Watershed areas

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

panmit

Full Member
7+ Year Member
Joined
May 14, 2014
Messages
260
Reaction score
131
Why are watershed areas, splenic flexure and rectosigmoid areas prone to ischemia when they have dual blood supplies (i.e. SMA and IMA for splenic flexure). Doesn't it seem counter intuitive?

Members don't see this ad.
 
Watershed areas are at the most distal tips of arteries, like this:
===(artery)===> splenic flexure <===(artery)===
And this means perfusion pressure is kind of low to them (because they're at the most distal tips), so if there's a systemic drop in BP (shock) they won't get perfused enough = ischemia

and yes it seems counter intuitive, quality over quantity i guess
 
Watershed areas are at the most distal tips of arteries, like this:
===(artery)===> splenic flexure <===(artery)===
And this means perfusion pressure is kind of low to them (because they're at the most distal tips), so if there's a systemic drop in BP (shock) they won't get perfused enough = ischemia

and yes it seems counter intuitive, quality over quantity i guess
Ahh kk. I see. So in hypoperfusion they are prone to ischemia, however, let’s say in a rare occlusive event anastomoses will redirect blood flow and still perfuse the area. So during thrombotic events it’s good, and events like shock watershed sucks.
 
Actually the splenic flexure (although its supplied by branches of the IMA and SMA) will become ischemic even if just one supply fails (because the other supply doesn't perfuse strong enough).

Idk if this is the case for other watershed areas
 
Members don't see this ad :)
Actually the splenic flexure (although its supplied by branches of the IMA and SMA) will become ischemic even if just one supply fails (because the other supply doesn't perfuse strong enough).

Idk if this is the case for other watershed areas
Okay cool thanks bro. Yeah seems counter intuitive. Like first aid and other resources stress the importance of dual blood supply and in the end it doesn’t matter - it will still be ischemic
 
Okay cool thanks bro. Yeah seems counter intuitive. Like first aid and other resources stress the importance of dual blood supply and in the end it doesn’t matter - it will still be ischemic
There are other areas that resist infarction more than others because of their dual blood supply, e.g the lungs (bronchial a + pulmonary a)

also some parts of the colon (thanks to the marginal artery and all the arcades)
 
Top