I have an injury on my foot and I noticed that I can feel my my blood pulsating through that part of my foot. I think I have noticed this on other parts of my body that get hurt as well like my arms and hands. I’m sure someone else has experienced this before? Is this because there is less skin between blood veins and the outside world? Thanks!
Two reasons: one, there’s always a pulse in your foot, you’re probably just not very aware of your foot until it’s injured. And two, when an area is injured, the blood vessels in the area dilate (open up) to allow more blood to flow into the area. A dilated blood vessel is easier to feel than a regular one, so you notice it more when you have an injury.
I believe that this is because the injury will cause swelling around it, as blood and lymph fluids all move into the damaged areas through torn blood vessels. As your injury swells, the ‘normal’ pressure felt by the neurons that are affected by touch goes over your normal threshold values. So, the normal variations in internal fluid pressures that your brain automatically edits out are all coming through as new, important signals. For some people that throbbing you mention, in time with your pulse, isn’t even painful. Just something they can’t ignore.
Ah, that makes sense. Thanks for the quick answers!