[betty boop]

A missing limb that itches or feels pain should, under normal circumstances, convince the reasonable person that those sensations occur in the mind.

You would think so, Dataman! Thanks for the great observation.

[marron]

The limb is gone, but the nerve that serviced it is still there. The nerve ending where it was cut is still coiled in the end of the cut limb. The nerve ending may be transmitting, or the nerve itself may have a signal induced onto it by surrounding activity that the brain decodes as coming from the limb that isn't there anymore.