Most people who've had a limb removed report that it sometimes feels as if their amputated limb is still there. This painless phenomenon, known as phantom limb sensation, can also occur in people who were born without limbs. Phantom limb sensations may include feelings of coldness, warmth or itchiness or tingling " but should not be confused with phantom pain. Similarly, pain from the remaining stump of an amputated limb is not phantom pain.
Characteristics of phantom pain include (Mayo Clinic): .
• Onset within the first few days of amputation.
• Tendency to come and go rather than be constant.
• Usually affects the part of the limb farthest from the body, such as the foot of an amputated leg.
• May be described as shooting, stabbing, boring, squeezing, throbbing or burning.
• Sometimes feels as if the phantom part is forced into an uncomfortable position.
• May be triggered by weather changes, pressure on the remaining part of the limb or emotional stress.
Causes.
The exact cause of phantom pain is unclear, but it appears to originate in the spinal cord and brain. During imaging scans " such as magnetic resonance imaging (MRI) or positron emission tomography (PET) " portions of the brain that had been neurologically connected to the nerves of the amputated limb show activity when the person feels phantom pain (Mayo Clinic). Many experts believe phantom pain may be at least partially explained as a response to mixed signals from the brain. After an amputation, areas of the spinal cord and brain lose input from the missing limb and adjust to this detachment in unpredictable ways. The result can trigger the body's most basic message that something is not right: pain (Mayo Clinic).
Studies also show that, after an amputation, the brain may remap that part of the body's sensory circuitry to another part of the body.