Download ORAL REGION ORAL CAVITY Mouth consists of ORAL VESTIBULE

ORAL REGION
ORAL CAVITY
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Mouth consists of ORAL VESTIBULE and ORAL CAVITY PROPER
o Oral vestibule is the space between teeth/gingivae and lips/cheeks
 Communicates with exterior through oral fissure (opening)
 Size of fissure is controlled by circumoral muscles such as orbicularis oris
(sphincter of oral fissure), buccinator, risorius, depressors, elevators of the lips
(dilators of fissure)
o Oral cavity proper is space between upper and lower dental arches or arcades (maxillary
and mandibular alveolar arches/teeth)
 Limited laterally and anteriorly by the dental arches
 Roof of oral cavity is formed by palate
 Posteriorly, oral cavity communicates with oropharynx (oral part of the pharynx)
 Occupied by tongue when mouth is closed and at rest
LIPS, CHEEKS, AND GINGIVAE
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Lips extend from nasolabial sulci and nares laterally and superiorly to the mentolabial sulcus
inferiorly
o Contain orbicularis oris and superior and inferior labial muscles, vessels, and nerves
o Labial frenula – free edged folds of mucous membrane in the midline, extending from
the vestibular gingiva to the mucosa of the upper and lower lips
 Upper lip one is larger
o Superior and inferior labial arteries, branches of facial arteries, anastomose with each
other in the lips to form an arterial ring
 Upper lip is supplied by superior labial branches of facial and infra-orbital
arteries
 Lower lip is supplied by inferior labial branches of facial and mental arteries
o NERVES
 Upper lip is supplied by superior labial branches of infra-orbital nerves (CN V2)
 Lower lip is supplied by inferior labial branches of the mental nerves (CN V3)
o LYMPH
 From upper lip and lateral parts of lower lip pass primarily to submandibular
lymph nodes whereas lymph from the medial part of the lower lip passes
initially to submental lymph nodes
CHEEKS
o Principle muscles of cheeks are buccinators
o Buccal glands lie between the mucous membrane and the buccinators
o Superficial to buccinators are buccal fat pads
o Cheeks are supplied by buccal branches of maxillary artery and innervated by buccal
branches of mandibular nerve
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GINGIVAE
o Gingiva proper is firmly attached to alveolar processes of the mandible and maxilla and
the necks of the teeth
 Superior and inferior lingual gingivae—adjacent to tongue
 Maxillary, mandibular/buccal gingival adjacent to lips/cheeks
 Alveolar mucosa (unattached gingiva) is normally shiny red and non-keratinizing
while gingiva proper is pink stippled and keratinizing
TEETH
o Help assist the development and protection of the tissues that support them
o Participate in articulation of speech
o Deciduous – primary teeth
 Kids have 20
o Permanent – secondary teeth
 Adults have 32
o Before eruption, teeth are in alveolar arches as tooth buds
o TYPES
 Incisors
 Canines
 Premolars (bicuspids)
 Molars (3 or more cusps)
o Vestibular surface of each tooth is directed outwardly, and the lingual surface is directed
inwardly
o PARTS AND STRUCTURE OF TEETH
 Has crown, neck, and root
 Crown projects from gingiva
 Neck is between crown and root
 Root is fixed in tooth socket by periodontium
 Number of roots varies
 Most of tooth is composed of dentine, covered by enamel over crown and
cement over the root
 Pulp cavity contains connective tissue
 Root canal transmits nerves and vessels to and from the pulp cavity
through the apical foramen
 Tooth sockets are in the alveolar processes of the maxillae and mandible…
 Roots are connected to the bone of the alveolus by a springy suspension
forming a special type of joint called dento-alveolar syndesmosis or gomphosis
o VASCULATURE OF TEETH
 Superior and inferior alveolar arteries, branches of the maxillary artery, supply
the maxillary and mandibular teeth respectively
 Alveolar veins with the same names and distribution accompany the arteries
 Lymphatic vessels from the teeth and gingivae pass mainly to the
submandibular lymph nodes
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INNERVATION OF TEETH
 Superior (CN V2) and inferior (CN V3) alveolar nerves give rise to dental plexuses
that supply the maxillary and mandibular teeth
PALATE
o Forms roof of mouth and floor of nasal cavities
o Separates oral cavity from nasal cavities and nasopharynx
o Superior surface of palate is covered by respiratory mucosa
o Inferior surface covered by oral mucosa
o Consists of hard palate anteriorly and soft palate posteriorly
o HARD PALATE
 Incisive fossa is a depression in the midline of the palate
 Nasopalatine nerves pass from nose to a variable number of incisive
canals and foramina that open into the incisive fossa
 Medial to 3rd molar tooth, greater palatine foramen
 Greater palatine vessels and nerve emerge from this foramen and run
anteriorly on the palate
 Lesser palatine foramina are posterior to the greater palatine foramen transmit
the lesser palatine nerves and vessels to the soft palate and adjacent structures
o SOFT PALATE
 Palatine aponeurosis strengthens it
 Uvula is here
 When you swallow, soft palate tenses to allow the tongue to scrape the bolus of
food to the back of the mouth
 Soft palate is then elevated posteriorly and superiorly against the wall of the
pharynx, thereby preventing passage of food into nasal cavity
 Laterally, soft palate is continuous with wall of pharynx and is joined to tongue
and pharynx by palatoglossal and palatopharyngeal arches
 Fauces is space between the cavity of the mouth and pharynx
 Bounded superiorly by soft palate, inferiorly by root of tongue, and
laterally by the pillars of the fauces—palatoglossal and
palatopharyngeal arches
 ISTHMUS OF THE FAUCES
 Short constricted space that connects oral cavity proper and oropharynx
 Bounded anteriorly by palatoglossal folds and posteriorly by
palatopharyngeal folds
 Palatine tonsils are in tonsillar fossa (sinus), bounded by arches and
tongue
o SUPERFICIAL FEATURES OF PALATE
 Mucosa of hard palate is tightly bound to underlying bone—submucous
injections here are painful
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Superior lingual gingiva is gingiva covering lingual surface of teeth and alveolar
process
 Injection of anesthetic agent into gingiva of tooth anesthetizes the adjacent
palatal mucosa
 Palatine glands are deep to mucosa
 Incisive papilla are just posterior to maxillary incisors
 Transverse palatine folds
 Assist with manipulation of food during mastication
 Palatine raphe
 White streak on the roof of the mouth—marks site of fusion of the
embryonic palatal processes (palatal shelves)
MUSCLES OF SOFT PALATE
 Soft palate can be elevated so that it is in contact with posterior wall of the
pharynx—closes isthmus of the pharynx, so that you have to breathe through
your mouth
 Soft palate can also be drawn inferiorly so that it is in contact with posterior
part of tongue
 Closes isthmus of the fauces, so that expired air passes through nose
(even when mouth is open)
 Prevents substances in oral cavity from passing into pharynx
 Tensing soft palate pulls it tight at an intermediate level so that tongue may
push against it, compressing masticated food and propelling it into pharynx for
swallowing
 5 muscles of soft palate arise from cranial base and descend to palate
 Direction of pull of tensor veli palatini is redirected 90 degrees because
its tendon uses pterygoid hamulus as a pulley or trochlea, allowing it to
pull horizontally on the aponeurosis
VASCULATURE AND INNERVATION OF PALATE
 FROM GREATER PALATINE ARTERY, branch of descending palatine artery
 Greater palatine artery passes through greater palatine foramen and
runs anteromedially
 Lesser palatine artery, smaller branch of descending palatine artery,
enters palate through the lesser palatine foramen and anastomoses
with ascending palatine artery, a branch of the facial artery
 veins of the palate are tributaries of the pterygoid venous plexus
 sensory nerves of palate are branches of maxillary nerve (V2) which branch from
pterygopalatine ganglion
 greater palatine nerve supplies gingivae, mucous membrane, and glands
of most of the hard palate
 nasopalatine nerve supplies the mucous membrane of the anterior part
of the hard palate
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lesser palatine nerves supply the soft palate
nerves accompany arteries through the greater and lesser palatine
foramina respectively
except for tensor veli palatini supplied by V3, all muscles of soft palate are
supplied through pharyngeal plexus of nerves (vagus nerve)
TONGUE
o Parts and surfaces
 Root of the tongue is attached posterior portion extending between mandible,
hyoid, and vertical posterior surface of tongue
 Body of tongue is anterior, approximately 2/3rds of tongue between root and
apex
 Apex of tongue is anterior end of body, which rests against incisors
o Two surfaces
 Dorsum of tongue
 Characterized by V shaped groove, terminal sulcus
o Angle of this points to foramen cecum—nonfunctional remnant
of the proximal part of the embryonic thyroglossal duct from
which the thyroid gland developed
 Midline groove
 Also lingual papillae
 Inferior surface
 Connected to base of mouth by frenulum
 Sublingual caruncle is on either side of the frenulum—opening to
submandibular gland
o MUSCLES OF TONGUE
 Extrinsic muscles alter position of tongue
 Intrinsic muscles alter shape of tongue
 EXTRINSIC MUSCLES
 Genioglossus, hyoglossus, styloglossus, palatoglossus
 Originate outside the tongue and attach to it
 INTRINSIC MUSCLES
 Superior and inferior longitudinal muscles—make tongue short and
thick and retract the protracted tongue
 Transverse and vertical muscles make tongue long and narrow
o INNERVATION OF TONGUE
 All muscles except palatoglossus are innervated by CN XII
 General sensation – supplied by lingual nerve, branch of V3
 Taste is supplied by chorda tympani, branch of VII
 Mucous membrane of posterior 3rd of tongue is supplied by IX
 Internal laryngeal nerve, branch of vagus (X), supply mostly general but some
special sensation to a small area of tongue just anterior to epiglottis
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Mostly sensory nerves also carry parasympathetic secretomotor fibers to serous
glands in the tongue
VASCULATURE OF TONGUE
 Derived from lingual artery, off the ECA
 Dorsal lingual arteries supply root of tongue
 Deep lingual arteries supply the body
 Lingual septum keeps dorsal from communicating
 Dorsal and deep lingual veins drain into the sublingual vein
LYMPHATIC DRAINAGE OF TONGUE
 Lymph from root drains bilaterally into the superior deep cervical lymph nodes
 Lymph from medial part of body drains bilaterally to inferior deep cervical
lymph nodes
 Lymph from right and left lateral parts of body drains to submandibular lymph
nodes on ipsilateral side
 Apex and frenulum drain to submental lymph nodes
SALIVARY GLANDS
 Parotid, submandibular, sublingual glands
 Accessory salivary glands are scattered over the palate, lips, cheeks, tonsils,
tongue
 SUBMANDIBULAR GLANDS
 Lie along the body of the mandible
 Submandibular duct
 Arterial supply of the submandibular glands is from submental arteries
 SUBLINGUAL GLANDS
 Smallest and most deeply situated
 Has sublingual ducts
 Arterial supply is from sublingual and submental arteries branches of
lingual and facial arteries respectively
 Nerves of glands accompany those of submandibular gland