Blood Supply Flashcards
Location of Circle of Willis?
Interpeduncular Fossa
In the base of brain
Formation of Circle of Willis?
Anterior - Ant Communicating A. Anterolateral- Ant. Cerebral A. Lateral - Int. Carotid A. Posterolateral- Posterior Communicating A. Posterior - Posterior Cerebral A.
Function of Circle of Willis?
- Equalize pressure of blood flow on both sides of the brain
- Provide collateral circulation in case of blockage of any of its components
Course of Internal Carotid Artery?
4 parts
•Cervical - Origin from Common Carotid Artery to the Carotid canal
•Petrous- Traverses Carotid canal in Petrous temporal bone
•Cavernous-Traverses Cavernous Sinus
•Cerebral- Pierces the dura on the roof of Cavernous sinus and ends just lateral to Optic Chiasma below Ant. Perforated Substance
Course of Vertebral Artery?
4 parts
•1st part - origin from subclavian Artery to the foramen transversarium of C6 vert
- 2nd part- traverses foramina transversaria of C6-C1
- 3rd part - Lies in the Posterior arch of atlas in suboccipital triangle
- 4th part - enters cranial cavity through Foramen magnum under the free margin of Atlanta-occipital membrane
Termination:
It pierces the dura mater, enters subarachnoid space, winds round ventrolateral aspect of medulla & unites with its fellow at the lower border of pons to form the Basilar Artery.
Arteries Supplying Spinal Cord?
1 Anterior Spinal Artery
2 Posterior Spinal Arteries
Radicular Arteries
Pia mater of spinal cord has an arterial plexus called Arteria Vasocorona
Venous drainage of spinal cord?
6 groups
Median Channels - Anteromedian vein and Posteromedian Venous channels
Anterolateral
Posterolateral
They drain into the radicular veins -> Internal vertebral venous plexus-> segmental veins
Branches of Vertebral Artery?
5 branches
1) PICA
2) Posterior Spinal Artery
3) Anterior Spinal Artery
4) Meningeal Branches
5) Medullary branches
Branches of Basilar Artery?
5 branches
1) AICA
2) Superior Cerebellar
3) Labyrinthine Arteries
4) Pontine Branches
5) Posterior Cerebral Artery
Branches of Internal Carotid Artery?
5 branches
1) Opthalmic A
2) Anterior Choroidal A
3) Posterior Communicating A
4) Anterior Cerebral A
5) Middle Cerebral A
Branches of Circle of Willis?
- Cortical
ACA- Frontopollar, Orbital, Pericallosal, Callosal-marginal
MCA - Temporal, Parietal, Frontal
PCA- Temporal, Occipital
2. Central
•Anteromedial -1 group
•Anterolateral - 2 groups
•Posteromedial - 1 group
•Posterolateral - 2 groups
- Choroidal
•Anterior Choroidal - Inf horn of Lat Vent
•Posterior Choroidal - Lateral and 3rd vent
• PICA - 4th vent
Areas of brain devoid of BBB?
- Area postrema in 4th ventricle
- Posterior lobe of pituitary
- Supraoptic Recess
- Pineal body
- Choroid Plexus
Main artery supplying Superolateral Surface of Cerebrum. Exceptions?
2/3rd of the surface by Middle Cerebral Artery.
Includes greater parts of primary motor and sensory areas, Frontal eye field. In the left (dominant) hemisphere includes Broca and Wernicke’s speech areas.
Exception:
•Narrow strip of 2cm width extending from frontal pole to Parieto-occipital sulcus is supplied by ACA. Includes upper parts of primary motor and sensory areas.
•Inferior Temporal gyrus except the Temporal pole and the Occipital lobe is supplied by the PCA. The area of supply of PCA includes posterior parts of visual area.
Main artery supplying Medial Surface of Cerebrum? Exception?
Anterior Cerebral Artery.
Exception:
•Medial aspect of occipital and temporal lobes except temporal pole supplied by PCA
•Temporal pole supplied by MCA
Main artery supplying inferior surface of cerebrum? Exception?
Posterior Cerebral Artery.
Exception:
•Medial 1/3rd of Orbital Surface supplied by ACA
•Lateral 2/3rd of orbital surface and Anterior-most part of Tentorial surface supplied by MCA
(Remaining part of tentorial surface is by PCA)
