|
Year |
2001 |
|---|---|
|
Question Number |
146. |
|
Category |
Select |
Question
When placing lateral mass screws in the midcervical spine, where is the vertebral artery located in relation to the starting point for screw insertion?
1. medial
2. lateral
3. anterior
4. posterior
5. superior
Figures
Answer (click for answer)
The answer is 3. The vertebral arteries represent the major blood supply to the cervical spine and spinal cord. The paired vertebral arteries arise bilaterally as the first and largest branches of the subclavian arteries at the level of T1. The arteries enter the foramen transversaria of C6 and ascend passing posterior to the lateral mass of the altas. In the midcervical spine, the vertebral arteries run in the foramen transversaria which is anterior to the lateral masses. This relationship is best demonstrated on CT axial views of the midcervical spine. The vertebral arteries are anterior to the starting point for lateral mass screws (placed through a posterior approach.)
Reference: Amundson, G. "Vascular Anatomy of the Spine," in A. Levine Spine Trauma, 1998, pp. 61-74