>>73487
cyanosis takes place in the extremities and occurs when there’s a factor causing decreased levels of blood oxygen and low blood pressure. there are a lot of things that can cause this, anemia and low body weight being one of them, but also, benzodiazepines are known to be a direct cause of low blood pressure, aka hypotension (not hypertension), among other things

benzodiazepines and other relaxants are fatal because they can cause complete respiratory failure. the respiratory failure is the condition, the actual cause of the fatality is hypoxia (brain) or cardiac arrest and likely a combination of the two are present

now yes, cyanosis can cause a bluish tint in extremities because blood that has low oxygen is much darker. you can see an example of this when you look at oxygenated blood from arteries compared to venous blood traveling through the circulatory system. that being said, the reason this color contrast is apparent in extremities for people with cyanosis is because their circulatory system is still working and there’s still… a contrast to be had. might sound crazy but when you die, your heart stops pumping blood and your circulatory system is no longer circulatory. so what happens now?

blood is a liquid, it has mass, and all things with mass are affected by gravity. that blood doesn’t just stay suspended in your veins in the same place upon death unless there’s something constricting it. squeeze your finger at the first knuckle until it turns blue. it’s cold and purple but when you let go, it returns to normal. but say that you died with something preventing that blood to flow out again, it’s going to coagulate and stay in place and that’s when you get dark discoloration and livor mortis in areas that are affected by gravity but still have discoloration. you see that often in autoerotic asphyxiation or ligature marks on the hands and necks of murder victims

that blood is going to blood. it’s going to pool and ciara would have been pale with little to no discoloration apparent unless she was moved. it certainly wouldn’t have been all over.

this is a very draconian explanation of a very complicated process and it’s hard to do justice so hopefully pictures help more than words

sources:
J. Dix- Color Atlas of Forensic Pathology, v.2000
Wikipedia- Arterial Blood
Overdosed woman- Some gore site probably