Session 1: Cranium, Meninges and Brain Flashcards Preview

Year 2 - LCRS - Anatomy of the Head, Neck and Spine > Session 1: Cranium, Meninges and Brain > Flashcards

Flashcards in Session 1: Cranium, Meninges and Brain Deck (54)
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1
Q

How many bones are there in the skull?

A

22 (excl. ossicles of the ear)

2
Q

What are the components of the skull?

A
  • Mandible
  • (Neuro)Cranium: made up of vault and base
  • Viscerocranium
3
Q

What are the bones of the cranium?

A
  • frontal
  • parietal (2x)
  • temporal(2x)
  • occipital (2x)
  • ethmoid
  • sphenoid
4
Q

What are the facial bones of the skull?

A
  • maxilla (2x)
  • zygoma (2x)
  • nasal (2x)
  • lacrimal (2x)
  • vomer
  • inferior conchae (2x)
  • palatine (2x)
  • mandible
5
Q

What are sutures in the skull?

A

fibrous joints permitting little or no movement.

6
Q

What are the 2 openings in the skulls of newborns called? When do they close?

A
  • anterior fontanelle (closes between 18-24 months of age)

- posterior fontanelle (closes during the first 2-3 months)

7
Q

What are the skull sutures called?

A
  • coronal suture
  • sagittal suture
  • lambdoid suture
8
Q

Are the fontanelles easy to damage?

A
  • no, contrary to popular belief

- there is tough fibrous tissue

9
Q

What is one of the “functions” of the fontanelles?

A
  • the skull bones have to move as the baby passes through the birth canal
  • this is aided by the fact that the bones are not fused.
10
Q

What are the intersections of the coronal sutures called?

A
  • bregma (coronal and sagittal)

- lambda (sagittal and lambdoid)

11
Q

Which bone is the external acoustic meatus located in?

A

Temporal bone

12
Q

What is the inion?

A
  • It is a protrusion on the posterior part of the skull.

- It is bigger in males than it is in females

13
Q

What are the occipital condyles?

A
  • They sit on the C1 vertebra

- allow nodding of head

14
Q

What are the parts of the base of the skull?

A
  • anterior cranial fossa
  • middel cranial fossa
  • posterior cranial fossa
15
Q

what sits in the posterior cranial fossa?

A

Cerebellum

16
Q

What is ‘ventral’ in neuroanatomy?

A

inferior

17
Q

What are the main parts of the anterior cranial fossa?

A
  • orbital part of the frontal bone
  • spehnoid
  • cribriform plate containing foramina

note: there are 2 depressions in the frontal lobe because it sits in the orbital part of the frontal bone where the eyes are, bone is curved because eyes are underneath.

18
Q

What bones make up the middle cranial fossa?

A
  • sphenoid bone
  • temporal bone
  • parietal bone
  • foramina
19
Q

Where is the foramen magnum located?

A

in the posterior cranial fossa

20
Q

What bones make up the posterior cranial fossa?

A
  • occipital bone
  • temporal bone
  • pariteal bone
  • foramen magnum
  • other foramina
21
Q

Approximately, in what order are the cranial nerves positioned?

A

From 1 to 12 from rostral to caudal

22
Q

What passes through the cribriform plate?

A
  • olfactory nerve fibres

- ‘‘cribriform’’ = lat. ‘‘perforated’’ (cribrum = sieve)

23
Q

What passes through the optic canal?

A
  • Optic nerve (including central artery of retina)

- ophthalmic artery

24
Q

What passes through the superior orbital fissure?

A
  • Oculomotor (III)
  • trochlear (IV)
  • ophthalmic div. of V (V1)
  • abducent (VI)
  • sup ophthalmic vein
25
Q

What passes through the foramen rotundum?

A
  • maxillary division of V (V2)
26
Q

What passes through the foramen ovale?

A
  • mandibular division of V (V3)
27
Q

What passes through the foramen lacerum; spehnopetrosal fissure?

A
  • internal carotid artery
28
Q

What passes through the foramen spinosum?

A
  • Middle meningeal artery & vein
29
Q

What passes through the carotid canal, internal aperture?

A
  • internal carotid artery
30
Q

What passes through the internal acoustic meatus?

A
  • facial (VII)
  • vestibulocochlear (VIII)
  • labyrinthine artery
31
Q

What passes through the jugular foramen?

A
  • Glossopharyngeal (IX)
  • Vagus (X)
  • Accessory n (XI)
  • sigmoid sinus → int jugular v
32
Q

What passes through the hypoglossal canal?

A
  • Hypoglossal nerve (XII)
33
Q

What passes through the foramen magnum?

A
  • Vertebral arteries
  • medulla of brain
  • spinal roots of accessory nerve
34
Q

What are the layers of meninges?

A
  • dura mater
  • arachnoid mater
  • pia mater
35
Q

What are the qualities of the dura mater?

A
  • thick
  • inelastic
  • 2 layers (meningeal and periosteal)
36
Q

What are the qualities of the arachnoid mater?

A
  • elastic

- spider like projections

37
Q

What are the qualities of Pia mater?

A
  • innermost
  • thin
  • delicate layer
38
Q

What space is filled with CSF?

A

the subarachnoid space

39
Q

What are the differences regarding epidural space in the brain and in the vertebral column?

A
  • lack of epidural space in the brain
  • large epidural space in the vertebral column

-> correct?

40
Q

What happens as the meninges exit through the foramen magnum?

A
  • the outermost layer is lost, it fuses with the skull

- inner layer (meningeal) of dura continues down the vertebral column

41
Q

What is the purpose of dural folds?

A
  • prevent movement of the brain

- provide spaces where blood can drain back into the venous system.

42
Q

Where does the inner layer of the dura mater peel away?

A

e. g.
- down the longitudinal fissure
- provide spaces where blood can drain back into the venous system

43
Q

What is the falx cerebra?

A
  • main dural fold
  • sickle shaped double layer
  • at the top: superior sagittal sinus
44
Q

What is the superior sagittal sinus?

A
  • runs along the midline on the superior part of the brain
  • where veins drain into the venous system to drain into the jugular veins
  • it is penetrated by the arachnoid mater so that the CSF can be reabsorbed into the venous system before the jugular
45
Q

What is the downside of the sheets?

A
  • if there is a space occupying lesion (e.g. tumor, blood, oedema, cyst) in any compartment it can raise IC pressure and lead to herniation of part of the brain
46
Q

Subfalcine herniation

A

not usually clinically significant

47
Q

Uncal herniation

A
  • affects midbrain

=> unconsciousness

48
Q

Tonsillar herniation

A
  • affects medulla

=> cardiorespiratory failure

49
Q

Blood supply to the meninges

A
  • rich blood supply

- Middle meningeal artery (MMA) inside the cranial cavity, supplies the meninges

50
Q

MMA

A
  • middle meningeal artery
  • branches off of the maxillary artery which itself branches off of the external carotid
  • runs along the pterion -> if that is fractured a large epidural bleed could occur
51
Q

Pterion

A
  • region where the frontal, parietal, temporal, and sphenoid bones join together
  • fragile, thin bone
  • if this area is fractured a large epidural bleed with disastrous consequences could occur
52
Q

Why can infections outside (e.g. scalp) sometimes get into the cranial cavity?

A
  • there are veins that traverse to outside of the skull to the cranial cavity
  • some parts of skull and face drain not via the system external to the cranial cavity but internal to the cranial cavity

=> infections on the outside can sometimes get inside the cranial cavity

53
Q

Confluence of sinuses

A
  • ## connecting point of the superior sagittal sinus, straight sinus, and occipital sinus
54
Q

Cavernous sinus

A
  • clinically relevant because bleeds in the cavernous sinus can affect many cranial nerves