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Anatomy lec18
19-4-2011
Today's lecture is going to be about the mouth………
- The mouth extends between the lips to the oropharyngeal isthmus.
-there are two pillars that constitute the mouth:
a-palatoglossal(separates the oral from the pharyngeal)
b-palatopharengeal
parts of the mouth:
- separated by upper and lower dental arches into:
a-outer oral vestibule: horseshoe shaped between dental arches and the inner surface of
the lips..
b-oral cavity proper(it's the cavity that's in during occlusion)
Oral mucosa of the mouth:
-The oral mucosa of the mouth is formed by stratified squamous epithelium.
-The oral mucosa is divided into three parts:
a-lining mucosa: which covers the floor of the mouth, lines the cheecks,the lips and
the soft palate…..it's thin, soft ,fragile,pliable and non keratinized.
b-masticatory mucosa: It covers the hard palate and the gingiva,it comes in primary
contact with food….it is thickly keratinized and has to do with the resistance of wear and
tear.
c-specialized mucosa: it covers the surface
of the tongue….. largely covered by cornified
papillae,so it is sensitive.
Boundries:
-lateral :cheeks(buccinator muscle on the outside
of this muscle is skin and in the inside it is lined by
mucosa)
-roof: hard palate and soft palate.
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-floor>>>>>>from superior to inferior:
.tongue
.submandibular gland(posterior)
.sublingual gland(anterior)
.mylohyoid muscle(mascualr diaphragm)
.geniohyoid
Tongue
-the tongue is a mascular organ,covered
by mucosa on both its ventral and its
dorsal surfaces and has a tip.
- The dorsum of the tongue is divided by a
V shaped sulcus terminalis into two parts
which differ in their development, their
structure and nerve supply:
a- oral part: which forms the anterior
2/3….called the body.
b-pharyngeal part: forms the posterior
1/3……called the root.
-there is a foramen at the tip of sulcus
terminalis called foramen cecum…which is
a remnant of thyroglossal duct.
-the tongue is formed of two halfs;right and left which are united by an intermediate
septum.
Ventral part:covered by thin mucosa that is attached loosely into the floor of the mouth by a
frenulum(which sometimes is not separated causing a condition called tongue tie preventing
speech).
-lingual vein,artery and nerve(van) can be seen easily on both sides of frenulum…and they
are superficial to ventral aspect.because of high absorption of this area vasodilator dugs are
put there(for angina pectoris).
Muscles of the tongue:
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1-intrensic muscles: which alter the shape of the tongue while inside the oral cavity….for
example flattening the tongue.
2-extrensic muscles:come from outside of the oral cavity…..which move the tongue:
a-genioglossus:originates from superior mental spine which forms most of the body of the
tongue.
b-hyoglossus:quadrangular in shape,depresses the tongue during swallowing.
c-styloglossus:from styloid to posterior aspect of the tongue….it retracts and elevates.
d-palatoglossus:last part of swallowing.
-They are all innervated by Xll (hypoglossal nerve)…except for palatoglossal which is supplied
by pharyngeal plexus via vagus nerve(lateral side of middle constrictor of pharynx).
-Arterial supply: from the lingual artery which branches from ECA,which originates above the
greater horn of hyoid, dive deep to hyoglossus,then to the floor of the oral cavity, then
upward to supply the tongue+sublingual+submandibular,external to it is the mylohyoid
muscle.
-veins: will go to the internal jagular vein.
1-dorsal lingual vein>>>follows the lingual artery.
2-deep lingual vein>>>on both sides of the frenulum accompanying CN Xll>>>>lateral to
hyoglossus.
Nerve supply:
-sensory innervation:
.which is for the mucosa
-general sensation fot anterior 2/3 by lingual nerve.
-special sensation by chorda tempani.
-poserior 1/3 and the circumvallate papillae >>>>>both special and general by
glossopharyngeal nerve..
-vallicula+anterior surface of epiglottis(responsible for gag reflex)>>>>internal
laryngeal(from vagus) .
Gateway into floor of the oral cavity:
-it is a triangular space formed between the free posterior border of the mylohyoid and the
superior and middle constrictor muscles of the pharynx.
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-it is called a gateway because it transmits structures from and into the mouth.
-Its contents are associated with the tongue.
1-muscles:hyoglossus,styloglossus.
2-Vessels:lingual artery,lingual vein.
3-Nerves:lingual nerve,glossopharyngeal nerve,hypoglossal nerve.
4-oral part of the submandibular gland.
5-lymphatics.
Floor of the mouth from superior to inferior:
1-mucosa
6-hyoglossus
2-submucosa
3-lingual nerve 4-deep part of submandibular 5-duct
7-genioglossus
Arterial supply of the teeth:
-all upper teeth are supplied by anterior(superior+middle+inferior)alveolar arteries which
branch from third part of maxillary artery.
-lower teeth are supplied by inferior alveolar artery which branches from first part of
maxillary artery.
Nerve supply of upper teeth:
1-incisors+canines>>>>>>anterior superior alveolar nerve
2-premolars+buccal root of first molar>>>>>middle superior alveolar nerve.
3-molars except for buccal root of first molar are supplied >>>>.posterior superior alveolar
nerve.
Nerve supply of maxillary buccal gingiva:
1-incisors+canines>>>>>>anterior superior alveolar nerve
2-premolars >>>>>middle superior alveolar nerve.
3-molars >>>>>>.posterior superior alveolar nerve.
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Nerve supply of maxillary palatel gingival:
1-incisors+canines>>>>nasopalatine from maxillary nerve.
2-premolar+molars>>>>>>>greaterpalatine from decending palatine via maxillary nerve.
Nerve supply of lower teeth:
1-incisors+canines+first premolar>>>>>incisive branch
2- second premolar+molars>>>>>>main trunk
Nerve supply of mandibular buccal gingiva:
1-incisors+canines+premolars>>>>>>mental nerve
2-molars>>>>>>>buccal nerve
Nerve supply of mandibular lingual gingiva:
-all by lingual nerve.
Dedicated to:
1-nadya damanhori:D
2-shelet eli elo sheleh:P:P
-Plz forgive me if there are any mistakes:D
Done by:Dana Hamdan