5. Vertebral artery(VA)
Subclavian artery
Ascend in foramina transversaria
Upper six cervical vertebra
Enter cranial cavity thro foramen
magnum
Anterolateral aspect of medulla
Divided into 4 parts: V 1 to V 4
8. “SUBCLAVIAN STEAL”
• Subclavian occluded
proximal to origin of
vertebral.
• Leads of reversal in the
direction of blood flow in the
ipsilateral vertebral artery.
• Exercise of ipsilateral arm
may increase demand on
vertebral flow, leading to
posterior circulation TIAs.
9. Branches of VA
Anterior spinal artery
◦ Join at mid medullary level
◦ Descend on ventral midline of spinal cord
◦ Supply triangular area of medulla
oblongata
10. Branches of VA(contd…)
Posterior inferior cerebellar artery
◦ Largest branch
◦ Ascends behind the roots of the ix & x cr.
Nerves
◦ Turns laterally into cerebellar vallecula
◦ Medial and lateral branches
◦ Supply medulla oblongata dorsal to
olivary nucleus & lateral to xii nucleus
15. Basilar artery(BA)
Arise at Lower border of pons
Extend upto upper border of pons
Large median vessel formed by union
of vertebral arteries
Terminates by dividing into 2 posterior
cerebral arteries at the
interpeduncular fossa
16. Branches of Basilar artery
Pontine branches
Anterior inferior cerebellar artery
◦ Lower part of BA
◦ Labyrinthine artery
◦ Supplies inferior cerebellar surface
anterolaterally
◦ Anastomose with PICA
◦ Few branches to inferolateral pons
Superior cerebellar artery
17. Branches of Basilar
artery(contd..)
Superior cerebellar artery
◦ Distal portion of BA
◦ Oculomotor nerve separates it from
posterior cerebral artery
◦ Trochlear nerve laterally
21. Posterior Cerebral
Artery(PCA)
Terminal branch of basilar artery
Surgical nomenclature identifies 3
segments:
◦ P1 basilar bifurcation to post
communicating a
◦ P2 portion in perimesencephalic cistern
◦ P3 portion in the calcarine fissure
Supplies temporal and occipital lobes
◦ Has cortical and perforate/central
branches
22. PCA: Cortical Branches
Temporal branches usually two supply
◦ Uncus
◦ Parahippocampus
◦ Medial and lateral occipetotemporal gyri
Occipital branches supply
◦ Cuneus
◦ Lingual gyrus
◦ Posterolateral surface of the occipetal
lobe
29. Blood supply of the spinal
cord
Anterior spinal artery in anterior
median fissure
Two Posterior spinal arteries in the
posterolateral sulcus
Arterial vasocorona an arterial plexus
in the pia mater
31. Main source of blood
Main source of blood to spinal arteries
Vertebral arteries upto cervical
segments
Radicular ateries that reach the cord
along spinal nerve roots