The document describes the anatomy of the temporal region and muscles of mastication. It discusses the boundaries and contents of the temporal fossa and infratemporal fossa. It then describes the four muscles of mastication - the temporalis, masseter, medial pterygoid, and lateral pterygoid muscles. Finally, it details the temporomandibular joint, including its movements, ligaments, and important relations.

1. Anatomy of temporal region and
muscles of mastication
Dr. Mohammed Mahmoud Mosaed

2. Lateral side of the skull
• The lateral side of
the skull can be
divided into an
upper temporal
fossa and a lower
infratemporal fossa,
separated by the
zygomatic arch.

3. The temporal fossa
• The temporal fossa is the fan shaped space on the
lateral side of the skull above the zygomatic arch
• Boundaries
• Inferiorly: by the zygomatic arch and it is continuous
with the infratemporal fossa deep to the zygomatic
arch
• Superiorly and posteriorly: by the temporal lines
• Anteriorly: by the posterior surface of the frontal
process of the zygomatic bone and the posterior
surface of the zygomatic process of the frontal bone
• Laterally: by the temporal fascia, which is overlying the
temporalis muscle

6. The floor of the temporal fossa
• The floor of the temporal fossa is formed by the
frontal and parietal bones superiorly and the greater
wing of the sphenoid and squamous temporal
inferiorly.
• All four bones of one side meet at an H-shaped sutural
junction termed the pterion.
• This is an important anthropometric landmark as it
overlies both the anterior branch of the middle
meningeal artery and the lateral fissure of the cerebral
hemisphere.
• The pterion corresponds to the site of the
anterolateral (sphenoidal) fontanelle of the neonatal
skull which closes in the third month after birth

8. Temporal lines
• The superior and
inferior temporal lines
arch across the skull
from the zygomatic
process of the frontal
bone to the
supramastoid crest of
the temporal bone.
• The superior temporal
line gives attachment to
the temporal fascia
while the inferior
temporal line provides
attachment for
temporalis.

9. Contents of temporal fossa
• Temporalis muscle
• Zygomaticotemporal
nerves
• Deep temporal nerves
• Deep temporal artery

10. The temporalis muscle
• The temporalis muscle is a large fan-shaped muscle
that fills much of the temporal fossa.
• Origin: from the bony surfaces of the fossa and the
temporal fascia.
• Insertion: on the coronoid process of the mandible
• The more anterior fibers are oriented vertically while
the more posterior fibers are oriented horizontally.
• Action: Temporalis is a powerful elevator of the
mandible and it’s posterior fibers retracts the
mandible.
• Nerve supply: deep temporal branches of the
mandibular nerve
• Blood supply: Deep temporal arteries

13. Muscles of mastication

14. Muscles of mastication
• The muscle of mastication are the muscles that
move the mandible and act on the
tempromandibular joint
• There are 4 muscles of mastication:
• Temporalis muscle
• Masseter muscle
• Medial ptergoid muscle
• Lateral ptergoid muscle

15. Masseter muscle
• Origin: lower border and
medial surface of
zygomatic arch
• Insertion: lateral surface of
the ramus of the mandible
• Action: elevation of the
mandible
• Nerve supply: nerve to
masseter from the anterior
division of the mandibular
nerve

16. The medial pterygoid muscle
• The medial pterygoid muscle has
deep and superficial heads.
• Origin: The deep head from the
medial surface of the lateral
pterygoid plate.
• The superficial head from the
tuberosity of the maxilla.
• Insertion: Inserted to the
roughened medial surface of the
ramus of mandible near the angle.
• Action: it elevates the mandible,
also it assists in protruding the
lower jaw.
• Nerve supply: by the nerve to
medial pterygoid from the
mandibular nerve

17. The lateral pterygoid
• The lateral pterygoid is a thick triangular
muscle and has two heads: upper and lower
heads
• Origin: The upper head from the
infratemporal surface of the greater wing of
sphenoid
• The lower head from the lateral surface of the
lateral pterygoid plate.
• Insertion: into the pterygoid fovea of the
neck of mandible and to the articular disc of
temporomandibular joint.
• Action: it open the mouth by pully the
mandible forward onto the articular tubercle
and is therefore the major protruder of the
lower jaw.
• Nerve supply: by the nerve to lateral
pterygoid from the mandibular nerve

19. Muscles of mastication

20. Temporomandibular Joint
• Articulation
• The articular tubercle and the anterior portion of the mandibular fossa of
the temporal bone above
• The head (condyloid process) of the mandible below.
• The articular surfaces are covered with fibrocartilage.
• Type of Joint
• It is synovial. The articular disc divides the joint into upper and lower
cavities.
• Capsule
• The capsule surrounds the joint and is attached above to the articular
tubercle and the margins of the mandibular fossa and below to the neck
of the mandible.
• Synovial Membrane
• This lines the capsule in the upper and lower cavities of the joint.
• Nerve Supply
• Auriculotemporal and masseteric branches of the mandibular nerve

21. • The articular disc
• Divides the joint into upper and lower cavities.
• It is attached circumferentially to the capsule and
to the tendon of the lateral pterygoid muscle .
• The disc moves forward and backward with the
head of the mandible during protraction and
retraction of the mandible.
• The upper surface of the disc is concavoconvex
from before backward and the lower surface is
concave

23. Ligaments
• The lateral temporomandibular ligament
• Its fibers run downward and backward from the
tubercle on the root of the zygoma to the lateral
surface of the neck of the mandible.
• The sphenomandibular ligament
• lies on the medial side of the joint. It is attached
above to the spine of the sphenoid bone and below
to the lingula of the mandibular foramen.
• The stylomandibular ligament
• It is thickened band of deep cervical fascia that
extends from the apex of the styloid process to the
angle of the mandible.

24. Temporomandibular joint as seen from the
lateral (A) and medial (B) aspects

27. Movements
• The mandible can be depressed or elevated,
protruded or retracted. Rotation can also
occur, as in chewing.
• In the position of rest, the teeth of the
upper and lower jaws are slightly apart. On
closure of the jaws, the teeth come into
contact.

28. • Depression of the Mandible
• As the mouth is opened, the head of the mandible
rotates on the undersurface of the articular disc
around a horizontal axis.
• Depression of the mandible is brought about by
contraction of the digastrics, the geniohyoids, and
the mylohyoids and the lateral pterygoids.
• Elevation of the Mandible
• First, the head of the mandible and the disc move
backward, and then the head rotates on the lower
surface of the disc.
• Elevation of the mandible is brought about by
contraction of the temporalis, the masseter, and the
medial pterygoids.
• The head of the mandible is pulled backward by the
posterior fibers of the temporalis.

30. • Protrusion of the Mandible
• The articular disc is pulled forward onto the
anterior tubercle, carrying the head of the
mandible with it.
• All movement thus takes place in the upper
cavity of the joint.
• In protrusion, the lower teeth are drawn
forward over the upper teeth, which is
brought about by contraction of the lateral
pterygoid muscles of both sides, assisted by
both medial pterygoids.

31. • Retraction of the Mandible
• The articular disc and the head of the mandible
are pulled backward into the mandibular fossa.
Retraction is brought about by contraction of the
posterior fibers of the temporalis.
• Lateral Chewing Movements
• These are accomplished by alternately protruding
and retracting the mandible on each side.
• For this to take place, a certain amount of rotation
occurs, and the muscles responsible on both sides
work alternately and not in harmony.

32. • Important Relations of the Temporomandibular
Joint
• Anteriorly: The mandibular notch and the
masseteric nerve and artery.
• Posteriorly: The tympanic plate of the external
auditory meatus and the glenoid process of the
parotid gland
• Laterally: The parotid gland, fascia, and skin
• Medially: The maxillary artery and vein and the
auriculotemporal nerve