Neurology Lab 1 - Module 1 - Blood Supply to the Brain: Page 1 of 5

READINGS:

598-

Gray's Anatomy for Students (Fourth Edition): Pages: 863, 868-882

Vertebral Arteries

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	Begin with the aortic arch.
	Add the brachiocephalic trunk, arising from the anterolateral surface of the aortic arch.
	Add the right subclavian artery, coursing toward the superior thoracic aperture and passing posterior to the anterior scalene muscle.
	Add the left subclavian artery, which arises directly from the aortic arch and ascends superiorly before arching laterally over the first rib.
	Add the right vertebral artery, arising from the first part of the subclavian artery and ascends toward the transverse cervical processes.
	Add the left vertebral artery.

	Add vertebrae C7, T1 and T2 to orient the cervicothoracic junction.
	Add vertebrae C3-C6. The vertebral artery ascends within the foramina transversaria from C6 to C1 which convey the vertebral artery, vertebral vein, and accompanying sympathetic plexus.

	One of the distinguishing features of the cervical vertebra is the presence of the foramen transversarium. Why does the vertebral artery not pass through the foramen transversarium of C7?
Rotate the donor model and notice that to pass through the C7 foramen transversarium would require an acute angular change in the direction of the artery, thereby allowing for kinks in the vertebral artery and possible obstuction of blood flow to the brain. You can easily see this by rotating the cadaver 90 degrees. Only the accessory vertebral veins typically enter C7's foraminae.

Step 9	Add the atlas (C1).
	Using the Rotate tool, rotate the cadavar for a posterior view of the vertebral arteries curving around the atlas. You may want to Highlight the atlas to see this better.