tongue
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Mostly follows the venous drainage, but lymph from the apex, frenulum
and central lower lip run differently
Root of the tongue drains to the superior deep cervical nodes
Medial body drains to inferior deep cervical nodes
Lateral body drains to submandibular nodes
Apex and frenulum drains to submental nodes
All of them ultimately drain to the deep cervical nodes

Salivary glands
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Comprise the parotid, submandibular, and sublingual glands
Saliva is clear, tasteless, odourless, viscous fluid secreted by these
glands and mucous glands of the oral cavity
Functions
o Keep mucous membranes moist
o Lubricates food during mastication
o Begins starch digestion
o Intrinsic mouthwash
o Prevention of tooth decay and ability to taste
Small accessory glands scattered over palate, tongue, lips, cheek

Parotid glands
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Largest of the three paired salivary glands
Enclosed within a tough capsule called the parotid sheath
Parotid bed is inferior to the external acoustic meatus, between the
mandible and the mastoid process
Parotid duct passes horizontally from anterior edge, pierces the
buccinator and enters the oral cavity through a small orifice near the
second maxillary molar
Parotid plexus of the facial nerve (CN VII) is embedded within the
gland; retromandibular vein and external carotid artery also
embedded

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Parotid lymph nodes located on the sheath and within the gland
The auriculotemporal nerve (branch of CN V3) is closely related to the
gland and innervates the sheath along with the great auricular nerve
(branches of cervical plexus C2 and C3)
PNS component of glossopharyngeal nerve (CN IX) supplies fibres to
the otic ganglion; stimulation produces thin, watery saliva
SNS fibres from cervical ganglia (via carotid nerve plexus) and reduce
salivation

Submandibular glands
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Submandibular glands lie along the mandible
Submandibular duct opens in a small sublingual papilla beside the
base of the lingual frenulum
Arterial supply from the submental artery, veins accompany them
Lymph drainage to the deep cervical lymph nodes
Supplied by PNS fibres from facial nerve via chorda tympani

Sublingual glands
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Smallest and most deeply situated salivary glands
Lies in the floor of the mouth between the mandible and genioglossus
Glands from each site unite to form a horseshoe mass around
connective tissue frenulum
Sublingual ducts open into the floor of the mouth along the sublingual
folds
Arterial supply is via the sublingual (branch of lingual) and submental
arteries (branch of facial)
Nerves accompany those of the submandibular gland
PNS fibres conveyed by facial and chorda tympani and lingual nerves

Taken from ENT Allery and Sinus Center, Salivary Glands, available at
http://entallergyandsinus
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Moore et al
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Seventh Edition

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