RIYADH: Yemeni conjoined twins “Yousuf and Yassin” arrived safely with their parents at King Salman Air Base in Riyadh on Wednesday via an air medical evacuation plane from the city of Al-Mukalla. King Salman ordered the speedy transfer of the twins and their parents to the Kingdom for a medical examination, Dr. Abdullah Al-Rabeeah, the general supervisor of the King Salman Humanitarian Aid and Relief Center (KSrelief) and a renowned pediatric surgeon, said. According to the Journal of Neurosurgery, craniopagus twins represent a rare phenomenon where twins, joined at the top or side of the head, share a portion of the skull. Cases of conjoined twins are rare — only one per 200,000 births — as most are female, according to various studies. After their arrival, the twins were transferred to the King Abdullah Specialist Children’s Hospital at the Ministry of National Guard so they could be examined as doctors will consider the possibility of separating them. Mohammed Abdulrahman, the twins’ father, extended his thanks and gratitude to King Salman and Crown Prince Mohammed bin Salman for transporting the twins and examining their condition. He also praised the warm reception his family received and the Kingdom for its generous humanitarian work. Al-Rabeeah also thanked the king, the crown prince, and the coalition forces abroad for their “noble humanitarian initiative that comes in recognition of the difficult conditions facing Yemen,” the Saudi Press Agency reported. This is the 116th case to be examined and assessed by the Saudi National Program for Separating Conjoined Twins since the program started in 1990. Patients from 21 countries have been examined while more than 50 operations have been performed to separate such twins. Cases of conjoined twins usually occur in Central African, South East Asian and Latin American populations due to an increased rate of identical twins; a determining factor in the birth rate of conjoined twins.