Mononeuropathy is a type of damage to nerves outside the brain and spinal cord (peripheral neuropathy). Mononeuropathy is most often caused by injury, although body-wide (systemic) disorders may cause isolated nerve damage. Long-term pressure on a nerve due to swelling or injury can result in mononeuropathy. The covering of the nerve (myelin sheath) or part of the nerve cell (the axon) may be damaged. This damage slows or prevents signals from traveling through the damaged nerves. Mononeuropathy may involve any part of the body.