Why does a bruise turn black and blue?
411422
Bruises, also known as contusions or ecchymoses, are what develop when your skin gets smashed for some reason but not broken. The soft tissues are damaged, the little vein or capillaries under your skin rupture and the blood puddles up under your skin. That's why a new bruise is red. It's all that nice red blood pooling up.\n\nEventually your body goes to work and starts metabolizing the spilled blood. After a couple of days, the bruise will look black or blue. By the sixth day, it goes all greenish on you, and then a few days later, it will turn sort of yellowish brown. It all has to do with the chemical changes involved in metabolizing that blood and getting things fixed up in there. \n\nAnd the reason that older people seem to bruise more easily is that their veins and capillaries and so forth grow more delicate with age and are more easily ruptured.  http://www.azcentral.com/news/columns/articles/0105clay05.html
167734
Yes, it could be cyanosis.  If there is lack of blood circulating to the hands and fingers, then your tissues starts to turn a dusky blue color.  If there are problems of the back like you stated, it is possible that some of the vessels are compressed, thereby decreasing the blood flow.  Decreased blood flow can also cause headaches.  If your brain isn't getting enough oxygen, it goes into a state of ischemia (no oxygen) and that pain results.  It should be checked out by a neurologist or start with a pain specialist.  Good Luck!!
760471
See a doctor, black stuff could be stale blood. Stale blood can be a good media for bacteria to breed.
832270
there are a number of reasons\nperhaps your blood vessels are close to the surface of you skin so that when you bump into something you bruise\nanother reason is that you are taking a blood thinning medication such as heparin which causes easy bruising\nthirdly you could have leukemia or another blood disease\ncheck with your doctor to find the cause\ngood luck
278481
It could depending on what you have had to eat. If you eat or drink something with blue coloring in it, it can turn blue.
763492
Actually the bump on the head is due to edema or a fluid accumulating in the area that you got hit thats why its a big buldge this fluid contains all kinds of cells neutrophils and macrophages. The bump will cause a break in the continuity of your blood vessles, and you get some blood leaking and slowly itll be engulfed. Since the head as well as most of hte body is rich in blood vessels its not a worry if a few vessles break when getting injured. Slowly the injured tissues (site of the bump) will start being selectively removed and newer tissues will form, this is why you see the different color changes every few days 2-3 days about, from red to blue to green to brown then faint and finally back to normal. Bruising in the head might be more severe though because it doesnt have fascia or fat protecting it under the skin layer, good luck hope this helps you.
775206
Blood is NEVER blue... Your veins are gray, with red blood within, it appears blue.\n\nYour face loses color due to the lack of hemoglobin, which is present in blood.\n\nThree things determine pigment.\n\nKeratin-Yellows\nMelanin-Browns\nHemoglobin-Reds\n\nEveryone has all three of these pigments present in their skin, when a light-skinned person deprives an area of oxygenated bloodflow, the red tint is removed due to the lack of hemoglobin.\n\nHope this helps!
170850
I just spilled something rude on my black leather sofa & it went lighter not darker!\n\nSeriously though, very good question. \n\nIt obviously has something today with absorbency - a pair of blue jeans gets much darker, a blue plastic sheet hardly changes.\n\nAt a guess, I would say the surface tension of the water bonds it to surrounding molecules, creating a smaller surface area, thus reflecting less light.\n\nIt's just a guess, but feel free to spank me with a wet fish if I'm wrong, lol.
461959
It is blue when the blood does not have oxygen in it.  Once blood is drawn though, it hits the oxygen and turns red.
65667
The color of blood is blue.
408242
Could be bruised or even fractured, if its causing you alot of pain, go see a doctor.
974087
Can you see coloration underneath the skin? It could be a hematoma. You need a doctor as soon as you can get there. (A competent one) If it's a clot and is migrating, it can move anywhere in your body, and cause major problems. (People die from simple blood clots every day, so I would recommend you know whether this is one or not)
95485
bruises from when you break blood vessels under the skin. Since you never actually penetrate the skin, the blood simply pools a bit until it clots, leaving your skin the color of de-oxygenated blood. All you can do is wait until the blood disperses.
230583
usually a stain or paint.\nHehehe, just kidding.\nI think it depends on the fluids inside the organ (ie. melanin, bile, urea, amount of blood flow to the organ, etc)\nAre you thinking of one particularily?
441575
Blood is not blue.  They just draw it that way in science books so you can distinguish arteries from veins.  You can take this to the bank.
171236
You might have bruised some nerves as well.  When that happens you will experience the numbness and tingly sensations you discribe.  If you are 100% certain that nothing is broken then all you can do is wait it out.  If you are really concerned, call your doctor for an exray to make sure you didnt get a hairline fracture of any kind.  I had that when I broke my wrist and it took a while for all the feeling to return.  So long as your fingers are not turning blue then you really have no serious concerns at the moment.  If after say a week and you still have no feeling then you really need to see the dr. to make sure no further damage was done.  Good luck.
310376
Why so blue?\nBecause they contain a lot of salt. Your body has a lot of salt in it.  Blood, sweat, tears, lymph... all salty