Transcript 19. oral cavity by girls antomy teame2010-10

The Mouth
The mouth cavity is divided into
vestibule & mouth cavity proper.
 Vestibule of mouth lies between lips
+ cheeks (buccinator) externally, /and
gums + teeth internally.
.
The mouth cavity proper :
Boundaries :
1-In front and at the sides : gums & teeth
2- Roof : hard palate in front & soft
palate behind.
3- Floor : anterior 2/3 of tongue &
sublingual region.
4-Posteriorly : mouth communicates with
oropharynx by oropharyngeal isthmus.
The cheek forms the lateral wall of the
vestibule and is made up of the buccinator
muscle, which is covered on the outside by
fascia and skin and is lined by mucous
membrane.
The parotid duct opens at the
vestibule of mouth opposite upper 2nd
molar tooth.
Sublingual Region : lies in the floor of
mouth below tongue, contains :
1-The frenulum of the tongue is a fold of
mucous membrane in the midline connects
undersurface of tongue to floor of mouth.
2-Duct of submandibular gland opens on
each side of frenulum.
3Sublingual gland is covered by m.m called
sublingual fold, which extends laterally on
both sides from lower part of frenulum, and
sublingual ducts open by many aperatures
on its summit.
Sensory nerve supply of mucous
membrane of mouth :
• Roof (palate) : greater palatine & Nasopalatine
nerves from Maxillary N.
• Floor (anterior 2/3 of tongue) : lingual N. of
mandibular N. (general sensation), +
chorda tympani N. of facial N. (taste sensation).
• Cheek : buccal nerve, a branch of mandibular N.
The Tongue
It is a mass of striated
muscle covered with mucous
membrane.
Its anterior 2/3 lies in
mouth (oral part), while
posterior 1/3 lies in pharynx
(pharyngeal part).
It is divided into right &
left halves by a median
fibrous septum.
The Tongue
Mucous membrane of the Upper
surface of tongue (dorum of
tongue)
--Oral & pharyngeal parts are separated by
a V-shaped groove called sulcus terminalis,
the apex of sulcus is marked by a pit called
foramen coecum ( is an embryologic
remnant of upper end of thyroglossal
duct).
--The
mucous membrane of oral part
(anterior 2/3) contains vallate papillae.
--The mucous membrane of
pharyngeal part (post.1/3) devoid of
papillae, but it has a nodular irrigular
surface caused by underlying lymph
nodules (lingual tonsils in submucosa).
The Tongue
Mucous membrane of inferior
surface of the tongue :
-- The mucosa is smooth.
-- In the midline, it is connected
to the floor of mouth by a fold of
m.m. called frenulum of tongue.
-- On lateral side of frenulum,
deep lingual vein lies in
submucosa, can be seen through
the mucosa. But Lingual N. &
lingual artery run at deeper plane
from mucosa.
-- Lateral to vein, a serrated fold
of mucosa is seen ‘plica
fimbriata’
Innervation of the Tongue :
(vagus)
Motor Nerves :
-- All intrinsic & extrinsic muscles are
supplied by hypoglossal N. EXCEPT
palatoglossus is supplied by
pharyngeal plexus via vagus N.
Sensory Nerves :
1-Anterior 2/3 : general sensations : by
lingual N….taste sensations (excluding
vallate paoillae) : by chorda tympani.
2-Posterior 1/3, including vallate
papillae : general & taste sensations by
glossopharyngeal N.
3-Root of tongue ( most posterior part)
: internal laryngeal branches of vagus.
Blood Supply of Tongue
• Lingual artery : branch of external carotid artery, it supply
most of tongue (the main arterial supply)
• Tonsillar (branch of facial) + Ascending pharyngeal artery
(branch of ext.carotid artery) : they supply posterior part of
tongue.
• Veins of tongue form lingual vein ,which drains into internal
jugular vein.
Lymph Drainage of Tongue
Tip of tongue : drain into
submental L.Ns.
The remainder of anterior
2/3 of tongue : drains into
submandibular + inferior deep
cervical L.Ns.
Posterior 1/3 of tongue :
drains into superior deep cervical
L.Ns.
Muscles of Tongue
• Intrinsic muscles :
-They are not attached to bone.
-They consist of longitudinal, transverse
& vertical fibers (inside the tongue).
-Origin : median septum & submucosa.
-Insertion : mucous membrane.
-Nerve supply : hypoglossal N.
-function : Alter the shape of tongue.
Extrinsic Muscles of Tongue
Extrinsic muscles :
-They connect tongue to styloid
process & soft palate above, /and to mandible & hyoid bone
below.
-They are :
1-Genioglossus.
2-Hyoglossus.
3-Styloglossus.
4-palatoglossus.
Extrinsic Muscles of Tongue
Genioglossus :
-Origin : superior mental
tubercle of mandible.
-Insertion : it is fan-shaped,
blends with other muscles
of tongue (into tongue, &
body of hyoid bone).
-Action :
-The 2 muscles : protrude
tip of tongue through
mouth.
-One muscle : protrudes the
tongue to opposite side.
Extrinsic Muscles of Tongue
Hyoglossus :
-Origin : body + greater cornu of
Hyoid bone.
-Insertion : it is quadrilateral,
runs upward deep to mylohyoid
muscle to insert at side of
post.part of tongue.
Action :
Depress tongue and increase
mouth cavity during swallowing.
Structures Superficial to Hyoglossus
Superficial relations :
1-Mylohyoid + Styloglossus.
2-Lingual N.
3-Hypoglossal N.
4-Submandibular ganglion.
5-Deep part of submandibular gland.
 ligual artery (deep to hyoglossus)
Extrinsic Muscles of Tongue
Styloglossus :
-Origin : styloid process.
-Insertion :blends with other
muscles of tongue.(whole length
of side of tongue).
-Action :
Pulls tongue upward and
backward (retraction + elevation)
during swallowing.
It passes between superior &
middle constrictors of pharynx to
reach tongue.
Extrinsic Muscles of Tongue
Palatoglossus :
-Origin : from undersurface of
palatine aponeurosis (soft palate).
-Insertion : into the side of post.1/3
of tongue.
-Action : pulls root of tongue
upward & backward, (retraction +
elevation), so narrows
oropharyngeal isthmus and
prevents regurgitation of food.
Movements of Tongue
Protrusion : genioglossus on
both sides acting together.
Retraction : styloglossus +
hyoglossus Ms. on both sides.
Depression : hyoglossus +
genioglossus Ms. on both sides.
Retraction & elevation of
posterior 1/3 of tongue :
Styloglossus + Palatoglossus,
on both sides.
The Palate
It forms the roof of mouth.
It is divided into : hard palate
anterior & soft palate posterior.
Hard palate :
-It forms anterior 2/3 of palate.
-it is formed by palatine processes
of maxillae + horizontal plates of
palatine bones.
-It is bounded laterally by alveolar
arches and continuous behind with
soft palate.
-It forms floor of nasal cavities.
–It is covered with mucoperiosteum.
Soft Palate
It forms the posterior 1/3 of
palate.
It is a mobile fold attached
anteriorly to the hard palate.
Soft palate
Its posterior free end forms
a conical projection in the
midline called the Uvula.
It lies between the naso pharynx & oropharynx.
Laterally , it is attached to
side wall of pharynx.
Structures of Soft Palate
Mucous Membrane : covers
its upper & lower surfaces.
Palatine aponeurosis
Palatine aponeurosis :
it is a fibrous sheet in the
middle, attached to posterior
border of hard palate, it is the
expanded tendon of Tensor
veli palatini on both sides.
Muscles of Soft Palate :
1-Tensor vili palatini.
2-Levator vili palatini.
3-Palatoglossus.
4-Palatopharyngeus.
5-Musculus uvulae.
Muscles of Soft Palate
Tensor veli palatini :
-Origin : spine of sphenoid +
auditory tube.
-Insertion :with muscle of other
side forms palatine aponeurosis
which is inserted into palatine
crest (posterior border of hard
palate).
–N.supply : N. to medial
perygoid from mandibular N.
-Action : tense soft palate.
Muscles of Soft Palate
Levator veli palatini :
-Origin : Petrous part of temporal bone +
auditory tube.
-Insertion : palatine aponeurosis.
- N.supply : pharyngeal plexus.
-Action : elevates soft palate, shutting off
nasopharynx fron oropharynx in swallowing.
Palatopharyngeus :
-Origin : palatine aponeurosis.
-Insertion : posterior border of thyroid
cartilage+ wall of pharynx. It lies in a fold of
m.m of lateral wall of pharynx, called
palatopharyngeal arch.
-N.supply : pharyngeal plexus.
-Action : The 2 muscles elevate wall of
pharynx + closing of ‘‘pharyngeal isthmus’’
during swallowing (communicating channel
between nasal & oral parts of pharynx).
Muscles of Soft Palate
Palatoglossus :
-Origin : palatine aponeurosis.
-Insertion : side of post.1/3 of tongue,
it lies in a fold of m.m. of lateral wall
of oro-pharynx, called palatoglossal
arch, which lies in front of palatine
tonsile.
-N.supply : pharyngeal plexus.
-Action : the 2 muscles pull root of
tongue upward & backward, causing
narrowing of ‘oropharyngeal isthmus’
and prevent regurgitation of food.
Musculus uvulae :
Origin : posterior border of hard palate (post.
Nasal spine).
-Insertion : m.m.of uvulae.
N.supply : pharyngeal plexus.
Action : elevates uvulae.
palatoglossal & palatopharyngeal
arches : are folds of mucous
membranes covering the muscles of
sot palte, palatoglossus &/
palatopharyngeus in the oropharynx.
Oropharyngeal isthmus :
it is a sphincter between mouth &
oral part of pharynx, and it is
marked by the interval between 2
palatoglossal arches.
Pharyngeal isthmus :
it is the opening between the free
end of soft palate & posterior wall of
pharynx
( communication between the nasal
and / oral parts of pharynx)
Innervations of Soft Palate
• Motor : all palatine muscles are supplied by
pharyngeal plexus EXCEPT tensor veli palatini.
(by N.to medial pterygoid from mandibular N.).
• Sensory :
1- Greater & Lesser palatine Ns. of maxillary,
2- Nasopalatine N. of maxillary N.
Blood Supply & Lymph Drainage of soft Palate :
•
•
•
•
•
Greater palatine from maxillary artery.
Ascending palatine from facial artery.
Ascending pharyngeal artery from external carotid artery.
Veins of palate : end in pterygoid & tonsillar venous plexus.
Lymph vessels of palate : end in deep cervical L.Ns.