The document summarizes the muscles of mastication, which are the muscles responsible for chewing food. There are four main muscles - the masseter, temporalis, lateral pterygoid, and medial pterygoid muscles. These muscles all originate on bones of the skull and insert onto the mandible or jawbone. Working together, they elevate, depress, protrude, and move the mandible from side to side during chewing. Damage to these muscles or their nerve supply can result in conditions like trismus where the jaw is locked shut.

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