Boy with three arms to undergo surgery on Tuesday

"The biggest difficulty here is from the risk of damage to nerves and blood vessels in the shoulder," said Chen. He said the surgery is expected to last from three to five hours.

Photo: Boy with three arms to undergo surgery on Tuesday

Still, Chen said the boy, identified only as "Jie-jie," will require long-term physical therapy because the hand on the arm that will remain does not currently appear to function.

The boy was also born with just one kidney and may have problems that could lead to curvature of the spine. Chen said it was not clear how those problems might be linked to the third arm, the AP reports.

The boy's small size has made it difficult to perform certain tests that would help doctors prepare a plan for surgery, Chen said.

Other children have been reported born in China with additional arms or legs, but in all those cases it was clear which limb was more developed.

Chen's hospital is one of China's most experienced in dealing with unusual birth defects, including separating conjoined twins.