Mumbai, Last week, the co-joined twins born at a hospital have posed a medical challenge for doctors, and a special committee of four senior practitioners will take a call tomorrow on the surgery to separate them. On last Wednesday, the twins, who have a very complex internal architecture, were born at Sion Hospital. According to doctors, the mother and the twins are in good health. Shahin Khan 26 gave birth to the twins, who have fully developed heads, are joined from above the chest. They have three arms, with the third one protruding from the back. The twins were diagnosed in an ultrasonography test conducted at the hospital during the woman's 32nd week of pregnancy. Internally, the twins have one liver and a heart with two aortas. The right one has two lungs and the left one has one underdeveloped lung. The structure of urinary bladder is not clear. The conjoined twins are now under the care of paediatric surgeon Paras Kothari, who is examining if they can be separated without risking their lives. A special committee consisting of four senior medical practitioners will take a call on their separation surgery tomorrow, Dr Kothari said.