Conjoined twins, popularly referred to as Siamese twins, are twins joined in utero. It is a very rare phenomenon, estimated to occur in anywhere between one in 49,000 births to one in 189,000 births, with a somewhat higher incidence in Southwest Asia and Africa. Approximately half are stillborn, and an additional one-third die within 24 hours. Most live births are female, with a ratio of 3:1.
Ladan and Laleh Bijani were Iranian conjoined twin sisters. They were joined at the head and died soon after their complicated surgical separation.
Craniopagus parasiticus is an extremely rare type of parasitic twinning occurring in about 4 to 6 of 10,000,000 births. In craniopagus parasiticus, a parasitic twin head with an undeveloped body is attached to the head of a developed twin. Fewer than a dozen cases of this type of conjoined twin have been documented in literature.
Keith Goh is a neurosurgeon from Singapore. Goh is known for his operations in separating conjoined twins with two known successful cases and a failed attempt in separating Ladan and Laleh Bijani.
Abigail Loraine Hensel and Brittany Lee Hensel are American conjoined twins. They are dicephalic parapagus twins, and are highly symmetric for conjoined twins. Each has a heart, stomach, spine, pair of lungs, and spinal cord. Each twin controls one arm and one leg. When they were infants, learning to crawl, walk, and clap required cooperation. They can eat and write separately and simultaneously. Activities such as running, swimming, hair-brushing, playing piano or volleyball, riding a bicycle, or driving a car require coordination.
Sirenomelia, also called mermaid syndrome, is a rare congenital deformity in which the legs are fused together, giving the appearance of a mermaid's tail, hence the nickname.
Ischiopagi comes from the Greek word ischio- meaning hip (ilium) and -pagus meaning fixed or united. It is the medical term used for conjoined twins who are united at the pelvis. The twins are classically joined with the vertebral axis at 180°. The conjoined twins usually have four arms; two, three or four legs; and typically one external genitalia and anus.
Clarence and Carl Aguirre are former conjoined twins born in Manila. They were conjoined at the top of the head and shared 8 centimetres (3.1 in) of brain. More than 1–2 centimetres (0.4–0.8 in) will affect brain functionality in one or both of twins. Without separation, they were expected to live around 6–8 months.
Kendra Deene Herrin and Maliyah Mae Herrin are former conjoined twins. They were separated in August 2006. They were the first set of conjoined twins to be separated to share a kidney. Kendra retained their shared kidney following the separation surgery, while Maliyah Herrin underwent dialysis until she was transplanted with a kidney donated by her mother in April 2007.
Chained for Life is a 1952 exploitation film featuring the famous conjoined ("Siamese") Hilton Twins, Daisy and Violet. It features several vaudeville acts, including juggler Whitey Roberts, a man doing bicycle stunts, and a man, Tony Lovello, who plays the William Tell Overture and "Hungarian Dance No. 5" at breakneck speed on an accordion.
Krista and Tatiana Hogan are Canadians who are conjoined craniopagus twins. They are joined at the head and share a skull and a brain. They were born in Vancouver, British Columbia, and are the only unseparated conjoined twins of that type currently alive in Canada. They live with their mother, Felicia Simms, in Vernon, British Columbia, have two sisters and a brother and often travel to Vancouver for care at BC Children's Hospital and Sunny Hill Health Centre for Children.
Lakshmi Tatma is an Indian girl born in 2005 in a village in Araria district, Bihar, with four arms and four legs. She was actually one of a pair of ischiopagus conjoined twins, one of which was headless because its head had atrophied and chest had not fully developed in the womb, causing the appearance of one child with four arms and four legs. She has undergone surgery to remove these extra limbs.
Viet Nguyen and Duc Nguyen were a pair of Vietnamese conjoined twins surgically separated in 1988. Viet died in 2007 of natural causes.
Wirginia June Maixner is an Australian neurosurgeon and the director of neurosurgery at the Royal Children's Hospital in Melbourne, Australia. She is known for having performed the first auditory brainstem implant on a child in Australia in 2007, and later having separated the conjoined twins, Trishna and Krishna in 2009.
Craniopagus twins are conjoined twins who are fused at the cranium. The union may occur on any portion of the cranium, but does not primarily involve either the face or the foramen magnum; the two brains are usually separate, but they may share some brain tissue. Conjoined twins are genetically identical and always share the same sex. The thorax and abdomen are separate and each twin has their own umbilicus and umbilical cord.
Anthony David Holmes AO is a plastic and reconstructive surgeon. His most high-profile surgery was in 2009 when he worked with a large team of experts to separate the Bangladeshi conjoined twins Trishna and Krishna.
Muhimbili National Hospital is a 1500-bed public teaching hospital located in Upanga West ward of Ilala District in Dar es Salaam Region of Tanzania. It is the national referral hospital as well as academic and research facility for the Muhimbili University of Health and Allied Sciences. It offers speciality care across the spectrum of clinical medicine. About 40% of its beds are for private patients. The hospital employs around 2705 workers including 328 doctors and 946 nurses.
James Tait Goodrich was an American neurosurgeon. He was the director of the Division of Pediatric Neurosurgery at Montefiore Health System and Professor of Clinical Neurological Surgery, Pediatrics, Plastic and Reconstructive Surgery at the Albert Einstein College of Medicine, and gained worldwide recognition for performing multiple successful separations of conjoined twins. He assisted in two craniopagus separations with Dr. Alferayan A in Riyadh, Saudi Arabia, with the first one done May 5, 2014 and the second one done February 14, 2016. Both pairs were successfully separated and are doing well.
Dr Noor ul Owase Jeelani BMed.Sci (Hons), BMBS, MRCS, MBA, MPhil, FRCS (NeuroSurg.) is a Kashmiri-British neurosurgeon and academic. He is a Consultant Paediatric Neurosurgeon at Great Ormond Street Hospital for Children (GOSH) and was the Head of the Department of Neurosurgery from 2012 until 2018. He is an Honorary Associate Professor at the Institute of Child Health, University College London. He leads the FaceValue research group in Craniofacial Morphometrics, device design, and clinical outcomes.
András Csókay, is a Hungarian neurosurgeon with international recognition in the field of neurosurgery for his development of a technique to enhance microsurgical precision in the vascular tunnel and for the separation of a pair of Bangladeshi (Islam) Craniopagus Twins.