Common Causes of Numbness Nerve Compression Any position or disease process that blocks nerve signals can lead to numbness. If you’ve ever sat on your foot for too long and stood up only to find it feels completely “asleep,” you’ve likely been compressing nerves in your leg, ankle or foot. Those uncomfortable pins and needles are usually the sign of nerve function re-establishing itself. Herniated or degenerating discs in the spine or narrowing of the spinal column may press on spinal nerves, causing numbness or abnormal sensations in any area of the body served by those nerves (often in the legs). Any mass, enlarged vessel, scar tissue or swelling from infection or injury may also cause local compression of nerves. One common example is carpal tunnel syndrome, which occurs when the median nerve in the wrist becomes compressed by surrounding tissue, causing numbness and tingling in the hand.