Unit 9: spinal/arterial circulation Flashcards
which groove does the anterior spinal artery fit into?
anterior median fissure
where do the posterior spinal arteries get their blood supply? (3)
- vertebral arteries (from above cord)
- cerebellar arteries (2/3) (from above cord)
* AICA
* PICA - intercostal arteries (from lower cord)
what do radicular arteries do? where are they located?
radicular arteries connect intercostal arteries to either the anterior spinal artery or the posterior spinal arteries
radicular arteries are “EITHER/OR”, but they do NOT connect from BOTH the anterior AND posterior on the same level
how many intercostal arteries are there?
24 total
(12 sets)
radicular artery aliases (2)
segmental arteries
medullary arteries
relate the following terms: coronal arteries, SC, colateral circulation
the SC does NOT have as good of colateral circulation as there is in the brain; the coronal arteries are not continuous around the cord.
what percentage of the SC gets blood supplied by the anterior spinal artery? posterior spinal arteries?
75% from anterior s.a.
25% from posterior s.a’s (combined; 12.5% each)
how many posterior spinal veins run along the spinal cord? anterior spinal veins?
3 posterior spinal veins (one midline, two lateral)
1 midline anterior spinal vein
what is the spinal branch? where is the spinal branch located?
the spinal branch “branches” off the dorsal branch into the spinal cord circulation
the spinal branch lies on top of the spinal root ganglion
occurs on every level of SC
with aortic cross clamping, what complications would you expect?
- SC injury (ischemia > neuronal death)
- ischemia to the lower extremities
- ischemic organ damage (ex. kidney injury)
about how many radicular arteries feed the anterior spinal artery in the neck? thorax? lumbar region?
2-3 in the neck
2-3 in the thorax
1-3 in the lumbar region
what is the Great Radicular Artery (GRA)?
- this is the “feed artery” that supplies blood to the lower 2/3 of the spinal cord
- this structure is AKA Artery of Adamkiewicz
- the GRA typically enters on the left side of spinal cord d/t the aorta also being on the left side
localize the great radicular artery
most approximate location: T10
range: T9-T12 (in the vast majority of people)
extreme range: T5-L5
what are the implications of cross clamping above or below the GRA?
cross clamping below GRA:
* not an issue; no obstruction to flow
cross clamping above GRA:
* possible lower extremity paralysis
* GRA feeds into anterior spinal artery which is the most important artery in the anterior spinal cord
* Ant. SA is closest to gray matter in spinal cord, where many motor neurons are located > possible ischemia > possible paralysis
the lower the GRA is in the SC, the safer it is to do an aneurysm repair
if imaging can be done prior to AAA repair, MRI can be done to localize
cerebral perfusion pressure (CPP) = ?
MAP - ICP
“normal 50-150 mmHg” per schmidt