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Muscles of mastication – Origin, Insertion, Function, Nerve and Blood supply

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The muscles which are required for mastication or chewing are known as the muscles of mastication. These muscles help mainly in the movement of the mandible and not the maxilla as maxilla is an integral part of the skull and the mandible being the only movable bone in the skull. The muscles help in moving the mandible at the Temporomandibular Joint which helps in chewing or food, talking, yawning, etc.

There are many muscles which help in the process of mastication but the main muscles which take part in the process are

Primary Muscles Of Mastication:

  • Masseter muscle
  • Temporalis
  • Lateral Pterygoid
  • Medial Pterygoid

Accessory Muscles Of Mastication: 

The secondary muscles or Accessory muscles are divided further into two types based on their position.

Buccinator

Suprahyoid Muscles  

  •  Digastric
  •  Stylohyoid
  •  Mylohyoid
  •  Geniohyoid

Infrahyoid muscles

  • Sternohyoid
  • Thyrohyoid
  • Omohyoid

Now let us discuss in detail about each of these muscles:

Masseter Muscle:

It is one of the main muscle which helps in the process of mastication

In humans, the masseter is the second most efficient masticatory muscle. Its origin and insertion make it very useful for the movement of the jaw and for applying good bite force for mastication.

Masseter muscle is a powerful muscle because of its Multipennate arrangement of fibers

The masseter muscle extends from the zygomatic arch to the ramus and body of the mandible. The fibers of this muscle are broad, extending from the region of the second molar on the surface of the mandible to the surface of the ramus. The muscle is divided into 2 parts

  • Superficial
  • Deep

Origin of masseter muscle:

  • Superficial layer – anterior 2/3rd of lower border of zygomatic arch & zygomatic processof maxilla
  • Middle layer – anterior 2/3rd of deep surface & posterior 1/3rd of lower border of zygomatic arch
  • Deep layer – deep surface of zygomatic arch

Insertion of masseter muscle:

  •  Superficial layer –lower part of lateral surface of ramus of mandible
  •  Middle layer –middle part of ramus
  •  Deep layer – upper part of the ramus & coronoid process

The main function of masseter muscle is

  • Elevation of the mandible
  • lateral movements of the mandible for efficient chewing and grinding of the food
  • unilateral chewing
  • Retraction of the mandible

Blood supply of masseter muscle:

  • Masseteric artery .

Nerve supply of masseter muscle:

  • Massetric nerve.

Clinical Importance of Masseter Muscle of Mastication:

  • Masseter muscle can be palpated both intraorally and extra orally
  • Most common muscle involved in Myositis Ossificans
  • Masseter Muscle shows Dual action in Complete Denture
  • The muscle that commonly undergoes Hypertrophy in Bruxism is Masseter
  • Because of the Multipennate arrangement of fibers masseter is a very powerful muscle

Masseter Muscle Function – Elevation of Mandible

Temporalis Muscle:

This is the muscle which helps in elevation of the mandible, It is one of the muscles of mastication. It is large shaped in appearance and covers the Temporal area of the skull.

Origin and Insertion of Temporalis Muscle:

  • From the Parietal bone of the skull and is inserted on the coronoid process of the mandible.

Arterial supply of Temporalis Muscle:

  • The Deep Temporal artery supplies the large muscle.

Nerve Supply of Temporalis Muscle:

  • Trigeminal nerve( this nerve has been associated with being the cause of Headache and migraine.

Functions of Temporalis Muscle:

  • Elevation of the mandible
  • Retraction of the mandible.
  • Crushing of food between the molars.
  • Posterior fibers draw the mandible backwards after it has been protruded.
  • It is also a contributor to side to side grinding movement.

Clinical Importance of Temporalis Muscle:

  • Sudden contraction of temporalis muscle will result in coronoid fracture, which is rare.

Temporalis muscle

 

Lateral Pterygoid Muscle:

This is a small muscle which also helps in the mastication process. It is divided into 2 heads

Origin of Lateral Pterygoid Muscle:

  • Upper head – infratemporal surface & crest of greater wing of sphenoid bone
  • Lower head – lateral pterygoid plate

Insertion of Lateral Pterygoid Muscle:

  • Pterygoid fovea on the anterior surface of neck of mandible
  • Anterior margin of articular disc & capsule of TMJ

Nerve Supply of Lateral Pterygoid Muscle:

  • Pterygoid branch of Trigeminal nerve.

Arterial supply of Lateral Pterygoid Muscle:

  • Pterygoid branch of Maxillary artery.

Functions of Lateral Pterygoid Muscle:

  • Depresses the mandible
  • Protrudes it forward for opening of the jaw
  • Side Movements

Clinical Importance of Lateral Pterygoid Muscle:

  • Most commonly involved muscle in MPDS
  • Only muscle of mastication which has its attachment to the TMJ
  • Lateral Pterygoid forms the roof of the Pterygomandibular space.

 

The combined efforts of the Digastric and Lateral Pterygoid provide for natural jaw opening.

 

Medial Pterygoid muscle:

It is a thick muscle of mastication.

Origin and Insertion of Medial Pterygoid Muscle:

  • It Arises from the deep head the lateral pterygoid plate, and from the maxillary tuberosity.
  • Insertion is seen on the Medial angle of the Mandible.

Arterial supplyof Medial Pterygoid Muscle:

  • Pterygoid branch of Maxillary artery.

Nerve Supply of Medial Pterygoid Muscle:

  • Mandibular nerve through the medial pterygoid.

Functions of Medial Pterygoid Muscle:

  • Elevates the mandible,
  • Closes the jaw,
  • Helps in side to side movement.

Lateral Pterygoid and medial pterygoid muscle.

Clinical Importance of Medial Pterygoid Muscle:

  • Medial Pterygoid muscle can be palpated only intraorally
  • Most commonly involved in MPDS
  • Trismus following inferior alveolar nerve block is mostly due to involvement of medial pterygoid muscle

Unique features of Masticatory Muscles:

  • Have shorter contraction times than most other body muscles
  • Incorporate more of muscle spindles to monitor their activity
  • Do not have golgi tendon organs to monitor tension
  • Elevators predominantly white fibrous which perform fast twitching
  • Do not get fatigued easily
  • Psychological stress increases the activity of jaw closing muscles
  • Occlusal interferences cause a hypertonic synchronous muscle activity
  • Closing movement also determined by the height of the teeth

 

Comments

  1. Hi varun,Good Blog,I think first of its kind;But generally blogs are about information uique to you or your organisation.You are giving textbooks.I am in practice since about 18 years so please take it as a well wisher opining.Try to say something unique …customises….
    DrAshish
    Blog:www.drashish.com

  2. Thanks for ur sound advice Dr.ashish,
    I made this site only concentrating on students and, here am trying to simplify the important topics in the subjects mostly the I and II yr BDS, as myself am a student doing my III yr, so i want to make it a place where a student can get the information easily.
    i will surely try to make it more unique and write different stuff regarding student life.
    Thanks for your advice, i have really taken it on a positive note.

  3. thanks for this helpfull site it need alittle bit more videos for all topics…. but generally u doing so will guys

  5. Thank you very much to you who designed this site it is a grate help for student.

  8. hi Mandy,
    I am really happy that this is helping you in your exams i wrote this particular topic in a way which my proffesor told of would impress the examiner and fetch me the maximum marks if presented the same way with required diagrams. All the best for your exams.
    Cheers varun.

  9. God job Varun, i am student of final year and believe in wot u believe. i have a community “Chandigarh Dental students” on orkut where i am doing same.
    i will ask my friends to take help from this blog, and one suggestion- do get an adsense account after which you can earn too out of your blog.

    Aman
    Chandigarh

  10. hey everyone, tnx for the info.. by the way, always watch every L.A. Clippers game in NBA.. because of these informations, i can now classify all my muscles and i can now use these informations in our project

  14. your website is useful and good for student and information is so simple and easy to understand

  16. Among only the muscles of mastication the Masseter is the strongest one, but coming to the strongest muscles in the face the Tongue is the strongest muscles.

  17. It’s funny that you so called “Doctor’s” can not spell anything correctly.

    As for the site, I agree it is very beneficial.

  18. @Emily: Where did you find the mistakes can you please tell me so that i can correct them!!!
    Sorry for the inconvenience.

  19. I think Emily was talking about some of the comments. There were a few spelling and grammar mistakes form some of the Doctors.

  20. hi varun..that was really helpful…but i want somerelated articles for recent advances in applied.

  21. Hey varun I just want it to say thank you so much.I’ve learned a lot form this. keep up the good work.

  25. Your webiste is really great and i am sure hard work has been put into creating it.
    Great job and keep up the good job of providing such educational information…

    Oral health student… :)

  26. definately agree with you Cathy, i have turned to this website for my exam revision too and its just so nice and simple to understand.

  28. The buccinator muscle has two functions related to eating (in addition to its importance to musicians). During chewing, it cooperates with the masticatory muscles by moving food back across the teeth from the space inside the cheeks.

    Its purpose is to pull back the angle of the mouth and to flatten the cheek area, which aids in holding the cheek to the teeth during chewing. So that food does not slip in the vestibular area.

  31. good information, precise n easy to remember but yeah quite a lot of spellings need correction.
    no offence Dr. Varun, your efforts are much appreciated

  32. thanks for this simple yet imformative site. i found answers to all my questions.
    keep it up

  33. @Varun sir.
    m a 1st yr.BDS student. n this blog’f urs is Quite helpul as it gives us d format in wch 2 write answers 2 gain maximum marks .
    thanx a lot..

  38. Hi I’m a first year student in Australia and found this helpful, however you state that the masseter retracts the mandible. Shouldn’t it say protrude? I believe retrusion is via the posterior fibres of the temporalis or am I wrong?

  42. This blog is really wonderful for it will help students doing research work and improve their knowledge

  45. hey varun… thnx alot for this information. this is a very clear and precised discription about the topic.

  48. hi,tnx for useful information, I need some more information about clinical examination of mastication muscles , I afraid if u could help me.

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