Neuroanatomy: Brain Vasculature Flashcards
What is the vertebral artery a branch of?
How does it enter the skull?
What does it supply?
Vertebral artery: Enters through the Transverse Foramina of C6 -C1 then enters the skull through the Atlas and Foramen Magnum
Supplies the caudal portions of the brain stem
What are the branches of the internal carotid?
Internal carotid –> Middle cerebral artery and Anterior cerebral artery
Off of the Internal Carotid is a communicating branch that connects to the Basilar artery (posterior communicating branch)
What is the first branch of the Vertebral artery?
Why is this critical?
The Posterior Inferior Cerebellar Artery (PICA)
- Supplies the lateral portion of the Medulla! - Critical because thrombotic strokes will affect this artery –> PICA Infarction
- Supplies the cerebellum as well
What is the Circle of Willis/Arterial Circle?
What do they mean by Cortical and Central branches of the region of the Circle of Willis?
This is a ring of artery around the pituitary gland that is made up of connections by several cerebral arteries
Cortical (circumfrential): Branches that travel into the subarachnoid space and supply outer surface of brain
Central (Ganglionic/Perforating): These branches penetrate into the deep portions of the brain.
What nerve accompanies the Internal Auditory Artery (the first branch from the Basilar artery)?
The Vestibulochochlear nerve
What does the middle cerebral arteries supply?
What are they a continuation of?
The middle cerebral arteries are a direct continuation of the Internal Carotid Artery.
These enter the insular area and come out of the lateral fissure to supply the lateral surface of the cerebral hemisphere
The Central or Perforating branches supply the deep structures of the cerebral hemisphere
What is the clinical significance of the Middle Cerebral Arteries?
- Carry 80% of the blood to the cerebral hemispheres
- Most strokes will affect the middle cerebral artery (both cortical and central branches (superficial and deep))
What does the Anterior Cerebral Artery Supply?
- Lower surface of frontal lobe
- Olfactory bulb/tract
- Medial surface of frontal & parietal lobes
- Corpus Callosum
- A little bit of the dorsolateral surface of the hemispheres
What happens if there is damage to the Anterior Cerebral Arteries?
This artery supplies the pre- and postcentral gyri of the paracentral lobule (motor and sensory cortexes) So there will be paralysis and loss of somatosensory in the lower limbs!
*Contralateral!
What does the middle cerebral artery supply?
The Caudate nucleus, Internal Capsule, The surface of the cortex
Where does the middle cerebral artery run?
Deep in the lateral fissure
What do the Vertebral arteries supply?
- What about the Anterior Spinal artery?
- What about the Posterior Spinal artery?
- Brain stem & Cerebellum
- Supratentorial structures: Diencephalon and Visual Cortex in occipital lobe.
The anterior spinal artery supplies:
-Ventro-medial part of medulla
Ventral-lateral portion of spinal cord
Posterior Spinal arteries supply”
(opposite of anterior spinal)
-Dorso-lateral part of medulla
-Dorso-medial portion of spinal cord
What artery peirces the tentorium and supplies the occipital lobe?
Posterior Cerebral Artery
-Damage can lead to visual problems
Do emobli usually go into the anterior cerebral arteries, posterior communicating arteries, or the middle cerebral arteries?
They usually involve the middle cerebral because it is a direct line.
-Emboli from the heart also end up on the left side of the brain
What is the Internal carotid artery a branch of?
How does it enter the skull?
What does it supply?
Internal Carotid Artery is a branch of the common carotid.
-It enters the skull through the carotid canal and becomes the Anterior & Middle Cerebral arteries
(Anterior supplies medial portion of frontal and parietal lobes)
(Middle supplies lateral portion of the frontal and parietal lobes)
Blocking the Middle Cerebral Arteries leads to what problems?
Paralysis & Sensory Defects in head, arms, and upper body.
*Remember that this is all contralateral (damage in the right hemisphere –> deficits in the left portion of the body)
Damage to the left side of the brain can aslo end up in difficulty with speech/understanding
What do the Posterior Infereior Cerebellar Arteries (PICA) supply?
What is the clinical significance of PICA arteries?
They supply the
- Cerebellum
- Choroid Plexus of the 4th ventrical
- Dorsolateral Medulla
Clinical Significance: Prone to occlusion
-Results in Lateral Medullary PICA syndrome
Why are the Calcarine Branches extremely important?
What would a blockage in the calcarine arteries do?
The calcarine branches supply the Visual cortex.
A blockage would result in blindness in the contralateral visual field
A.K.A. Contralateral Homonymous Hemianopsia
