What phantom limbs are

Nearly everyone who undergoes the sudden loss of a limb will continue to feel the presence of and experience sensations in the missing limb for at least some time after the loss. This "phantom limb" phenomenon has been known for centuries, but remains poorly understood. Most work on phantom limb phenomena focuses on the phantom sensations, especially pain, that seem to emanate from the missing limb. This work tends to focus on the role of the body image in maintaining the sense of the phantom. A minority of work in the field distinguishes the body image from body schema, and offers an important corrective to the literature by outlining the unique contribution of the latter to generating and maintaining phantom limb phenomena. Here I review this literature, and motivate a further distinction between a motor body schema and a somatosensory body schema, which allows me to develop a novel hypothesis about the specific contributions of each to the experience of a phantom limb.