UPDATE 3-armed Baby's Surgery Successful

from WDIV Detroit TV 4

A 2-month-old Chinese boy was recovering Tuesday after surgery to remove an unusually well-formed third arm. Neither of the boy's two left arms was fully functional, but surgeons decided to remove the one growing closer to his chest after tests showed it was less developed.

The baby will require long-term physical therapy to gain function in his remaining hand, which has no palm and flexes in either direction.

Doctors do not know what causes such additional limbs, although many speculate they start out as limbs of a conjoined twin that never developed. He ruled out environmental factors such as birth defect-causing pollution, saying that couldn't fully explain similar cases elsewhere. No reliable figures exist on the frequency of such cases, partly because many fetuses with more than four limbs are aborted or miscarried. In most cases where the fetus survives, it's clear which limb is less developed and should be amputated. This case was especially rare because both left arms were almost equally developed.