Blood Supply, Hemorrhage, and Herniation

Question 1

What are the parts of the internal carotid artery?

Answer 1

Cervical, petrous, cavernous, and cerebral parts

Question 2

What is the cervical part of the ICA?

Answer 2

Bifurcation to the carotid canal

Question 3

What is the petrous part of ICA?

Answer 3

Carotid canal in the petrous part of the temporal bone upward and medially above the foramen lacerum

Question 4

What is the cavernous part of ICA?

Answer 4

In the cavernous sinus

Question 5

What surrounds the cavernous part of the ICA?

Answer 5

Sympathetic plexus and CNs III, IV, V1, and VI

Question 6

What are the parts of the vertebral artery?

Answer 6

Cervical, atlantic, and intracranial parts

Question 7

What is the cervical part of the vertebral artery?

Answer 7

Transverse foramina of first 6 cervical vertebrae

Question 8

What is the atlantic part of the vertebral artery?

Answer 8

Perforates the dura and arachnoid mater; passes through foramen magnum

Question 9

What is the intracranial part of the vertebral artery?

Answer 9

In the cranium; unite with other side at caudal border of pons to form the basilar artery

Question 10

What arteries make up the Circle of Willis?

Answer 10

2 anterior cerebral, 2 ICA, 2 posterior cerebral, anterior communicating, and 2 posterior communicating

Question 11

What percentage of lesions to nerves come from issues with the vasculature?

Answer 11

50%

Question 12

What does the anterior cerebral artery supply?

Answer 12

Supplies most of the medial and superior surface of the frontal and parietal lobes

Question 13

What does the middle cerebral artery supply?

Answer 13

Supplies lateral surface of frontal and parietal lobes and the superior part of temporal lobe

Question 14

What does the posterior cerebral artery supply?

Answer 14

Supplies the occipital lobe and the inferior temporal lobe

Question 15

What is the epidural space?

Answer 15

Potential space between cranium and periosteal dura

Question 16

What is the subdural space?

Answer 16

Potential space between dura and arachnoid mater

Question 17

What is the subarachnoid space?

Answer 17

Real space between the arachnoid and pia mater; contains CSF, arteries, and veins

Question 18

What are some causes of herniation syndromes?

Answer 18

Hemorrhage, mass/tumor, trauma, abscess, infection, and/or metabolic conditions

Question 19

What is the supratentorial compartment?

Answer 19

Above the tentorium and divided into right and left by the falx cerebri

Question 20

What is the infratentorial compartment?

Answer 20

Below the tentorium cerebelli

Question 21

What is the tentorial notch?

Answer 21

Continuation of the supra and infratentorial compartment

Question 22

What is a subfalcine (cingulate, falcine, falx) herniation?

Answer 22

Occurs in supratentorial compartment; displaces brain tissue under the falx cerebri; may compress anterior cerebral artery, frontal lobe, parietal lobe; may evolve into a transtentorial herniation

Question 23

What is a transtentorial (central) herniation?

Answer 23

Brain is displaced downward toward tentorial notch; compromises the upper brainstem, CN III, and possibly lower structures; may also compress basilar artery and posterior cerebral arteries; results in decorticate and decerebrate rigidity

Question 24

What is a uncal herniation?

Answer 24

Uncus and usually portions of parahippocampal gyrus are extruded over the edge of tentorium cerebelli and through the tentorial notch; impinges on the brain

Question 25

What is a tonsilar herniation?

Answer 25

Herniation of cerebellar tonsils through the foramen magnum; leads to compression of the medulla and upper cervical spinal cord

Question 26

In a epidural hematoma, where does it bleed into? What is the common site this occurs? What is the source of the bleeding? What are the clinical signs? What is the treatment?

Answer 26

Bleeds Into: epidural space between skull and dura mater

Common Site: fracture of squamous temporal bone or pterion

Source: middle meningeal artery

Signs: momentary unconsciousness followed by lucid period of hours to 1-2 days then unconsciousness

Treatment: surgical

Question 27

In a subdural hematoma, where does it bleed into? What is the occurrence that causes this to happen? What is the source of the bleeding? What are the clinical signs? What is the treatment?

Answer 27

Bleeds Into: between dura and arachnoid mater

Occurrence: head strikes fixed object or during an assault

Source: venous, usually cortical veins opening into superior sagittal sinus

Signs: slower accumulation of blood due to pressure and often self-limiting

Treatment: surgical

Question 28

For a subarachnoid hemorrhage, when is this commonly found? What is the source of the bleeding? What are the clinical signs?

Answer 28

Commonly Found: severe head injury, but more common in rupture of aneurysm

Source: arterial bleeding from cerebral arteries

Signs: massive bleeding into CSF compartment due to arterial source with headaches and deteriorating level of consciousness

Question 29

What is a intracerebral (subpial) hemorrhage? What is the source? What are the clinical signs?

Answer 29

Bleeding within brain substance (stroke); can be a complication in 2-3% of all head injuries

Source: middle cerebral artery

Signs: hypertension or degenerative arterial disease (commonly seen at autopsy

Question 30

What is vertebral basilar insufficiency?

Answer 30

Reduced blood flow from the vertebral arteries during extreme hyperextension of the head and extreme head rotation (Bow-Hunter’s Syndrome)

Question 31

What is subclavian steal syndrome?

Answer 31

Blood from one vertebral artery goes back down the other vertebral artery to the subclavian; happens when there is an occlusion of the subclavian artery proximal to where the vertebral artery comes off; blood is stolen to supply the upper extremities