Circle of Willis and Regions of the Brain Flashcards
Identify the two main arteries that supply the COW
Internal Carotid: enters the skull through the carotid canal, located in the temporal bone
Vertebral Artery: enters posterior brain through foramen magnum
A 45 yo male suffers a stroke with paralysis on the right side of his body. CT shows a cerebral arterial hemorrhage has interrupted blood supply to the temporal lobe of the left cerebral hemisphere. Which vessel is involved?
middle cerebral atery
A 45 yo male suffers a stroke with paralysis on the right side of his body. CT shows a cerebral arterial hemorrhage has interrupted blood supply to the temporal lobe of the left cerebral hemisphere.
The scenario above referred to an arterial bleed—a hemorrhagic stroke or hemorrhagic cerebral vascular accident (CVA). What is an arterial blockage called?
This CVA is referred to as ischemic. Ischemia occurs when an artery is blocked –usually by blood clot or plaque.
What deficits would you expect to be more prevalent from a cerebral vascular accident of the middle cerebral artery?
Contralateral hemiparesis (weakness) and sensory disturbance of the face, upper and lower extremities (usually more pronounced weakness of the face and arm). There can be expressive aphasia (Broca’s area).
What deficits would you expect to be more prevalent from a cerebral vascular accident of the Anterior cerebral artery (ACA)?
The ACA supplies most of the frontal lobes. Damage to this area usually involves problems with thought, behavior/personality, and also strength of the opposite leg.
What deficits would you expect to be more prevalent from a cerebral vascular accident of the Posterior cerebral artery?
A CVA here will affect many aspects of vision. A special note about vision: each eye has a left and right field. A right occipital lobe CVA may cause loss of vision to the left side of both eyes.
This is called homonymous hemianopsia. However, the same thing can happen with a lesion of the right optic tract.
List the four main regions of the brain and identify primary function.
Frontal Lobe: largest anterior: Motor cortex
Occipital Lobe: most posterior: visual
Temporal Lobe: auditory
Parietal Lobe: sensory
what bones form the pterion?
Frontal, parietal, sphenoid, and temporal
A baseball player is hit between the eye and ear (pterion) and immediately loses consciousness. He wakes momentarily then becomes comatose and is rushed to the hospital. A CT is positive for a skull fracture and hemorrhaging between the dura and cranial bones requiring immediate surgery. A hole is bored into his skull to relieve pressure. Within a few hours he regains consciousness and has an uneventful recovery.
The hemorrhage would be described as:
epidural
Which artery is suspect for the hemorrhage in the pterion?
middle meningeal artery
describe the meningeal layers of the brain
1) DURA The tough outer membrane.
2) ARACHNOID A thin non vascular membrane which surrounds the brain loosely. The sub arachnoid space is a real space which contains CSF.
3) PIA Soft delicate membrane closely applied to the brain tissue. It carries blood vessels which supply the brain with blood.
what are the 3 dural folds?
tentorium cerebelli
falx cerebelli
falx cerebri
tentorium cerebelli location
Separates the cerebellum from the occipital poles of the cerebral hemispheres and encloses the transverse sinus. It attaches to the anterior and posterior clinoid processes.
falx cerebelli location
Relatively small, it lies between the 2 cerebellar hemispheres in the median plane. It is attached to the internal occipital crest and superiorly to the inferior aspect of the tentorium. It contains the occipital sinus
falx cerebri location
A sickle shaped membrane lying medially between the 2 cerebral hemispheres. Anteriorly it attaches to the crista galli of the ethmoid bone. Posteriorly it is fused with the tentorium.
