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THE MASTICATORY

APPARATUS

B. L. Manion, Ph.D.

OBJECTIVES

Be able to describe the temporomandibular joint (TMJ).

Be able to describe the attachments, function, innervation and vascularization

of the muscles of mastication.

Be able to describe the oral cavity.

Be able to describe the structure and function of the tongue.

OBJECTIVES

Be able to describe the adult dentition.

Be able to describe the attachments, function, innervation and vascularization

of the muscles of the tongue.

Be able to describe the structure, function, innervation and vascularization

of the salivary glands.

THE TEMPOROMANBIBULAR JOINT

Body

Ramus

Coronoid process Head

Condyloid

process

Neck

Insertion of Temporalis M.

Angle

Insertion of Masseter M.

Sobotta, Atlas of Human Anatomy,

13th English Ed., version 1, CD-ROM

A modified hinge joint


Mental spine

Mandibular

foramen

Insertion of

Medial

Pterygoid M.

Entrance to

mandibular canal

Origin of Geniohyoid

and Genioglossus MM.

Mylohyoid line

Origin of Mylohyoid M.




Mandibular fossa

of temporal bone

Articular process

of temporal bone


Mandible

elevated,

mouth

closed

Mandibular

fossa

Head of

mandible

Articular

process


Mandibular

fossa

Articular

process

Head of

mandible

Mandible

depressed,

mouth

open


Fibrocartilaginous

Disc

Capsule

Divides joint space into

two separate cavities

Articular cartilage




Temporomandibular

ligament

Stylomandibular

ligament

A thickening in the capsule,

an intrinsic ligament




Sphenomandibular

ligament

Stylomandibular

ligament



MUSCLES OF MASTICATION

Temporalis m.

Masseter m.

Originates from floor

of temporal fossa and

temporal fascia and

inserts into coronoid

process and ramus of

mandible

Originates from zygomatic

arch and inserts into

external surface of angle of

mandible

COA5LWW


Temporalis m.

Retract

Elevate

Elevate

The elevation of the

mandible by the

temporalis and

masseter muscles

results in a

crushing of food

particles between

the teeth. the

retraction of the

mandible by the

temporalis muscle

reseats the head of

the mandible into

the mandibular

fossa.

COA5LWW


Medial pterygoid m.

Elevate

Originates from medial aspect

of lateral pterygoid plate and

inserts on inner surface of

mandibular angle




Medial pterygoid m. Medial pterygoid m.

O.

O.

I.

Medial

Masseter m. Masseter m.

Lateral Lateral

The lateral and medial

motions of the mandible

produced by the actions of

the masseter and medial

pterygoid muscles on

alternate sides results in a

grinding of food particles

between the cusps of the

teeth


The action of the

lateral pterygoid

muscles produces

protraction of the

mandible (an anterior

motion) resulting in the

sliding of the head of

the mandible forwards

and ending up inferior

to the articular

process. This process

is necessary to open

the mandible

O.

Protract

Originates from lateral surface of lateral

pterygoid plate and inserts on neck of the

mandible and the disc and capsule of the TMJ

Lateral pterygoid m.



ORAL CAVITY

Palatoglossal

arch

Soft palate

Hard palate

Uvula

Palatopharyngeal

arch

Palatine tonsil



ORAL CAVITY

Buccal cavity or

vestibule,

between the

cheeks and

gums laterally

and between

the lips and

teeth anteriorly

Oral cavity proper

Tongue

Floor Mylohyoid m.

Hard palate Food particle

held between

molars by the

coordinated

actions of the

tongue and

buccinator

muscle

Buccinator

m. (cheek

m.)



ORAL CAVITY

Oropharynx Oral cavity



THE TEETH

Distal

Vestibular

3 Molars

1 Canine

1+2+2+3 = 8 x 4 = 32

Lower right

quadrant

lower left

quadrant

2 Incisors

2 Bicuspids

Mesial

Oral



THE TEETH

Crown

Neck

Root

Alveolar bone of

maxillae or mandible

Pulp cavity

Dental

ligaments

Alveolar arteries and nerves Sobotta, Atlas of Human Anatomy,


THE TEETH

Inferior alveolar n.

Maxillary n.

(maxillary

division of

CN V)

Infraorbital n.

Superior

alveolar

nerves

Mandibular n.

(mandibular

division of CN V)



THE TONGUE

Pharyngeal tongue

(posterior 1/3rd)

Sulcus terminalis

Median furrow

Oral tongue

(anterior 2/3rds)

Palatoglossal fold

Lingual tonsil

Palatopharyngeal

fold

Circumvallate papillae

Palatine tonsil



THE TONGUE

Frenulum Sublingual papilla One or more ports for the submandibular gland



THE TONGUE

Hyoglossus m.

Palatoglossus m. (CN X)

Extrinsic muscles, all

innervated by

hypoglossal n. (CN XII)

except palatoglossus

Genioglossus m.

Styloglossus m.

originates from mental spine and

body of hyoid bone - inserts into

body of tongue - protrudes,

depresses and wags tongue side

to side

originates from

styloid process -

inserts into posterior

sides of tongue -

retrudes tongue and

elevates posterior

edges to form a

trough

originates from body and greater horn of hyoid

bone - inserts into posterior sides of tongue -

retrudes and depresses tongue

originates from soft palate -

inserts into posterolateral

body - elevates posterior

tongue or depresses soft

palate

Body of tongue comprised

of intrinsic muscles CN XII



THE TONGUE

Genioglossus m.

Transverse fibers

Longitudinal fibers

Intrinsic muscles, all

innervated by the

Hypoglossal Nerve (CN XII)



THE TONGUE

Sensory Innervation

Pharyngeal tongue -

posterior 1/3rd

General Sensory:

Glossopharyngeal N. (CN IX)

Special Sensory:

Glossopharyngeal N. (CN IX)

Oral tongue - anterior 2/3rds

General Sensory: Mandibular N. (V3)

via Lingual N.

Special Sensory: Facial Nerve

(CNVII) via Chorda Tympani N.



THE TONGUE

THE SALIVARY GLANDS

Parotid gland (CN IX)

Parotid duct

Buccinator m.

Accessory parotid

gland

Parotid duct

penetrating

buccinator m.

opposite the

upper 2nd molar



THE SALIVARY GLANDS

Submandibular gland (CN VII)

Mandible

Mylohyoid M.(V3)

Anterior belly of

digastric m. (V3)

Facial artery

Facial vein

Parotid gland

(CN IX)



THE SALIVARY GLANDS

Submandibular gland

Submandibular

duct

Sublingual

gland

Openings of

sublingual gland

Lingual n.

Sublingual papilla

Mylohyoid M.

Hyoid Bone Genioglossus

M. cut away

Medial Pterygoid

M. cut away



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