ORAL MUCOSA
Oral Mucosa
• first space of the mouth
– laterally and in front:
alveolar arches
– posteriorly: isthmus of
the fauces
• it is a nearly ovalshaped cavity
Anatomy
• two rows of teeth supported by facial bones of the
skull, the maxilla above and the mandible below
• teeth are surrounded by gingiva, which supports
the tissue of oral cavity protection
• other structures that aid chewing are the lips,
cheeks, tongue, hard palate, soft palate, and floor
of the mouth
Anatomy
• Vestibule
– externally: lips and cheeks
– internally: gums and teeth
– communicates with the surface of the body by
the rima or orifice of the mouth
– receives the secretion from the parotid salivary
glands
Anatomy
• Mouth Cavity Proper
– cavum oris proprium
– laterally and in front: alveolar
arches with their contained teeth
– behind: communicates with the
pharynx by isthmus faucium
– roofed by the hard and soft palates,
floor is formed by the tongue
– receives the secretion from the
submaxillary and sublingual
salivary glands
Anatomy
• Lips
– labia oris
– surround the rima or
orifice of the mouth
– externally: integument
– internally: mucous
membrane
– inner surface is connected
in the middle line to the
corresponding gum by the
frenulum
Anatomy
• Gums
– gingivœ
– dense fibrous tissue
– closely connected to the periosteum of the
alveolar processes, and surrounding the necks
of the teeth
– covered by smooth and vascular mucous
membrane
Anatomy
• Hard Palate
– palatum durum
– anterior and lateral:
alveolar arches and
gums
– continuous with the
soft palate
– covered with stratified
squamous epithelium
– furnished with
numerous palatal
glands
Anatomy
• Soft Palate
– palatum molle
– movable fold,
suspended from the
posterior border of the
hard palate
– forms an incomplete
septum between the
mouth and pharynx
Anatomy
• Soft Palate
– anterior surface:
concave, continuous
with the roof of the
mouth, and marked by
a median raphé
– posterior surface: is
convex, and
continuous with the
mucous membrane
covering the floor of
the nasal cavities
Anatomy
– upper border: attached to the posterior margin of
the hard palate
– sides: blended with the pharynx
– lower border: free
– palatine velum: hangs like a curtain between the
mouth and pharynx
– palatine uvula: small, conical, pendulous process
that hangs from the middle of its lower border
– arches or pillars of the fauces: two curved folds
of mucous membrane, containing muscular fibers
Anatomy
• Teeth
– dentes
– deciduous or milk teeth
• twenty in number: four
incisors, two canines, and
four molars
– permanent teeth
• thirty-two in number: four
incisors, two canines, four
premolars, and six molars
Anatomy
• Teeth
– crown: projecting above the gum
– root: embedded in the alveolus
– neck: the constricted portion between the
crown and root
Anatomy
Lower central incisors
6 to 9 months.
Upper incisors
8 to 10 months.
Lower lateral incisors
and first molars
15 to 21 months.
Canines
16 to 20 months.
Second molars
20 to 24 months.
Anatomy
First molars
6th year.
Two central incisors
7th year.
Two lateral incisors
8th year.
First premolars
9th year.
Second premolars
10th year.
Canines
11th to 12th year.
Second molars
12th to 13th year.
Third molars
17th to 25th year.
Salivary Glands
• Parotid Gland
–
–
–
–
glandula parotis
largest of the three
weight: 14-28 gm
side of the face, below
and in front of the
external ear
– main portion of the gland:
between the ramus of the
mandible in front and the
mastoid process and
sternocleidomastoideus
behind
Salivary Glands
• Submaxillary Gland
– glandula submaxillaris
– size of a walnut
– situated in the submaxillary
triangle
– submaxillary duct: 5 cm. long
• opens by a narrow orifice on the summit of a small papilla, at
the side of the frenulum linguæ
• lies between the lingual and hypoglossal nerves, but at the
anterior border of the muscle it is crossed laterally by the
lingual nerve
• Vessels and Nerves
– blood supply: branches of the external maxillary and
lingual
– nerves: submaxillary ganglion
• receives filaments from the chorda tympani of the facial nerve
and the lingual branch of the mandibular nerve
Salivary Glands
• Sublingual Gland
– glandula sublinguali
– smallest of the three
glands
– beneath the mucous
membrane of the floor of
the mouth, at the side of
the frenulum linguæ
– weighs nearly 2 gm
– Above: mucous membrane; below: Mylohyoideus;
behind: deep part of the submaxillary gland; lateral:
mandible; and medial: Genioglossus
– separated by the lingual nerve and the submaxillary
duct
• excretory ducts: 8-20
– ducts of Rivinus join the submaxillary duct
– duct of Bartholin joins the sublingual duct which opens
into the submaxillary duct
• sublingual and submental arteries
• nerves: lingual, the chorda tympani, and the sympathetic
innervation
Anatomy
• Accessory Glands
– posterior part of the dorsum of the tongue behind the
vallate papillæ
– large numbers are present in the soft palate, the lips,
and cheeks
– same structure as the larger salivary glands
– mucous or mixed type
Function
• begins digestion by mechanically
breaking up the solid food
particles into smaller pieces and
mixing them with saliva
• plays an important role in speech,
facial, expression,kissing, eating,
drinking, breathing
– infants: sucking reflex
Diseases
Cleft Lip and Palate
• cheiloschisis and palatoschisis
• failure of fusion of the maxillary and medial nasal
processes
• cleft is a fissure or opening—a gap
– non-fusion of the body's natural structures that form
before birth
Cleft Lip
• small gap or an
indentation in the lip
(partial or incomplete
cleft) or it continues
into the nose
(complete cleft)
• lip cleft can occur as a
one sided (unilateral)
or two sided (bilateral)
Cleft Lip
• within the first 2–3 months after birth,
surgery is performed to close the cleft lip
• "rule of 10s" (Wilhelmmesen and Musgrave
in 1969)
– the child is at least 10 weeks of age
– weighs at least 10 pounds
– at least 10g hemoglobin
Cleft Palate
• condition in which the two
plates of the skull that form the
hard palate (roof of the mouth)
are not completely joined.
• failure of fusion of the lateral
palatine processes, the nasal
septum, and/or the median
palatine processes (formation
of the secondary palate)
Cleft Palate
• occur as complete (soft and hard palate, possibly including a gap
in the jaw) or incomplete (a 'hole' in the roof of the mouth,
usually as a cleft soft palate)
• a direct result of an open connection between the oral cavity and
nasal cavity is velopharyngeal insufficiency
• corrected by surgery usually performed between 6 and 12
months
• 20-25% only require one palatal surgery to achieve a competent
velopharyngeal valve capable of producing normal, nonhypernasal speech
Malignant Tumors
• Lips
– squamous cell carcinoma of the lower lip (90%)
– risk factors: pipe smokers, prolonged intense
sun exposure
– symptoms: intractable ulcerations in the
vermillion border, large exophytic lesions
– diagnostic: biopsy
– treatment: surgical excision
– low rate of metastasis to regional lymph nodes
Malignant Tumors
• Oral Cavity
– squamous cell carcinoma
– risk factors: long history of nicotine and alcohol
abuse
– symptoms: painful swallowing, blood-tinged
saliva, fetid breath odor
– diagnosis: visual inspection, bimanual
palpation, imaging
– treatment: surgery and radiation therapy