Anatomy as well oral surgery topic

1. MUSCLES OF
MASTICATION
• Dr.Faisal K A
• Tutor
• Malabar Dental College and Research Centre

2. • Mastication or chewing is the first mechanical process in
the gastrointestinal tract by which the food substances
are cut into small particles and crushed or ground into a
soft bolus by using teeth
• Muscles of mastication are paired in each side and work
together to produce the movement of mandible.
• Masticatory muscles are developed from mesoderm of
first branchial arch.
• They move during mastication and speech.

3. 4 MAIN MUSCLES
Muscles attached to rami of
mandible
• Temporalis
• Medial pterygoid
• Lateral pterygoid
• Masseter

4. • Quadrilateral shaped
• 3 layers
1. Superficial
2. Deep
3. Intermediate

5. • Origin
• Superficial layer: lower border of
anterior two-third of zygomatic arch and
adjoining zygomatic process of maxilla.
• Middle layer :from anterior
twothirds of deep surface and posterior
one third of lower border of zygomatic
arch.
oDEEP LAYER; From deep surface
of zygomatic arch
• Insertion:
• Ramus of mandible

7. • Relations:
• Superficial: skin,platysma,parotid gland,
branches of facial nerve and transverse
facial branches of superficial temporal
vessels
• Deep: ramus of mandible, temporalis muscle
• Anterior :buccal pad of fat,buccal branch of
mandibular nerve,buccinator muscle
• Posterior: it is overlapped by parotid gland
• Actions:
• Elevation of mandible to approximate the
teeth
• Retraction of mandible
• Superficial fibres help in protrusion of
mandible
• Nerve Supply:
Masseteric nerve ,branch of anterior division of

8. Fan shaped
Fills the temporal
fossa

9. Origin :a)temporal fossa
excluding zygomatic bone
b)Temporal fascia

11. • Insertion :
 margin& deep surface
of coronoid proces
Anterior border of
ramus of mandible

12. • Relations:
• Superficial: skin ,temporal fascia,superfacial
temporal vessels,auriculotemporal nerve,
temporal branches of facial nerve,zygomatic
arch and masseter muscle
• Posterior :contents of infratemporal fossa in
lower part
• Anterior :the tendon is separated from
zygomatic bone by pad of fat
• Actions:
 elevate mandible to occlude teeth
 retract mandible after protrusion
• Nerve Supply:
Temporal branches from anterior division of
mandibular nerve

13. • Thick quadrilateral muscle
• Small superficial head
• Large deep head

14. • Origin:
From two heads:
 Superficial head: maxillary tuberosity on infra
temporal surface of maxilla,adjoining surface of
pyramidal process of palatine bone
Deep head: medial surface of lateral pterygoid plate of
sphenoid bone

15. • Insertion :
 medial surface of ramus of mandible
posteroinferior to mylohyoid groove
 inner aspect of angle of mandible

16. • Relations:
 Lateral: lateral pterygoid
muscle,sphenomandibular ligament, maxillary
artery, inferior alveolar nerve and vessels,
lingual nerve, part of parotid gland
 Medial: tensor veli palatini, styloglossus,
stylopharyngeus and superior constrictor
muscles
• Actions:
 assist in elevation of mandible
 along with lateral pterygoid muscle it causes
protrusion of mandible
Help in side to side movements of jaw and
grinding of food between teeth of same side
• Nerve Supply
nerve to medial pterygoid, branch of the
main trunk of mandibular nerve

17. • Key muscle of infratemporal fossa
• Short ,conical and have upper and lower heads

18. • Origin:
→Upper head: lower part of infra temporal surface
of the great wing of sphenoid and adjoining
infratemporal crest
→Lower head: larger and arises from lateral
surface of lateral pterygoid plate of sphenoid
bone

19. Relations:
→Superficial: ramus of
mandible,masseter,superficial head of medial
pterygoid and tendon of temporalis muscles
→Deep :deep head of medial pterygoid
muscle,sphenomandibular ligament,maxillary
and middle meningeal arteries,mandibular
nerve
→Superior :temporal and massetric branches
of mandibular nerve
→Inferior :lingual and inferior alveolar nerves
→Structures present between two heads:
buccal nerve and maxillary artery

20. • Insertion:
both heads converge to form
single tendon to insert on:
→ Pterygoid fovea in the
anterior surface of neck of
mandible
→Adjoining articular disc and
capsule of TMJ
• Actions:
Assists in depression of
mandible to jaw
Protrusion of mandible
along with medial pterygoid
Helps in side to side
movements of the jaw and
grinding of food between
teeth of same side
• Nerve Supply:
Branches from anterior
division of mandibular nerve

21. • Maxillary artery – larger terminal branch of external
carotid artery
• Divided into three parts by lateral pterygoid muscle
• Second part (pterygoid part) supplies muscles of
mastication

23. • Trismus-prolonged tetanic spasm of jaw muscles by
which normal opening of mouth is resticted(locked jaw)
• Myofascial pain
• A lesion at the foramen ovale leads to paralysis of
muscles of mastication leads to loss of jaw – jerk reflex

24. • Anand’s textbook of Human Anatomy
• Textbook of Anatomy BD Chaurasia
• Internet :www.wikipedia.com

25. •Thank you