dr. nabil khouri md, phd
TRANSCRIPT
ORAL CAVITY II
Dr. Nabil Khouri MD, PhD
THE TONGUE
Mass of striated muscles covered with the mucous membrane
Divided into right and left halves by a median septum
Three parts:
Oral (anterior ⅔)
Pharyngeal (posterior ⅓)
Root (base)
Two surfaces:
Dorsal
Ventral
FUNCTIONS
The tonge is the most important
articulator for speech production.
During speech, the tongue can
make amazing range of
movements
The primary function of the
tongue is to provide a mechanism
for taste. Taste buds are located on
different areas of the tongue, but
are generally found around the
edges.
They are sensitive to
four main tastes: Bitter, Sour,
Salty & Sweet
DORSAL SURFACE
Divided into anterior two third and posterior one third by a V-
shaped sulcus terminalis.
The apex of the sulcus faces backward and is marked by a pit
called the foramen cecum
Foramen cecum, an embryological remnant, marks the site of the
upper end of the thyroglossal duct
Anterior two third: mucosa is rough, shows three types of
papillae:
Filliform
Fungiform
Vallate
Posterior one third: No papillae but shows nodular surface
because of underlying lymphatic nodules, the lingual tonsils
PAPILLAE
CIRCUMVALLATE
PAPILLAE are arranged
in a row parallel to and in
front of sulcus terminalis
FUNGIFORM PAPILLAE
are numerous at the tip
and margin of the tongue.
FILLIFORM PAPILLAE
are prevalent on the
dorsum of the tongue
arranged in rows parallel to
sulcus terminalis
VENTRAL SURFACE
Smooth (no papillae)
In the midline anteriorly, a mucosal fold, frenulum connects the tongue with the floor of the mouth
Lateral to frenulum, deep lingual vein can be seen through the mucosa
Lateral to lingual vein, a fold of mucosa forms the plica fimbriata
MUSCLES
The tongue is composed of two types of muscles:
Intrinsic
Extrinsic
The intrinsic M
Confined to tongue
No bony attachment
Consist of:
▫ Longitudinal fibers
▫ Transverse fibers
▫ Vertical fibers
• Function: Alter the shape of
the tongue
MUSCLES OF THE TONGUE INTRINSIC MUSCLES
MUSCLE FUNCTION
SUPERIOR
Shortens
tongue; curls
apex and sides
of tongue
INFERIOR Shortens
tongue; uncurls
apex and turns
it downward
TRANSVERSE Narrows and
elongates
tongue
VERTICAL Flattens and
widens tongue
All intrinsic muscles are supplied by Hypoglossal nerve
muscle Origion and insertion Action
Transverse muscle
From the median septum and pass lateraly to be inserted into the side of the tongue.
Narrow and elongate the tongue.
Superior Longitiudinal muscle
Attached to the mucus membrane over the posterior part of the tongue and run forward to attaches to the mucus membrane at its edges and tip.
Shorting the tongue and turn its tip and edges upwards.
Inferior longitudinal fibers
Situated lateral to genioglossus in the lower part of the tongue.
Shorten the tongue turn its tip and edges downwards.
Vertical fibers Run from the dorsum of the tongue to the mucus membrane on its ventral surface.
Flatten and broaden the tongue.
Intrinsic muscles
EXTRINSIC MUSCLES
Connect the tongue to the surrounding structures: the soft palate and the bones (mandible, hyoid bone, styloid process)
Include:
Palatoglossus
Genioglossus
Hyoglossus
Styloglossus Function: Help in movements of
the tongue
muscle Origion and insertion Action
Genioglossus From the upper mental spine of the mandible, its fiber run posteriorly upward and downward.
Aprotracture and depressor.
Hyoglossus From the superior border of the greater horn of the hyoid bone and passes vertically upward.
Depress the tongue.
Styloglossus From the anterior surface of the styloid processes run forward downward to enter the tongue below the insertion of the palatoglossus muscle.
Retractor of the tongue.
palatoglossus From the aponeurosis of the soft palate and descends to the tongue.
Raise the tongue to narrow the oropharyngeal isthmus.
Condroglossus From the lesser cornu of the hyoid and ascending to blend with the intrinsic lingual muscle.
Extrinsic muscles
MOVEMENTS
Protrusion:
Genioglossus on both sides acting together
Retraction:
Styloglossus and hyoglossus on both sides acting together
Depression:
Hyoglossus and genioglossus on both sides acting together
Elevation:
Styloglossus and palatoglossus on both sides acting together
SENSORY NERVE SUPPLY
Anterior ⅔:
General sensations: Lingual nerve
Special sensations : chorda tympani
Posterior ⅓:
General & special sensations: glossopharyngeal nerve
Base:
General & special sensations: internal laryngeal nerve
MOTOR NERVE SUPPLY
Intrinsic muscles:
Hypoglossal nerve
Extrinsic muscles:
All supplied by the hypoglossal nerve, except the palatoglossus
The palatoglossus supplied by the pharyngeal plexus
BLOOD SUPPLY
Arteries:
Lingual artery
Tonsillar branch of
facial artery
Ascending
pharyngeal artery
Veins:
Lingual vein,
ultimately drains into
the internal jugular
vein
Hypoglossal
nerve
Lingual
artery & vein
Deep lingual
vein
Dorsal lingual
artery & vein
LYMPHATIC DRAINAGE
Tip:
Submental nodes bilaterally & then deep cervical nodes
Anterior two third:
Submandibular unilaterally & then deep cervical nodes
Posterior third:
Deep cervical nodes (jugulodigastric mainly)
SPECIALIZED MUCOSA
• Covers the dorsum of the tongue.
• Occupies 15% of the oral cavity.
• Although it is masticatory mucosa by function but due to its high extensibility and lingual papillae, it is classified as
• “SPECIALIZED MUCOSA”.
Lingual Papillae:
These are the small nipple or hair–like structures on the upper surface of the
tongue that give the tongue its characteristic rough texture.
Four types of papillae are found on dorsum of the tongue:
1. Fungiform papillae
2. Filiform papillae
3. Foliate papillae
4. Circumvallate papillae
• Fungiform
Papillae:
fungus-like appearance
present on tip and sides of
tongue
scattered between filiform
papillae
smooth, rounded structures
covered by non-keratinized
epithelium
Appear red due to highly
vascular CT
Taste buds are present on the
superior surface
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Fungiform Papillae
• Filiform Papillae
Hair-like appearance
Cover entire anterior part of
tongue
Cone-shaped structures
covered by thick keratinized
epithelium
Form a tough surface
involved in compressing and
breaking food when tongue is
apposed to hard palate
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Filliform Papillae
• Foliate Papillae
Leaf-like appearance
Present on lateral margins of posterior part of tongue
Consist of parallel ridges that alternate with deep grooves in the mucosa
A few taste buds are present in their lateral walls
Circumvallate papillae Arranged anterior to sulcus terminalis 8-12
in number
Large structures surrounded by a deep, circular groove into which ducts of minor salivary glands (Glands of Ebner) open
Covered by keratinized epithelium on superior surface and non-keratinized epithelium on lateral surface
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Circumvallate Papilla and Taste buds (arrows)
TASTE BUDS
GINGIVA
Consists of dense vascular fibrous tissue which is covered by
mucuos membrane and attached to the alveolar margins of the
jaws.
Dorsal tongue. (a) The dorsal surface of the tongue is
covered by specialized mucosa. The roughness of the surface is
attributable to the abundant, small hair-like filiform papillae
that cover much of the anterior two- thirds of the tongue, and
lack taste buds. The less numerous, small, round, white-red,
papular fungiform papillae are distributed over the dorsal
surface (center of grey circles). On the most posterior one
third of the oral portion of the tongue are the 8 to 12 large
circumvallate papillae (arrows) that are lined up in a V-
formation and converge at the foramen cecum. (b) This view of
the dorsal tongue demonstrates the arrangement of
circumvallate papillae in a V-shaped configuration at the
junction of the anterior two-thirds and the posterior one-third
(arrows). (c) Taste buds (arrows) are present in the epithelium
of the lateral surfaces of the circumvallate papilla. (d) An
individual taste bud within the epithelium of the papillary
trough. The orifice (taste pore) (arrow) of the taste bud opens
into the lateral wall of the circumvallate papilla, allowing for
taste sensation to be received by the taste bud.
http://pocketdentistry.com/9-oral-mucosa-and-mucosal-sensation
SOFT PALATE
Attached to the posterior border of the hard palate
Covered on its upper and lower surfaces by mucous
membrane (Palatine Aponeurosis)
Composed of:
Muscle fibers
An aponeurosis
Lymphoid tissue
Glands
Blood vessels
Nerves
PALATINE APONEUROSIS Fibrous sheath
Attached to posterior border of hard palate
Is expanded tendon of tensor velli palatini
Splits to enclose musculus uvulae
Gives origin & insertion to palatine muscles
1. Uvula is the median conical projection marked by median raphe.
2. Palatine arches are free margins of the soft palate and splitting into two parts as they approach the lateral wall.
a. Palatoglossal arch or anterior pillar of fauces or anterior palatine arch encloses the palatoglossus muscle.
b. Palatapharyngeal arch or posterior pillar of fauces or posterior palatine arch encloses the palatopharyngeus muscle.
MUSCLES
Tensor veli palatini Origin: spine of sphenoid;
auditory tube
Insertion: forms palatine aponeurosis
Action: Tenses soft palate
Levator veli palatini Origin:petrous temporal bone,
auditory tube, palatine aponeurosis
Insertion: palatine aponeurosis
Action: Raises soft palate
Musculus uvulae Origin: posterior border of hard
palate
Insertion: mucosa of uvula
Action: Elevates uvula
MUSCLES
Palatoglossus
Origin: oral surface of
palatine aponeurosis
Insertion: side of tongue at
the junction of oral and
pharyngeal parts
Action: pulls root of tongue
upward, closes
oropharyngeal isthmus
Palatopharyngeus Origin: Ant Fasciculus-Post border of hard palate Post fasciculus-palatine aponeurosis
Insertion: posterior border of thyroid cartilage,
wall of the pharynx and its median raphe.
Action: Elevates wall of the pharynx
Non-Ketratinized stratified epith.
SENSORY NERVE SUPPLY Mostly by the maxillary nerve through its branches:
Greater palatine nerve
Lesser palatine nerve
Nasopalatine nerve
Glossopharyngeal nerve supplies the region of the soft palate
MOTOR NERVE SUPPLY
All the muscles, except tensor veli palatini, are
supplied by the:
Pharyngeal plexus
Tensor veli palatini supplied by the:
Nerve to medial pterygoid, a branch of
the mandibular division of the
trigeminal nerve
BLOOD SUPPLY
Branches of the
maxillary artery
Greater palatine
Lesser palatine
Sphenopalatine
Ascending palatine,
branch of the facial
artery
Ascending pharyngeal,
branch of the external
carotid artery