Cranial Meninges and Intracranial Circulation Flashcards Preview

Structure and Function Test 1 > Cranial Meninges and Intracranial Circulation > Flashcards

Flashcards in Cranial Meninges and Intracranial Circulation Deck (80):
1

Within the cranial cavity, the dura matter is composed of which two layers?

Periosteal dura, and meningeal dura

2

Lines the inner surface of the skull and serves as the periosteum (Endosteum)

PEriosteal Dura

3

There is normally no space between the periosteal dura and the bone of the skull. However under abnormal circumstances (i.e. bleeding) A space is created there called the

Epidural (or extradural) space

4

The meningeal dura is fused to the periosteal dura for much of its surface, but in some regions it separates from the periosteal dura to turn internally to form

Dural Septa

5

The major dural septa include the

Falx cerebri, Falx cerebelli, and Tentorium cerebelli

6

The Falx cerebri, Falx cerebelli, and Tentorium cerebelli are all composed of only

Meningeal dura

7

Lies between the two cerebral hemispheres

Falx cerebri

8

Lies between the two cerebellar hemispheres

Falx ceribelli

9

Lies between the cerebellum and the occipital lobe of the cerebrum

Tentorium cerebelli

10

Lie between periosteal dura and the meningeal dura in the regions where the two layers separate

Dural Venous sinuses

11

Dural venous sinuses are also found within reflections of the

Meningeal dura

12

Dural sinuses are lined with the same epithelium that is found lining the

Veins of the body

13

Lies between the periosteal dura and meningeal dura at the root of the falx cerebri

Superior saggital sinus

14

Lies within a reflection of the meningeal dura at the free edge of the falx cerebri

Inferior saggital sinus

15

Lies between periosteal dura and meningeal dura at the root of the falx cerebelli

Occipital sinus

16

Lies within
meningeal dura at the intersection of the falx cerebri and tentorium cerebelli

Straight sinus

17

Located between periosteal and meningeal dura at the point where the superior sagittal, occipital and straight
sinuses meet

Confluens of sinuses

18

Lies between periosteal and meningeal dura at the attachment of the
tentorium cerebelli

Transverse sinuses

19

The anterior continuation of the transverse sinuses

-Drains into the jugular bulb

Sigmoid sinuses

20

Lie between periosteal and meningeal dura forming the lateral walls of the pituitary fossa`

Cavernous sinuses

21

Connects the cavernous sinus to the sigmoid sinus

Superior petrosal sinuses

22

Drains the cavernous sinus into the jugular bulb

Inferior petrosal sinuses

23

Carry most of the venous drainage from the brain

Dural sinuses

24

The dural sinuses drain into the

Internal jugular vein

25

The dural sinuses drain into the internal jugular vein and also communicate with veins of the face, scalp, and neck through

Emissary veins

26

Do not contain valves

Emissary veins

27

Since emissary veins do not contain valves, blood can flow in either direction. Thus, these veins can be pathways for the

Spread of infection from superficial regions of the face and scalp into the cranial cavity

28

Intimately fused to the brain

-Follows the sulci and gyri of the cerebral cortex

Pia matter

29

Does not enter the sulci. It is adherent to the inner surface of the meningeal dura

Arachnoid matter

30

Are the dura and arachnoid surfaces fused together?

No

31

The arachnoid is pressed against the dura by

Cerebrospinal fluid pressure

32

There is usually no space between the

Dura and arachnoid

33

Highly vascularized tissue found in the ventricles of the brain

-Secrete cerebrospinal fluid

Choroid plexuses

34

The upward continuations of the central canal of the spinal cord

Ventricles of the brain

35

How many ventricles of the brain are there

Four: two lateral, the midline third, and midline fourth ventricles

36

The midline third ventricle is located in the

Diencephalon

37

The midline fourth ventricle is located

Between the cerebellum and pons and the medulla

38

CSF produced in the lateral ventricles enters the third ventricle through the

Interventricular foramina (of Monro)

39

From the third ventricle, CSF passes to the fourth ventricle through the

Cerebral aqueduct (of Sylvius)

-In the midbrain

40

From the fourth ventricle, CSF may continue into the central canal, but mostly it enters the

Subarachnoid space

41

CSF enters the subarachnoid space from the 4th ventricle through which three openings?

2 Lateral foramina (of Luschka) and 1 MEdian foramen (of Magendie)

42

CSF is resorbed into the venous system at the

Arachnoid granulations

43

Tufts of arachnoid that come into close contact with thinned out regions of the dural wall of the superior saggital sinus

Arachnoid granulations

44

Approximately how much CSF is there in the subarachnoid space and ventricles at any one time?

125-150 mL

45

How much CSF is secreted in the average adult each day?

450 - 500 mL

46

CSF in the subarachnoid space normally has a pressure of bout

80-120 mmH20

47

An abnormal increase in intracranial CSF pressure results in

Hydrocephalus

48

What are the two major categories of hydrocephalus?

1.) Communicating hydrocephalus
2.) Non-communicating (or obstructive) hydrocephalus

49

CSF is able to pass from the ventricles to the subarachnoid space, but resorption into the venou ssystem does not keep pace with CSF production

Communicating hydrocephalus

50

CSF produced in the ventricles is obstructed in its passage to the subarachnoid space and thus there is diminished resorption into the venous system

Non-communicating (obstructive) Hydrocephalus

51

Communicating hydrocephalus is usually caused by a defect in

Resorption

52

Non-communicating hydrocephalus is most commonly caused by

Narrowing of the cerebral aqueduct

53

Non-communicating hydrocephalus is less commonly caused by an obstruction in the

Lateral and/or median foramina or the interventricular foramen

54

The brain receives its blood supply from

2 vertebral and 2 internal carotid arteries

55

The vertebral arteries supply mostly the

Brainstem, cerebellum, and occipital lobe of the cerebrum

56

Supply most of the remainder of the brain

Internal carotid arteries

57

These 4 arteries anastomose with eachother to form the

Cerebral arterial circle (CIrcle of Willis)

58

At the pons-medulla junction, the two vertebral arteries join to form the

Basilar artery

59

At the pons-midbrain junction, the basilar artery divides into

2 Posterior cerebral arteries

60

After exiting from the cavernous sinus, the internal carotid artery divides into the

Anterior cerebral artery, middle cerebral artery, and posterior communicating artery

61

Connect the two internal carotid arteries to the two posterior cerebral arteries

Right and left posterior communicating arteries

62

The two anterior cerebral arteries are connected by the

-forms the communication between right and left carotid system

Anterior communicating artery

63

The cerebral arteries are bound to the pia matter and therefore are in the

Subarachnoid space

64

The middle meningeal artery (branch of the maxillary artery) enters the cranial cavity through the

Foramen spinosum

65

Within the cranial cavity, branches of the middle meningeal artery lie between the

Inner surface of the skull and periosteal dura (tightly bound to the dura)

66

These branches may be injured by trauma to the overlying skull resulting in arterial bleeding into the plane between the periosteal dura and the skull. This is called an

Epidural hematoma

67

What is the most common sight of injury for an epidural hematoma?

Lateral side of the head in the region of the pterion

68

Patients with an epidural hematoma will often have a period of time known as the

Lucid interval

69

During this lucid period, the size of the hematoma is increasing until the increased cranial pressure again causes

Unconsciousness

70

The cortex of the brain has venous drainage through cortical veins which drain into dural venous sinuses, primarily the

Superior saggital sinus

71

These veins "bridge" across the subarachnoid space to penetrate the arachnoid and then the

Dura

72

Tearing of these bridging veins by force or rapid deceleration at the site where they are anchored to the dura results in a

Subdural hematoma

-Separates arachnoid and dura creating subdural space

73

Onset of a subdural hematoma is slower than an epidural hematoma because of the

Slower leaking blood from lower pressure veins

74

Because the periosteal dura is very tightly attached to the bone of the skull at the suture lines, what type of hematoma does not cross suture lines?

Epidural hematoma

75

Can cross suture lines

-Allows clinicians to differentiate between types of hematoma on imaging

Subdural hematoma

76

The arteries that provide blood supply to the brain are bound in the pia matter on the surface of the brain and thus are in the

Subarachnoid space

77

Rupture of any of these arteries as a ruptured cerebral aneurysm or head trauma will result in a

Subarachnoid hemorrhage

78

In a subarachnoid hemorrhage, arterial blood enters the subarachnoid space and mixes with

CSF

79

How can a subarachnoid hemorrhage be diagnosed?

By presence of blood in CSF in a spinal tap

80

What are some symptoms of a subarachnoid hemorrhage?

Severe rapid onset headache (worst of life), and may have vomitin, seziures, disorientaton or other neurological signs/symptoms

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