Moonlight,
Right at the natural place to tie your wrists is where the nerves running to your hands are routed. Palm up – they run on the side of the wrist when you’re looking at it. Turn your hand palm down and make a hard fist. On the opposite side of your arm from your wrist bone you should see a muscle bunch up. Below this muscle (toward your elbow) is where your Dom should be tying. Even tied correctly, arms-over- head means that this tie is going to slip up because of the natural shape of the arm. So, to protect yourself you should turn your hands in and grasp the rope so that the weight of the tie is supported on the outside of your wrist. Another option is to use cuffs for overhead to spread the load over a larger surface area. Nerve damage in this area typically leads to “wrist drop” or the inability to lift your hand in an upward motion. Another side effect can be lost of strength in your thumb causing lack of grip.
To determine if you are experiencing nerve compression or lack of circulation your Dom should do a capillary refill test.
http://health.allrefer.com/health/capillary-nail-refill-test.html Keep in mind that you may still be experiencing nerve compression if the tie is not in the correct place.
Arms-over –head also presents some challenges in the shoulder area. The space between your shoulder and collar bones is very small. Lifting your arms over your head can cause what’s called an impingement injury. The nerves and blood vessels heading down to your arms are routed through this small space and can be pinched between these bones. It’s equivalent to turning your steering wheel all the way over one way until it slams into the stops and you hold it there while the power steering pump squeals. The good thing about this area is it’s typically a sharp pain and not something that sneaks up on you like wrist drop.
The leg numbness could be caused by being in the same position too long. As Sebastian suggests practice could help this. A lot depends on the exact position you’re in and if your legs are tied. I personally use the two finder rule for compressing ties, I use cuffs over nerve areas if there will be struggling or the risk of the tie slipping, and I limit restricted movement to 15-20 minutes.
