Arterial Supply

Question 1

The brain receives its blood supply from what four arteries?

Answer 1

• 2 vertebral arteries
• 2 internal carotid arteries

Question 2

The vertebral arteries enter the brain via:

Answer 2

foramen magnum

Question 3

The internal carotid arteries enter the brain via:

Answer 3

carotid canals

Question 4

Subclavian Steal Syndrome:

Answer 4

• Partial occlusion of subclavian artery proximal to where vertebral artery branches off.
• Blood flow in vertebral artery on side of occlusion will switch directions due to decreased blood pressure in it, which will allow for blood flow to the upper limb.

Question 5

In what syndrome is blood is being stolen from the brain’s blood supply in order to supply blood to the upper limb?

Answer 5

subclavian steal syndrome

Question 6

Vertebral arteries merge to form the singular basilar artery where?

Answer 6

junction of the medulla and pons

Question 7

Where does the basilar artery bifurcate into the two posterior cerebral arteries?

Answer 7

• upper end of the pons
• (pons-midbrain junction)

Question 8

The Circle of Willis has connections between:

Answer 8

• right and left carotid systems
• carotid and verterbrobasilar systems

Question 9

Diagram of cerebral arterial supply:

Answer 9

Question 10

Blood supply to the posterior spinal cord:

Answer 10

• posterior spinal arteries
• branches off vertebral arteries

Question 11

Blood supply to the anterior spinal cord:

Answer 11

• anterior spinal arteries
• branches off vertebral arteries

Question 12

Blood supply to the medulla:

Answer 12

• anterior spinal arteries
• posterior inferior cerebellar arteries

ALL ABOVE BRANCHES OF VERTEBRAL ARTERIES

Question 13

Blood supply to the pons:

Answer 13

• pontine arteries
• superior cerebellar artery
• anterior inferior cerebellar artery

ALL ABOVE BRANCHES OF BASILAR ARTERY

Question 14

What arteries connect the two internal carotid arteries to the two posterior cerebral arteries, thus forming the communications between the vertebral system and the carotid system?

Answer 14

posterior communicating arteries

Question 15

What arteries connect the two anterior cerebral arteries, thus forming the communication between the right carotid system and the left carotid system?

Answer 15

anterior communicating arteries

Question 16

What artery is a direct continuation of the internal carotid artery?

Answer 16

middle cerebral artery

Question 17

Plaques that form in the internal carotid artery are most likely to travel into which cerebral artery?

Answer 17

• middle cerebral artery
• straight path since middle cerebral artery is direct continuation of the internal carotid

Question 18

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

Answer 18

foramen spinosum

Question 19

Epidural hematoma:

Answer 19

• accumulation of blood between the periosteal dura and the skull, which creates an epidural space.

Question 20

Why do epidural hematomas expand inward?

Answer 20

• initially expand laterally, separating the periosteal dura from the skull until they reach a suture line.
• Periosteal dura does not detach from suture lines, so the epidural space expands into the brain cavity.

Question 21

What injury is most likely to cause an epidural hematoma?

Answer 21

• lateral skull fracture
• thinnest part of the skull, severs middle meningeal artery.

Question 22

“lucid interval”

Answer 22

unique to epidural hematomas

1. initial concussive force causes LOC.
2. patient regains consciousness and has a lucid period.
3. size of the hematoma increases
4. increased intracranial pressure again causes LOC

Question 23

Subdural hematoma:

Answer 23

• accumulation of blood between the arachnoid and the meningeal dura

Question 24

What injury is most likely to cause a subdural hematoma?

Answer 24

• acceleration/deceleration injuries that cause rapid movement of the brain.
• cortical cerecral “bridging” veins tear where they connect to the dura to drain into the superior sagittal sinus.

Question 25

Which injury typically has a faster onset of symptoms, epidural hematoma or subdural hematoma?

Answer 25

• slower in subdural hematomas because of
• the slower leaking of blood from the lower pressure veins (cortical cerebellar “bridging” veins).

Question 26

Can subdural hematomas cross suture lines?

Answer 26

• Yes, because arachnoid is not directly attached to the bone of the skull.
• Subdurals form between arachnoid and meningeal dura.

Question 27

Can epidural hematomas cross suture lines?

Answer 27

• No.
• Epidurals form between periosteal dura and the skull. Periosteal dura does not separate from suture lines.

Question 28

What kind of hematoma is this?

Answer 28

epidural

does not cross suture lines

Question 29

What kind of hematoma is this?

Answer 29

subdural

crosses suture lines

Question 30

The presence of blood in the CSF obtained by spinal tap would be diagnostic of:

Answer 30

subarachnoid hemorrhage

Question 31

Subarachnoid hemorrhage:

Answer 31

• Accumulation of arterial blood entering the subarachnoid space and mixing with CSF.

Question 32

What injury is most likely to cause a subarachnoid hemorrhage?

Answer 32

• aneurism or head trauma
• shearing of arteries that supply blood to the brain and are contained within the pia.

Question 33

Aneurisms tend to occur at:

Answer 33

• points of bifurcation of arteries

Question 34

Most common site of brain aneurism:

Answer 34

• bifurcation between the anterior communicating artery and the anterior cerebral artery.

Question 35

Aneurism treatment:

Answer 35

1. surgical clipping.
2. titanium wiring in aneurism to cause clot.

Question 36

Aneurism symptoms:

Answer 36

• Aneurisms themselves do not cause symptoms.
• Symptoms related to compression of cranial nerves in the immediate area of the aneurism.

Question 37

Patients presenting with visual effects/symptoms may be suffering from:

Answer 37

• an internal carotid aneurism due to optic nerve/chiasm compression.