The joints they described not only allowed them to move their phantom arms in strange ways, but also got in the way of normal movement.
Essentially, they constructed a new body image of their phantom limb.
"The brain truly does change itself," New Scientist quoted Moseley and Brugger as saying.
"The idea that just thinking about movements can change body image is quite surprising," said Henrik Ehrsson, a neuroscientist at the Karolinska Institute in Stockholm, Sweden.
Brugger expects that the findings could be used to help patients with phantom-limb pain.
An amputee might feel as if their phantom hand is always clenching a metal bar, causing pain, but the discovery increases the chance that amputees can learn to get out of such painful positions.
The study has been published in the journal Proceedings of the National Academy of Sciences.
Source-ANI