The muscles which are required for mastication 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.
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:
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.
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:
- 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 :
- 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:
- Masseteric artery .
Nerve supply:
- Massetric nerve.
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:
- From the Parietal bone of the skull and is inserted on the coronoid process of the mandible.
Arterial supply:
- The Deep Temporal artery supplies the large muscle.
Nerve Supply:
- Trigeminal nerve( this nerve has been associated with being the cause of Headache and migrane.
Functions:
- 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.
Lateral Pterygoid Muscle:
This is a small muscle which also helps in the mastication process. It is divided into 2 heads
Origin:
- Upper head – infratemporal surface & crest of greater wing of sphenoid bone
- Lower head – lateral pterygoid plate
Insertion :
- Pterygoid fovea on the anterior surface of neck of mandible
- Anterior margin of articular disc & capsule of TMJ
Nerve Supply:
- Pterygoid branch of Trigeminal nerve.
Arterial supply:
- Pterygoid branch of Maxillary artery.
Functions:
- Depresses the mandible
- Protrudes it forward for opening of the jaw
- Side Movements
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 :
- 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 supply:
- Pterygoid branch of Maxillary artery.
Nerve Supply:
- Mandibular nerve through the medial pterygoid.
Functions:
- Elevates the mandible,
- Closes the jaw,
- Helps in side to side movement.
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
Related posts:
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
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.
thanks for this helpfull site it need alittle bit more videos for all topics…. but generally u doing so will guys
hey thnk you very much for the good info!!
Thank you very much to you who designed this site it is a grate help for student.
hi thank you for the website it will help me alot with my studing for my exam
heyy…your website is so useful. its helping me study for my exam. Thanks alot!!:)
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.
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
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
i shud say …itz gud ….
thnx 4 this great &simple information
i am doing my MDS (OMFS) after 10 yrs of clinical practice
good info about muscles of mastication
wish u all the best
keep going
your website is useful and good for student and information is so simple and easy to understand
i need to know what is the strongest one?
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.
It’s funny that you so called “Doctor’s” can not spell anything correctly.
As for the site, I agree it is very beneficial.
@Emily: Where did you find the mistakes can you please tell me so that i can correct them!!!
Sorry for the inconvenience.
I think Emily was talking about some of the comments. There were a few spelling and grammar mistakes form some of the Doctors.
hi varun..that was really helpful…but i want somerelated articles for recent advances in applied.
Hey varun I just want it to say thank you so much.I’ve learned a lot form this. keep up the good work.
Great website! and will be very beneficial for my exam revision. BIG Thanks.
thanks!
great work
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… :)
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.
Hi I have a quick question. which muscle is involved in mastication but is classed as a muscle of facial expression?
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.
thank u so much! this is really, really helpful!
Thank y for your simple and valuable information. \any way it is very good job. keep in touch
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
thanks for this simple yet imformative site. i found answers to all my questions.
keep it up
@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..
well done varun….very helpful