The oral cavity has walls, a roof, and floor that form its boundaries. It has two openings - the oral fissure anteriorly and the oropharyngeal isthmus posteriorly. The oral cavity is separated into the oral vestibule and oral cavity proper by the upper and lower dental arches. The walls include the cheeks, which are made of skin, muscle and oral mucosa. The floor is formed by the mylohyoid and geniohyoid muscles and the tongue. The tongue has various papillae and is composed of intrinsic and extrinsic muscles that aid in movement and functions like speech and swallowing. Blood vessels like the lingual artery supply the tongue.

1. ORAL CAVITY
Walls:
Roof
Floor
Lateral walls
Opennings
Oral fissure:
anterior opening
Oropharyngeal
isthmus:
Posterior, opens
into the oral part
of the pharynx

2. Separated by the upper
and lower dental arches
into:
Oral vestibule:
(outer),horseshoe-
shaped, between the
dental arches and the
deep surfaces of the
cheeks and lips
Oral cavity proper:
(inner), which is enclosed
by the dental arches.
ORAL CAVITY

3. Walls: the cheeks
Fascia and a layer of
skeletal muscle sandwiched
between skin externally and
oral mucosa internally.
Skeletal muscle within the
cheeks is the Buccinator
muscle
Joined to the anterior margin
of the superior constrictor
muscle by the
pterygomandibular raphe,
Between the tip of the
pterygoid hamulus of the
sphenoid bone and a
roughened area of bone
immediately behind the last
molar tooth on the mandible

4. Floor
Formed by three
structures:
Muscular diaphragm:
fills the U-shaped gap
between the left and
right sides of the body
of the mandible
composed
Mylohyoid
muscles
Geniohyoid muscles
Tongue, which is
superior to the
geniohyoid muscles.

5. Origin: Mylohyoid line of body of mandible
Insertion: Body of hyoid bone
NS: Inferior alveolar nerve
Action: Elevates floor of mouth and hyoid bone or depresses
mandible
Mylohyoid

6. Geniohyoid
Origin: Inferior mental
spine of mandible
Insertion: Body of hyoid
bone
NS: C1 nerve
Action: Elevates hyoid
bone or depresses
mandible

7. The tongue
Muscular structure
Floor of the oral
cavity
Anterior wall of
the oropharynx
Apex: anterior part
(triangular), directed
anteriorly and sits
behind the incisor
teeth.
Root: attached to
the mandible and
the hyoid bone
Pharyngeal
surface: lingual
tonsil

8. Tongue
Papillae: projections of
the lamina propria
covered with stratified
squamous epithelium.
(The dorsal and lateral
surfaces of the tongue).
1) Fungiform papillae:
mushroom like
elevations (red dots)
Dorsum of the tongue,
concentrated mainly
around the margins and
tip of the tongue
most of them contain
taste buds
2) Vallate (circumvallate) papillae: About 12 in number
Arranged in an inverted V-shape on the posterior surface of the tongue.
All of them contain taste buds.

9. Tongue
3) Foliate papillae:
On the lateral margins
of the tongue, but
most of their taste
buds degenerate in
early childhood.
4) Filiform papillae:
pointed, threadlike
projections
over the anterior two-
thirds of the tongue.
have a keratinized
surface
lack taste buds,
contain receptors for
touch and increase
friction between the
tongue and food.

10. Inferior surface of
tongue
Lacks papillae
Frenulum of
tongue: single
median fold
continuous with the
mucosa covering the
floor of the oral
cavity,
On each side of the
frenulum is a lingual
vein, and lateral to
each vein is a rough
fimbriated fold.
Ankyloglossia?

11. Tongue
Divided into symmetrical lateral halves by a median septum
Two groups of muscles
Intrinsic muscles: originate in and insert into connective tissue within the
tongue. Include: Superior longitudinal, inferior longitudinal, transvers, and
vertical muscles.
Extrinsic muscles: originate outside the tongue and insert into connective
tissues in the tongue. Include: hyoglossus, genioglossus, and styloglossus
muscles

12. Intrinsic muscles of the tongue
Superior longitudinal:
Origin: Submucosal connective tissue at the back of the tongue and from
the median septum of the tongue
Insertion: submucosal connective tissue and mucosa on margins of tongue
NS: Hypoglossal nerve
Action: Shortens tongue; curls apex and sides of tongue

13. Intrinsic muscles of the tongue
Inferior longitudinal:
Origin: Root of tongue
Insertion: Apex of tongue
NS: Hypoglossal nerve
Action: Shortens tongue; uncurls apex and turns it downward

14. Intrinsic muscles of the tongue
Transverse:
Origin: Median septum of tongue
Insertion: Submucosal connective tissue on lateral margins of tongue
NS: Hypoglossal nerve
Action: Narrows and elongates tongue

15. Intrinsic muscles of the tongue
Vertical:
Origin: Submucosal connective tissue on dorsum of tongue
Insertion: Connective tissue in more ventral regions of tongue
NS: Hypoglossal nerve
Action: Flattens and widens tongue

16. Genioglossus:
Origin: Superior
mental spines
Insertion: Body of
hyoid; entire
length of tongue
NS: Hypoglossal
nerve
Action: Protrudes
tongue; depresses
center of tongue
Extrinsic muscles of the tongue

18. Hyoglossus:
Origin: Greater
horn of hyoid
Insertion: Lateral
surface of tongue
NS: Hypoglossal
nerve
Action: depresses
tongue
Extrinsic muscles of the tongue

19. Styloglossus:
Origin: Styloid
process
Insertion: Lateral
surface of tongue
NS: Hypoglossal
nerve
Action: retracts
tongue
Extrinsic muscles of the tongue

20. Palatoglossus:
Origin: Inferior
surface of
Palatine
aponeurosis
Insertion:
Lateral margin of
tongue
NS: pharyngeal
branch of vagus
Action:
Depresses
palate; moves
palatoglossal
arch toward
midline; elevates
back of the
tongue
Extrinsic muscles of the tongue

21. Hyoglossus,
styloglossus,
lingual artery and
vein, lingual nerve,
hypoglossal nerve,
glossopharyngeal
nerve
Triangular aperture

22. Loops
downward and
forward to pass
deep to the
hyoglossus
muscle
Enters the floor
of the oral
cavity. travels
forward in the
plane between
the hyoglossus
and
genioglossus
muscles to the
apex of the
tongue.
Lingual artery

23. Separated from
the arteries
posteriorly by the
hyoglossus
muscles.
Travels with the
hypoglossal nerve
on the external
surface of the
hyoglossus
muscle
Dorsal lingual
vein:
follows the lingual
artery between
the hyoglossus
and genioglossus
Deep lingual vein