CHAPTER 14
Oral Cavity
261
Name of
Mucosa
Epithelium
Lamina Propria
Submucosa
Covering
Region
Special
Features
Clinical Application
Lining
mucosa
Nonkeratinized
stratif ed
squamous
epithelium
Few collagen
f bers; many
elastic f bers
Well-developed
submucosa;
attached
primarily to
underlying muscle
rather than
bone (except ±or
alveolar mucosa)
Lips, cheeks,
so±t palate,
in±erior sur±ace
o± the tongue,
and fl oor o± the
mouth
Thick, so±t,
and loose;
fl exible
and can be
stretched
Injections are easy to
make and minimally
pain±ul; i± cut, a gap
appears that requires
suturing; in±ection
spreads quickly
Masticatory
mucosa
Keratinized
stratif ed
squamous
epithelium
Dense network
o± collagen f bers;
±ew elastic f bers
No submucosa
present; lamina
propria is directly
and f rmly bound
to the bone
Gingiva, hard
palate
Thin, sti±±,
dense;
cannot be
stretched
Injections are di±f cult
and pain±ul; i± cut,
no gap results and
suturing is not
necessary; in±ection
spreads slowly
TABLE 14-1
Comparison of Lining and Masticatory Mucosae
CLINICAL CORRELATION
Figure 14-3B.
Oral Submucous Fibrosis of the Lip.
H&E,
3
25
Oral submucous ±
brosis
is a precancerous condition char-
acterized by a mucosal rigidity due to f
broelastic changes
o± the
lamina propria
and
submucosa layers
o± the
lining
mucosa
. This causes a progressive di±f
culty in opening
the mouth. It a±±ects the
buccal mucosa
,
lips
,
retromolar
areas
, the
soft palate
, and even the
esophagus
. Causes o±
this condition include the use o±
chillies
and
areca nut
,
collagen disorders
, and
autoimmune disorders
. Histologi-
cally, it is characterized by
atrophic
(thinned)
epithelium
and
increased collagen ±
ber formation
±ollowed by the
presence o± dense collagen f
ber bundles and di±±erent
degrees o±
hyalinization
. Prevention and treatments o± the
disease include dietary changes and having plastic surgery
to improve the ±unction o± the mouth.
Atrophic
epithelium
Increased
collagen fibers
B
Elastic fibers
Elastic fibers
Elastic fibers
Lamina
Lamina
propria
propria
Lamina
propria
Stratum
Stratum
basale
basale
Stratum
basale
Stratum
Stratum
spinosum
spinosum
Stratum
spinosum
Stratum
Stratum
granulosum
granulosum
Stratum
granulosum
Nonkeratinized stratified
squamous epithelium
A
Figure 14-3A.
Buccal mucosa
(l
ining mucosa)
,
cheek
.
H&E,
3
16
Each
cheek
constitutes a lateral wall o± the mouth. The inner
sur±ace o± the cheeks is lined by lining mucosa known as
buccal
mucosa
. The buccal mucosa has a nonkeratinized stratif ed
squamous epithelium with three def nite layers (stratum basale,
spinosum, and granulosum) with many elastic f bers in the
lamina propria and minor salivary glands (
buccal glands
) in the
submucosa layer. This example shows the epithelium and lam-
ina propria o± the buccal mucosa, which has a nonkeratinized
stratif ed squamous epithelium. There are many elastic f bers in
the lamina propria o± the mucosa. Elastic f bers appear pink and
do not readily stain with H&E stain. Fordyce spots (sebaceous-
like glands) may also be ±ound in the mucosa o± the cheek. They
increase with age and are more visible in elderly individuals.
The
lingual
and
inferior alveolar nerves
run through the pos-
terior groove o± the cheek (between the pterygomandibular
raphe and the ramus o± the mandible). This is an important
landmark ±or local anesthesia injections in the mouth.
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