The Infratemporal and Temporal Fossa 1

Question 1

What is the mandible?

Answer 1

The lower jaw.

Question 2

What does the mandible have 2 of?

Answer 2

It has 2 mandibular condyles.

Question 3

What do the 2 mandibular condyles articulate with?

Answer 3

They articulate with the left and right temporal bones at the temporomandibular joints.

Question 4

Where does the body of the mandible lie?

Answer 4

It lies on either side of the mouth.

Question 5

Where are the 2 halves of the body of the mandible continuous?

Answer 5

They are continuous in the midline anteriorly at the mandibular symphysis.

Question 6

Where is the ascending ramus of the mandible?

Answer 6

This runs between the posterior aspect of the body of the mandible and the mandibular condyle below.

Question 7

What is the angle of the mandible?

Answer 7

This is the point on the lower body of the mandible where the body and the ascending ramus are continuous.

Question 8

Anteriorly, what is the ascending ramus of the mandible surmounted by?

Answer 8

It is surmounted by a coronoid process.

Question 9

Where is the mandibular notch?

Answer 9

This is between the coronoid process and the condyle in the upper border of the ascending ramus.

Question 10

Where do structures within the temporal and infratemporal fossa lie?

Answer 10

They lie between the pharynx and the side of the face.

Question 11

Where does the infratemporal fossa lie?

Answer 11

It lies between the pharynx and the ascending ramus of the mandible.

Question 12

What is the roof of the infratemporal fossa?

Answer 12

The base of the skull.

Much of the roof is formed by the undersurface of the greater wing of the sphenoid bone.

Question 13

What bone do the foramen ovale and the foramen spinosum pass through?

Answer 13

They pass through the sphenoid bone in the base of the skull.

Question 14

Where is the stylomastoid foramen in the base of the skull?

Answer 14

It is positioned just deep to the mastoid process and lateral to the styloid process.

Question 15

What parts of the temporal bone lie towards the back of the roof of the infratemporal fossa?

Answer 15

They styloid process of the temporal bone and the tympanic plate of the temporal bone.

Question 16

What part of the sphenoid bone lies near the front of the infratemporal fossa?

Answer 16

The pterygoid plates of the sphenoid bone.

Question 17

How many large muscles are attached to the ascending ramus and the condyle of the mandible?

Answer 17

4 muscles.

Question 18

What do the muscles of mastication do?

Answer 18

They move the mandible during chewing, speaking and swallowing.

Question 19

What part of the mandible do these 4 muscles attach to?

Answer 19

2 of the muscles attach to the outside of the mandible and 2 of the muscles attach to the inside of the mandible.

Question 20

What are the 2 muscles of mastication that are on the inside of the mandible called?

Answer 20

These are called the medial and lateral pterygoid muscles.

Question 21

What are the 2 muscles of the mastication that are attached to the outside of the mandible called?

Answer 21

They are called the masseter and temporalis muscle.

Question 22

Where does the lateral pterygoid muscle arise from?

Answer 22

It arises from the undersurface of the greater wing of the sphenoid bone and from the lateral aspect of the lateral pterygoid plate of the sphenoid bone.

Question 23

What can we say about the undersurface of the greater wing of the sphenoid bone and the lateral aspect of the lateral pterygoid plate of the sphenoid bone?

Answer 23

These 2 surfaces are continuous and next to each other – they are the roof of the infratemporal fossa that faces downwards and the medial wall of the infratemporal fossa that faces laterally.

Question 24

What does the lateral pterygoid muscle arise as?

Answer 24

Arises as 2 heads – an upper and lower head, one from each of the surfaces of the sphenoid bone.

Question 25

What happens between the 2 heads of the lateral pterygoid muscle?

Answer 25

Structures can squeeze in and out of the infratemporal fossa between these 2 heads.

Question 26

What is the insertion of the lateral pterygoid muscle?

Answer 26

It inserts into the neck of the mandible just below the condyle into a depression here called the fovea.

Question 27

What is the path of the lateral pterygoid muscle for its origin so that it can run to its insertion?

Answer 27

It runs backwards and laterally from the origin.

Question 28

Where does a part of the upper head of the lateral pterygoid muscle insert?

Answer 28

It inserts into the disc or meniscus of the temporomandibular joint

Question 29

When is the lateral pterygoid muscle active?

Answer 29

When we protrude our chin or open our mouths.

Question 30

When else is the upper head of the pterygoid muscle also active?

Answer 30

It is also active when we are closing our mouths because it steadies the meniscus and the condylar head against the posterior slope of the articular eminence as they slide back into the glenoid fossa.

Question 31

Where does the medial pterygoid muscle arise from?

Answer 31

It arises from the medial aspect of the lateral pterygoid plate.

Question 32

Where does the medial pterygoid muscle insert?

Answer 32

It inserts into the inner aspect of the angle of the mandible.

Question 33

How does the medial pterygoid muscle reach the lower margin of the ascending ramus?

Answer 33

It runs downwards and laterally to reach the lower margin of the ascending ramus.

Question 34

When is the medial pterygoid muscle active?

Answer 34

It is active during close of the jaws or when occluding the teeth together.

Question 35

Where does the masseter muscle take origin from?

Answer 35

Takes origin from the zygomatic arch and runs downwards.

Question 36

How many parts does the masseter muscle have?

Answer 36

2 parts – a deeper part and a superficial part.

Question 37

Where does the deeper part of the masseter muscle take origin from?

Answer 37

It takes origin from the inner surface of the zygomatic arch and runs vertically down the outer aspect of the ramus.

Question 38

Where does the superficial part of the masseter muscle take origin from?

Answer 38

It takes origin further anteriorly from the undersurface of the zygomatic arch.

Runs downwards and backwards to the outer surface of the ascending ramus of the mandible.

Question 39

What is the function of the masseter muscle?

Answer 39

It closes the mandible and occludes the teeth together.

Question 40

Where does the temporalis muscle arise from?

Answer 40

It arises from the side of the vault of the skin and from a tough fascia that covers the surface of the muscle called the temporalis fascia.

Question 41

Where the temporalis muscle takes origin from, what are the sides of the vault bones marked with?

Answer 41

They are marked with temporal lines where the muscle takes origin from.

Question 42

What fossa does the temporalis muscle pass through?

Answer 42

It passes through the temporalis fossa.

Question 43

What is the temporalis fossa bounded laterally by?

Answer 43

It is bounded laterally by the zygomatic arch.

Question 44

Where is the insertion of the temporalis muscle?

Answer 44

It inserts on to the coronoid process of the mandible and the inner aspect of the anterior border of the ascending ramus.

Question 45

What is the function of the temporalis muscle?

Answer 45

It occludes the teeth and is active during jaw closure.

Question 46

Give a general idea of the process of chewing.

Answer 46

Chewing is a complicated process and many of the muscles of mastication are active during different points of the chewing cycle.

Question 47

What does chewing involve?

Answer 47

Chewing involves an alternating pattern of lateral mandibular movements which shift the mandible for left to right as well as simply grinding the teeth on one side together.

Question 48

What muscles play an important role in the lateral movement of the mandible at the same time?

Answer 48

The masseter muscle and the pterygoid because they bring about movements of jaw closing and opening.

Question 49

What movements of the mandible does speech involve?

Answer 49

Speech only involves up and down movements of the mandible.

Question 50

What happens when we are swallowing solids?

Answer 50

There is firm bilateral occlusion of the jaws while the tongue forces food backwards and into the oropharynx.