Ostelogy Of Skull

Question 1

What kind of ossification do flat bones from from

Answer 1

Intramembranous ossification ( no cartilage precursor)

• mesenchymal cells differentiate directly into odontoblasts which then becomes bone there is no cartilage precursor involved.

Question 2

Irregular bones form from which kind of ossification ?

Answer 2

Endochondral ossification

• mesenchymal cells differentiate into chondroblasts which lay down hyaline cartilage which is then replaced by bone.

Question 3

Define Pneumatised bones and why do they exist?

Answer 3

These are bones which air spaces ( air cells or sinuses). We have these to reduce the weight of our skull and provide resonances our voice.

Question 4

How many bones are present in the skull excluding the ossicles of the ear

Answer 4

22

Question 5

What two processes form the zygomatic arch?

Answer 5

Temporal process of zygomatic bone and the zygomatic process of the temporal bone

Question 6

Name the superior and posterior borders of the temporal fossa

Answer 6

Superior and inferior temporal lines

Question 7

Anterior border of the temporal fossa

Answer 7

Frontal process of zygomatic bone and zygomatic process of frontal Bone

Question 8

Inferior border of temporal bone

Answer 8

Infra-temporal crest deep. To. Zygomatic arch

Question 9

What is the Nasion?

Answer 9

Where the frontal nasal and internal sutures meet

Question 10

Where would you find the glabella

Answer 10

Smooth part of the frontal bone between the eyebrows

Question 11

Name the star shaped junction where 3 sutures between the occipital, parietal and temporal bones meet

Answer 11

Asterion

Question 12

The name of the junction between the lamboid and saggitall sutures

Answer 12

Lambda

Question 13

The junction of the coronal and saggital sutures is

Answer 13

Bregma

Question 14

The inion is what

Answer 14

The most prominent part of the occipital tuberance

Question 15

What is the Pterion

Answer 15

Represents the junction of the 4 skull bones ( greater wing of the sphenoid, frontal, parietal and sphenoid)

Question 16

What is the significance of trauma to the pterion

Answer 16

Structurally weak and it overlies the anterior branch of the middle meningeal artery, so trauma can lead to a epidural haematoma

Question 17

What is a sutural bone and where are they most common

Answer 17

It is a small island of bone within a coronal suture ( usually in lamboid) - highlights the way the skull grows and expands allowing for development/ birthing

Question 18

Where does the nuchal ligament attach

Answer 18

The inferior nuchal line ( part of occipital bone)

Question 19

What is a suture in the skull and why would it ever move

Answer 19

It is a type of fibrous joint, that is a synarthrosis. However it will allow for minimal movement for biomedical protection so to Absorb force

Question 20

What is a synarthosis

Answer 20

Joint where no movement occurs

Question 21

Fontaelles?

Answer 21

Flat bones are separated by fibrous membranes that fuse in post natal life. ( will have until about 18mnths-2 years).
Posterior - close in first year
Initially to allow for moving of cranial shape to facilitate birth and then to allow post natal growth

Question 22

What passes the jugular foramen

Answer 22

The internal jugular vein as well as CN9,10,11

Question 23

What is special about foramen lacerum?

Answer 23

This is an artefact of dry bone because in life it is closed by cartilage because internal carotid artery and carotid plexus pass it .

Question 24

What does the ligamentum nuchae do

Answer 24

Attaches external occipital protuberance and foramen magnum to spinous process of cervical vertebrae

Supports head and resists flexion

Question 25

What is the suprasinous ligament.

Answer 25

Strong fibrous cord which connects C7 to L3/4

Question 26

What are the typical cervical vertebrae

Answer 26

C3-C6

Question 27

What is the function of the Foramen Transversarium

Answer 27

Cervical vertebrae are the only ones with this feature, this is where the vertebral artery passes.

Not usually in C7 as is too small

Question 28

How does C7 attach to ligamenutm nuchae

Answer 28

Non bifed spinous process

Question 29

What is feature of the spinous process in C2-C6 allows for greater area for muscle attachment

Answer 29

They are bifend

Question 30

Function of dens in axis

Answer 30

Tooth like structure which aids in a pivot point for the atlantooccipital joint and atlas

Question 31

What is the atlantooccipital joint

Answer 31

Articulation between atlas and occipital bone, it is a pivot joint allowing for flexion and extension.

Question 32

What is the joint called between atlas and axis and what does it do

Answer 32

atlanto-axial joint and it is a condyloid joint, it allows for the rotation of the head ( shaking your head to say no etc) .

Question 33

What do the lateral atlanto-axial joint and pivot point of dens allow for, which ligament assists this

Answer 33

Allows rotation of head ( side to side)

Assisted by the transverse ligament of atlas holding dens in position

Question 34

What is the function of the alar ligaments

Answer 34

Prevent excessive rotation of head and neck by connecting dens to occipital condoyles

Question 35

Where is the hyoid bone found

Answer 35

At the level of C3 in the neck

Does not articulate with any skeletal elements in the head and neck

Question 36

What does the hyoid bone do and what does it connect

Answer 36

Helps keep the airway open

Connects with oral cavity with pharnyx posterioly and larynx inferiorly

Question 37

What is the function of the parietal foreman

Answer 37

Allows for passage of emissary veins connecting superficial veins to deeper veins

Question 38

What is the function of the vertical foramen

Answer 38

Allows for the spinal cord to pass