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MD1 Neuroscience > Skull > Flashcards

Flashcards in Skull Deck (67):
1

Is the skull made of one bone?

No, separate bones

2

What is the skull divided into?

Cranium
Face

3

From what are the facial bones suspended?

Front of cranial bones

4

What does the facial skeleton form?

Orbits
Nasal cavity
Lower jaw

5

What are the two parts of the cranium?

Upper = vault
Lower = floor/base of skull

6

What does the vault contain?

Brain
Meninges
Cranial nerves and vessels

7

Describe the bone composition of the vault

External and internal table of compact bone
In between is layer of spongy bone = diploe

8

How are separate bones united in the skull?

United at series of immobile joints called sutures

9

What is the coronal suture?

In the coronal plane
Frontal bone anteriorly unites with parietal bones behind

10

What is the sagittal suture?

In the sagittal plane
Right and left parietal bones unite

11

What is the lambdoid suture?

In the coronal plane
Parietal bones unite with occipital bone

12

What is the pterion?

H shaped suture where four cranial bones meet
Bones particularly thin here

13

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

Frontal
Parietal
Sphenoid
Temporal

14

What is directly deep to the pterion?

Middle meningeal artery
Grooves internal aspect of pterion

15

What does the middle meningeal artery supply?

Meninges and cranial bones

16

What are the two parts of the frontal bone?

Vertical part forms forehead
Horizontal/orbital plate forms roof of orbit

17

At what point does the front bone turn 90 degrees?

At supraorbital margin

18

Describe the parietal bones

Flat
Relatively rectangular
Molded to brain contour

19

Describe the occipital bone

Flat
Molded to shape of brain posteriorly

20

What is the midline project of the occipital bone called?

External occipital protuberance

21

Describe the squamous part of the temporal bone

Flat
Molded to lateral aspect of brain

22

What are the four processes of the temporal bone?

Zygomatic
Styloid
Mastoid
Petrous

23

Describe the zygomatic process

Extends anteriorly
Articulates with zygoma
Creates zygomatic arch

24

What is the zygoma?

Cheek bone

25

Describe the styloid process

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

Describe the mastoid process

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

27

Describe the petrous process

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

28

Describe the sphenoid bone

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

29

Describe the body of the sphenoid bone

Not solid piece of bone
Pituitary gland sits in cavity

30

Describe the wings of the sphenoid bone

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

31

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

Superior orbital fissure

32

What does the superior orbital fissure do?

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

33

What are the two legs of the sphenoid bone called?

Pterygoid plates

34

Are the pterygoid plates part of the cranial floor?

No

35

Generally describe the inferior aspect of the brain

Not flat
Step appearance

36

How many pairs of cranial nerves are there?

12

37

Where do the cranial nerves emerge from?

Inferior aspect of brain

38

Is the cranial floor flat?

No, it's stepped

39

Why are there holes in the cranial floor?

To allow exit of cranial nerves

40

How are the fossae of the cranial floor arranged?

In stepwise configuration

41

What does the anterior cranial fossa support?

Frontal lobes

42

Where does the anterior cranial fossa sit?

Above and in front of middle cranial fossa

43

What does the middle cranial fossa support?

Temporal lobes

44

Where does the middle cranial fossa sit?

Behind and below anterior cranial fossa

45

What does the posterior cranial fossa support?

Brain stem
Cerebellum

46

Where does the posterior cranial fossa sit?

Behind and below middle cranial fossa

47

Which bones make up the anterior cranial fossa?

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

48

Where is the ethmoid bone?

Between eyes
Just above nose

49

What is the vertical plate of the ethmoid bone called?

Cristagalli

50

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

Cribiform plate

51

Which bones make up the middle cranial fossa?

Greater wing of sphenoid anteriorly
Petrous part of temporal bone inferiorly = edge

52

Which bone makes up the posterior cranial fossa?

Occipital bone

53

What are the foramenae in the anterior cranial fossa?

Cribiform plate

54

What are the foramenae in the middle cranial fossa?

Hypophysial fossa
Optic canal
Superior orbital fissure
Foramen rotundum
Foramen ovale
Foramen spinosum

55

What are the foramenae in the posterior cranial fossa?

Internal acoustic meatus
Jugular foramen
Hypoglossal canal
Foramen magnum

56

What structure goes through the cribiform plate?

Olfactory nerve

57

What structure goes through the hypophysial fossa?

Pituitary gland

58

What structures go through the optic canal?

Optic nerve
Ophthalmic nerve

59

What structures go through the superior orbital fissure?

Nerve to extraocular muscles
Branches of trigeminal nerve

60

What structure goes through the foramen rotundum?

Maxillary nerve

61

What structure goes through the foramen ovale?

Mandibular nerve

62

What structure goes through the foramen spinosum?

Middle meningeal artery

63

What structures go through the internal acoustic meatus?

Facial nerve
Vestibulocochlear nerve

64

What structures go through the jugular foramen?

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

65

What structure goes through the hypoglossal canal?

Hypoglossal nerve

66

How are the foramenae of the middle cranial fossa arranged?

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

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

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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