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Cranial Vascular Anatomy. James Montgomery, DVM September 27, 2010. Major Vessels. Arterial Supply Internal carotid Basilar Venous Return Sinuses of the dura mater (though not confined to the dura in dogs) Dorsal set Unpaired: Dorsal sagittal and straight sinuses
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Cranial Vascular Anatomy James Montgomery, DVM September 27, 2010
Major Vessels • Arterial Supply • Internal carotid • Basilar • Venous Return • Sinuses of the dura mater (though not confined to the dura in dogs) • Dorsal set • Unpaired: Dorsal sagittal and straight sinuses • Paired: transverse sinus • Ventral set • Double, unpaired intercavernous sinus • Paired cavernous, signoid, basilar, and dorsal and ventral petrosal sinuses
Major arterial supply – Internal Carotid • Marks termination of common carotid • Carotid body: chemoreceptor • Highly sensitive to O2 concentration • Also sensitive to CO2 and pH
Major arterial supply – Internal Carotid • Enters petro-occipital fissure and traverses the carotid canal • Then passes ventrally through the foramen lacerum, forms a loop, and re-enters the cranial cavity through the same foramen.
Major arterial supply – Internal Carotid • Perforates one layer of the dura mater and runs through the blood filled cavernous sinus that separates the dura into two layers
Major arterial supply – Internal Carotid • Perforates second layer of dura and the arachnoid, and comes to lie in the subarachnoid space • Trifurcates: • Middle Cerebral • Rostral Cerebral • Caudal Cerebral
Circle of Willis • Formed by the right and left internal carotid arteries and basilar artery • Caudal communicating artery • Leaves the internal carotid after it enters the subarachnoid space and forms the lateral and caudal thirds of the arterial circle before anastomosing with the basilar artery • Rostral, Middle, and Caudal cerebral arteries supply cerebrum • Rostral, and Caudal Cerebellar arteries supply the cerebellum; pontine and medullary branches of the basilar supply the pons and medulla oblongata. • Ensures the maintenance of constant blood pressure in the terminal arteries and provides alternate routes by which blood can reach the brain
Venous Return • Paired: Transverse, Cavernous, Sigmoid, Basilar, and dorsal and ventral petrosal sinuses • Unpaired: Dorsal sagittal, Straight, Intercavernous • Sinuses empty into venous system via multiple routes • Maxillary vein • Basilar sinus • Vertebral vein • Internal jugular vein