The Skull and Temporomandibular Joint

Question 1

What are the two major components of the skull?

Answer 1

The neurocranium and the viscerocranium

Question 2

What are the fibrous joints of the skull called?

Answer 2

Sutures.

Question 3

What is the calvaria?

Answer 3

The upper box-like construct of the neurocranium that houses the brain.

Question 4

What is the name of the skull base and what is its function?

Answer 4

• The chondrocranium.

- It articulates the skull with the vertebral column.

Question 5

What is the neurocranium?

Answer 5

The protective vault surrounding the brain and brain stem.

Question 6

What is the viscerocranium?

Answer 6

The skeleton that supports facial structure.

Question 7

How many bones do the neurocranium and viscerocranium include?

Answer 7

22:

• 8 bones of the neurocranium.
• 14 bones of the viscerocranium.

Question 8

List the bones of the neurocranium.

Answer 8

• 1 occipital bone.
• 2 temporal bones.
• 2 parietal bones.
• The sphenoid bone.
• The ethmoid bone.
• The frontal bone.

Question 9

List the bones of the viscerocranium.

Answer 9

• The vomer bone.
• 2 inferior nasal conchae.
• 2 nasal bones.
• 2 maxilla.
• The mandible.
• 2 palatine bones.
• 2 zygomatic bones.
• 2 lacrimal bones.

Question 10

How are the bones of the skull classified?

Answer 10

They are flat bones.

Question 11

List the bony lamina of the skull.

Answer 11

• 2 plates of compact bone.

- 1 middle layer of diploe (spongy cancellous bone).

Question 12

List the suture lines of the skull.

Answer 12

1 - Coronal.

2 - Sagittal.

3 - Lambdoid.

4 - Bregma (point at anterior end of sagittal).

5 - Lambda (point at posterior end of sagittal).

Question 13

List the fossae of the cranial floor.

Answer 13

• Anterior fossa.
• Middle fossa.
• Posterior fossa.

Question 14

List the bones that comprise the cranial floor.

Answer 14

1 - The ethmoid bone.

2 - The sphenoid bone.

3 - The occipital bone.

4 - The paired frontal bones.

5 - The paired temporal bones.

Question 15

What is the mental symphysis?

Answer 15

The fibrous joint that joins the left and right mandibles.

Question 16

Which two bones articulate to form the temporomandibular joint?

Answer 16

The mandible and temporal bone.

Question 17

List the articular sites of the temporomandibular joint and describe their shape.

Answer 17

• The mandibular fossa of the temporal bone (posterior and concave).
• The articular tubercle / eminentia articularis of the mandible (anterior and convex).

Question 18

What type of joint is the temporomandibular joint?

Answer 18

A modified hinge synovial joint.

Question 19

What structure separates the mandible from the temporal bone in the joint capsule of the temporomandibular joint, compartmentalising the synovial cavity?

Answer 19

A fibrous disc known as the articular disc / meniscus.

Question 20

How many compartments does the synovial cavity of the temporomandibular joint have?

Answer 20

2; an upper and lower cavity.

Question 21

What movements do the cavities of the temporomandibular joint allow?

What type of joints do the cavities assume the role of?

Answer 21

• Translational movements in the upper cavity (acts as a gliding joint).
• Rotational movements in the lower cavity (acts as a hinge joint).

Question 22

Other than compartmentalising the cavity, what is the function of the articular disc / meniscus that separates the mandible from the temporal bone in the temporomandibular joint?

Answer 22

It improves the fit of the articular surfaces of the temporal bone and mandible.