THE MOUTH

MOUTH

Extends from the lips to the oropharyngeal isthmus (the junction of the mouth with the pharynx).

SUBDIVIDED INTO:

Vestibule

- Lies between the teeth and cheeks externally and the gums and teeth internally

- slit-like space that communicates with the exterior through the oral fissure

Mouth Cavity Proper

VESTIBULE

Superiorly and inferiorly, limited by:Mucous membrane

from the lips and cheeks onto the gums

Laterally:Cheeks (buccinator) opposite upper 2nd

molar - opening of the parotid duct

MOUTH CAVITY PROPER

Lies within the alveolar arches, gums, and teeth.

Roof: hard palate in front and the soft palate behind

Floor: anterior two-thirds of the tongue and by the reflection of the mucous membrane from the sides of the tongue to the gum on the mandible.

MOUTH CAVITY PROPER

Midline: fold of mucous membrane (frenulum of the tongue) connects the undersurface of the tongue to the floor of the mouth

On each side is a papilla containing the orifice of the submandibular duct

Rounded ridge of mucous membrane extending laterally from the papilla, sublingual fold

SENSORY NERVE SUPPLY OF THE MUCOUS MEMBRANE OF THE MOUTH

ROOF is supplied by the greater palatine and nasopalatine nerves (maxillary nerve)

FLOOR is supplied by the lingual nerve (mandibular nerve) closely related to the lower 3rd molar

CHEEK is supplied by the buccal nerve (mandibular nerve)

TEETH

There are two sets of teeth, which make their appearance at different times of life. The first set, called the DECIDUOUS TEETH, is

temporary.The second set is called the PERMANENT

TEETH.

TEETH

Deciduous teethAre 20 in number.They begin to erupt at about 6 months after

birth and have all erupted by the end of the 2nd year of life.

Composed of:4 incisors2 canines4 molars

TEETH

Eruption of deciduous teeth:Central Incisors 6-8 monthsLateral Incisors 6-10 monthsFirst Molars 1 year oldCanines 18 monthsSecond Molars 2 years teeth of the lower jaw usually appear

earlier

TEETH

Permanent teethAre 32 in numberThey begin to erupt at the sixth year. However,

the last tooth to erupt is the third molar, and this may take place between 17th and 30th years.

TEETH

Composed of:4 incisors2 canines4 premolars6 molars

TEETH

Eruption of permanent teeth:First molar 6 yearsCentral incisors 7 yearsLateral incisors 8 yearsFirst premolars 9 yearsSecond premolars10 yearsCanines 11 yearsSecond molars 12 yearsThird molars 17-30 years Teeth of the lower jaw appear earlier

TONGUE

Is a mass of striated muscle covered with mucous membrane.

Its anterior 2/3 lies in the mouthIts posterior 3rd lies in the pharynx

muscles attach the tongue to the styloid process and the soft palate above and to the mandible and the hyoid bone below

TONGUE

Fibrous septumDivides the tongue into

right and left halves.Also known as median

sulcus

Sulcus terminalis V-shaped sulcus that divides the mucous

membrane of the upper surface of the tongue to anterior and posterior parts.

This sulcus serves to divide the tongue into anterior two-thirds, or oral part, and posterior third, or pharyngeal part.

MUCOUS MEMBRANE OF THE TONGUE

Foramen cecum small pit that marks

the apex of the sulcus Is an embryological

remnant and marks the site of the upper end of the thyroglossal duct

TYPES OF PAPILLAE

FILIFORM papillaeFUNGIFORM papillaeVALLATE papillae

posterior 3rd of tongue is devoid of papillae but has a nodular irregular surface due to the lingual tonsil

TYPES OF PAPILLAE

FiliformVery numerous and cover the anterior two-

thirds of the tongue on the upper surfaceThey form small conical projections and are

whitish in color due to the thickness of the cornified epithelium.

Contains no taste buds

TYPES OF PAPILLAE

FungiformLess numerous than filiform papillaeAre scattered on the sides and at the apex of

the tongueMushroom shaped and possess a vascular

connective tissue core, which imparts a reddish tinge to the papillae

Perceives sweet and salty taste

TYPES OF PAPILLAE

Vallate papillaeAre 10-12 in number and are situated in a row

immediately in front of the sulcus terminalisEach papillae measures about 2mm in diameter

and protrude slightly from the surface.Surrounded by circular furrow, inside are the

taste buds.Bitter taste

TYPES OF PAPILLAE

Foliate Perceives sour tasteFound on the tongue

margin at the junction of the body and root

Frenulum of the tongue the lingual vein can be

seen lateral to the frenulum

lateral to the lingual vein, the mucous membrane forms a fringed fold called the plica fimbriata

MUSCLES OF THE TONGUE

2 TYPES:IntrinsicExtrinsic

MUSCLES OF THE TONGUE

Intrinsic musclesAre confined to the tongue and are not attached

to the bone.They consist of longitudinal, transverse, and

vertical fibers.Nerve supply: hypoglossal nerveAction: they alter the shape of the tongue

MUSCLES OF THE TONGUE

Extrinsic musclesAre attached to the bones and the soft palate.

GenioglossusHyoglossusStyloglossusPalatoglossus is associated with the soft palate

Muscle Origin Insertion Nerve supply

action

Intrinsic Muscles

Longitudinal Median septum & submucosa

Mucous membrane Hypoglossal nerve

Alters shape of tongue

Transverse

Vertical

Extrinsic Muscles

Genioglossus mandible Blends w/ other muscles of tongue

Hypoglossal nerve

Protrudes apex of tongue

Hyoglossus Hyoid bone Depresses tongue

Styloglossus Styloid process Draws tongue upward and backward

Palatoglossus Palatine aponeurosis

Side of tongue Pharyngeal plexus

Pulls roots of tongue upward and backward, narrows oropharyngeal isthmus

BLOOD SUPPLY

Is supplied by:Lingual arteryTonsillar branch of facial arteryAscending pharyngeal artery

Veins drain into the internal jugular vein

LYMPH DRAINAGE

Tip of the tongue drains into the submental lymph nodes.

The remainder of the anterior 2/3 of the tongue drains into the submandibular and deep cervical lymph nodes on both sides

Lymph from the posterior 3rd of the tongue drains into the deep cervical lymph nodes on both sides

SENSORY INNERVATION

The mucous membrane covering the anterior 2/3 of the tongue is supplied by the lingual nerve for general sensation

Taste fibers from the anterior 2/3 of the tongue, excluding vallate papillae, run in the chorda tympani branch of the facial nerve

General sensation and taste from the posterior 3rd of the tongue including the vallate papillae are served by the glossopharyngeal n.

MOVEMENTS

ProtrusionMay be brought about by the genioglossus

muscles on both sides acting together

RetractionIs produced by the styloglossus and by the

hyoglossus muscles on both sides acting together

MOVEMENTS

DepressionProduced by the hyoglossus and the

genioglossus muscles on both sides acting together

Retraction and ElevationIs produced by the styloglossus and

palatoglossus muscles on both sides acting together.

The shape of the tongue is modified by the intrinsic muscles

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