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MD1 Neuroscience > Skull > Flashcards

Flashcards in Skull Deck (67)
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1
Q

Is the skull made of one bone?

A

No, separate bones

2
Q

What is the skull divided into?

A

Cranium

Face

3
Q

From what are the facial bones suspended?

A

Front of cranial bones

4
Q

What does the facial skeleton form?

A

Orbits
Nasal cavity
Lower jaw

5
Q

What are the two parts of the cranium?

A
Upper = vault
Lower = floor/base of skull
6
Q

What does the vault contain?

A

Brain
Meninges
Cranial nerves and vessels

7
Q

Describe the bone composition of the vault

A

External and internal table of compact bone

In between is layer of spongy bone = diploe

8
Q

How are separate bones united in the skull?

A

United at series of immobile joints called sutures

9
Q

What is the coronal suture?

A

In the coronal plane

Frontal bone anteriorly unites with parietal bones behind

10
Q

What is the sagittal suture?

A

In the sagittal plane

Right and left parietal bones unite

11
Q

What is the lambdoid suture?

A

In the coronal plane

Parietal bones unite with occipital bone

12
Q

What is the pterion?

A

H shaped suture where four cranial bones meet

Bones particularly thin here

13
Q

What are the four cranial bones that unite at the pterion?

A

Frontal
Parietal
Sphenoid
Temporal

14
Q

What is directly deep to the pterion?

A

Middle meningeal artery

Grooves internal aspect of pterion

15
Q

What does the middle meningeal artery supply?

A

Meninges and cranial bones

16
Q

What are the two parts of the frontal bone?

A

Vertical part forms forehead

Horizontal/orbital plate forms roof of orbit

17
Q

At what point does the front bone turn 90 degrees?

A

At supraorbital margin

18
Q

Describe the parietal bones

A

Flat
Relatively rectangular
Molded to brain contour

19
Q

Describe the occipital bone

A

Flat

Molded to shape of brain posteriorly

20
Q

What is the midline project of the occipital bone called?

A

External occipital protuberance

21
Q

Describe the squamous part of the temporal bone

A

Flat

Molded to lateral aspect of brain

22
Q

What are the four processes of the temporal bone?

A

Zygomatic
Styloid
Mastoid
Petrous

23
Q

Describe the zygomatic process

A

Extends anteriorly
Articulates with zygoma
Creates zygomatic arch

24
Q

What is the zygoma?

A

Cheek bone

25
Q

Describe the styloid process

A
Sharp spike of bone
Extends inferiorly
Deeply placed
Gives attachment to muscles with stylo in their names - midline structures
- Muscles of tongue
- Muscles of pharynx
26
Q

Describe the mastoid process

A

Extends posteroinferiorly
Thick, chunky, and superficially placed
Gives attachment to sternoclydomastoid muscle and others
Full of mastoid air cells

27
Q

Describe the petrous process

A

Internal
Thick pyramidal shape
Projects inwards to cranial vault
Forms part of cranial floor

28
Q

Describe the sphenoid bone

A
Like bat with outstretched wings
In middle of floor
Made of three parts
- Body
- Lesser wing
- Greater wing
- Two small legs
29
Q

Describe the body of the sphenoid bone

A

Not solid piece of bone

Pituitary gland sits in cavity

30
Q

Describe the wings of the sphenoid bone

A

Flip out and up
Flipped up part form small part of lateral aspect of cranium
Part of pterion

31
Q

What is the slit between the two wings of the sphenoid bone?

A

Superior orbital fissure

32
Q

What does the superior orbital fissure do?

A

Separates wing into small anterosuperior part = lesser wing, and large posteroinferior part = greater wing

33
Q

What are the two legs of the sphenoid bone called?

A

Pterygoid plates

34
Q

Are the pterygoid plates part of the cranial floor?

A

No

35
Q

Generally describe the inferior aspect of the brain

A

Not flat

Step appearance

36
Q

How many pairs of cranial nerves are there?

A

12

37
Q

Where do the cranial nerves emerge from?

A

Inferior aspect of brain

38
Q

Is the cranial floor flat?

A

No, it’s stepped

39
Q

Why are there holes in the cranial floor?

A

To allow exit of cranial nerves

40
Q

How are the fossae of the cranial floor arranged?

A

In stepwise configuration

41
Q

What does the anterior cranial fossa support?

A

Frontal lobes

42
Q

Where does the anterior cranial fossa sit?

A

Above and in front of middle cranial fossa

43
Q

What does the middle cranial fossa support?

A

Temporal lobes

44
Q

Where does the middle cranial fossa sit?

A

Behind and below anterior cranial fossa

45
Q

What does the posterior cranial fossa support?

A

Brain stem

Cerebellum

46
Q

Where does the posterior cranial fossa sit?

A

Behind and below middle cranial fossa

47
Q

Which bones make up the anterior cranial fossa?

A

Horizontal plates of frontal bone
Lesser wing of sphenoid bone forms edge before step down
Very superior aspect of ethmoid bone

48
Q

Where is the ethmoid bone?

A

Between eyes

Just above nose

49
Q

What is the vertical plate of the ethmoid bone called?

A

Cristagalli

50
Q

What are the holes on either side of the cristagalli in the ethmoid bone called?

A

Cribiform plate

51
Q

Which bones make up the middle cranial fossa?

A

Greater wing of sphenoid anteriorly

Petrous part of temporal bone inferiorly = edge

52
Q

Which bone makes up the posterior cranial fossa?

A

Occipital bone

53
Q

What are the foramenae in the anterior cranial fossa?

A

Cribiform plate

54
Q

What are the foramenae in the middle cranial fossa?

A
Hypophysial fossa
Optic canal
Superior orbital fissure
Foramen rotundum
Foramen ovale
Foramen spinosum
55
Q

What are the foramenae in the posterior cranial fossa?

A

Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Foramen magnum

56
Q

What structure goes through the cribiform plate?

A

Olfactory nerve

57
Q

What structure goes through the hypophysial fossa?

A

Pituitary gland

58
Q

What structures go through the optic canal?

A

Optic nerve

Ophthalmic nerve

59
Q

What structures go through the superior orbital fissure?

A

Nerve to extraocular muscles

Branches of trigeminal nerve

60
Q

What structure goes through the foramen rotundum?

A

Maxillary nerve

61
Q

What structure goes through the foramen ovale?

A

Mandibular nerve

62
Q

What structure goes through the foramen spinosum?

A

Middle meningeal artery

63
Q

What structures go through the internal acoustic meatus?

A

Facial nerve

Vestibulocochlear nerve

64
Q

What structures go through the jugular foramen?

A

Cranial nerve IX
Cranial nerve X
Cranial nerve XI
Internal jugular vein

65
Q

What structure goes through the hypoglossal canal?

A

Hypoglossal nerve

66
Q

How are the foramenae of the middle cranial fossa arranged?

A

Crescent on each side of body of sphenoid
Superior orbital fissure forms proximal half of crescent
In second part of crescent
- Round = foramen rotundum
- Oval = foramen ovale
- Little = foramen spinosum

67
Q

How are the foramenae of the posterior middle cranial fossa arranged?

A

Vertical line
Internal auditory meatus in step down to posterior cranial fossa in petrous part of temporal bone
Jugular foramen in gap between petrous part of temporal bone and occipital bone
Hypoglossal canal related to foramen magnum

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