Muscles of Mastication Lecture SMSPP 2010 v1.1

8/7/2019 Muscles of Mastication Lecture SMSPP 2010 v1.1

1/15

Muscles of Mastication

ColbyVictoria


2/15

What are the muscles?

Masseter

Temporalis

Medial Pterygoid Lateral Pterygoid


3/15

Masseter

Overlies lateral surface oframus of mandible

Quadrangular shaped

Anchored above to zygomatic

bone & anterior 2/3 of maxilla Superficial origin: Maxillaryprocess of zygomatic bone

Deep origin: medial aspect ofzygomatic arch

Innervated by Masseteric nerve

(from V3) Vascularized by Masseteric

artery (from Maxillary A)

Figure 8.132: Masseter muscle


4/15

Figure 8.135: Nerves and arteries of the temporal fossa

Temporalis

Fan shaped, fills temporal fossa

Origin: from bony surface oftemporal fossa to inferiortemporal line

Anterior fibers vertically

oriented Posterior fibers horizontally

oriented

Fibers form TENDON

Inserts: coronoid process ofmandible

Innervation: Deep temporalnerves (from V3)

Vascularization: Deep temporalarteries (from middle temporal A)

Figure 8.134: Temporalis muscle. Lateral View


5/15

Medial Pterygoid

Quadrangular shaped with 2heads:

Deep head: Origin: Medial surface of lateral

plate of pterygoid process &

pyramidal process of palatinebone

Superficial head: Origin: tuberosity and pyramidal

process of maxilla

Insert the same place: Medialsurface of mandible (near the

angle) Innervation: Nerve to medial

pterygoid (from V3)

Vascularization:Figure 8.137: Medial pterygoid muscle


6/15

Lateral Pterygoid

Thick triangular muscle with 2heads

Upper head: Origin: roof of infratemporalfossa

(lateral to foramen ovale and

spinosum) Lower head: larger

Origin: lateral plate of thepterygoid process (tracksbetween the 2 heads of medialpterygoid)

Insertion: pterygoid fovea of neck

of mandible AND into capsule ofTMJ

Innervation: nerve to lateralpterygoid (from V3)

Vascularization:

Figure 8.138: Lateral pterygoid muscle


7/15

Consequences of Mal-Occlusion

Abfraction:Wedgeshaped loss of toothstructure at cervical due to heavyabnormal occlusalforce.

Tension

ripped apart

Attrition corresponding to

Occlusalforces.Loss of structure due to tooth-tooth contact

Deciduous and permanent dentition

Wear facets correspond to occlusal pattern

Increased likelihood poor quality of

enamel, edge to edge occlusion, prematureocclusion, intraoral abrsives, grinding ofteeth

Shortening of arch length

Pulp exposure and sensitivity are rare

Early diagnosis and intervention

Chronic malocclusion


8/15

2ndmost common source of facialpain

Women are 4 times more likely to

have TMJ disorder

Most common in people 20-40

years old

20-25% of the population have

symptoms of a TMJ disorder

Only 3-4% of the population

seek treatment

About 70% of reported TMJ

disorder cases are attributed topathologies involving the disc

TMJ disorder


9/15

Summary Slide


10/15

9


11/15

25


12/15

2

.


13/15

4


14/15

20


15/15

24

Muscles of Mastication Lecture SMSPP 2010 v1.1

Documents

Transcript of Muscles of Mastication Lecture SMSPP 2010 v1.1