AskDefine | Define conjoined

Dictionary Definition

conjoined adj : consisting of two or more associated entities; "the interplay of these conjoined yet opposed factors"; "social order and prosperity, the conjoint aims of government"- J.K.Fairbank [syn: conjoint]

User Contributed Dictionary



  1. Joined together, as with conjoined twins, or in matrimony.
    1600 If either of you know any inward impediment, why you should not be conjoined, I charge you, on your souls, to utter it. — Shakespeare, Much Ado About Nothing, Act 4, Scene 1.

Usage notes

Conjoint is often used, but conjoined is the preferred usage.


  1. past of conjoin

Extensive Definition

Conjoined twins are whose bodies are joined in utero. It is a rare phenomenon; it is estimated to range from 1 in 50,000 births to 1 in 200,000 births, with a somewhat higher incidence in Southwest Asia and Africa. Approximately half are stillborn, and a smaller fraction of pairs born alive have abnormalities incompatible with life. The overall survival rate for conjoined twins is approximately 25%.
About 70% to 75% of conjoined twin pairs are female.
Two contradicting theories exist to explain the origins of conjoined twins. The older and most generally accepted theory is fission, in which the fertilized egg splits partially. The second theory is fusion, in which a fertilized egg completely separates, but stem cells (which search for similar cells) find like-stem cells on the other twin and fuse the twins together.
Perhaps the most famous pair of conjoined twins was Chang and Eng Bunker (18111874), Chinese brothers born in Siam, now Thailand. They traveled with P.T. Barnum's circus for many years and were billed as the Siamese Twins; due to their fame and the rarity of the condition, the term came to be used as a synonym for conjoined twins, although in recent years the term has fallen out of favor and is considered a pejorative term. Chang and Eng were joined by a band of flesh, cartilage, and their fused livers at the torso. In modern times, they could have been easily separated.

Conjoined twins in history

The earliest known documented case of conjoined twins dates from the year 945, when a pair of conjoined twin brothers from Armenia were brought to Constantinople for medical evaluation. It was here that they were determined to be acts of God and the birth of conjoined twins was considered a proof that the male's sexual prowess was truly twice that of the average man. However, the Moche culture of ancient Peru depicted conjoined twins in their ceramics dating back to AD 300. The English twin sisters Mary and Eliza Chulkhurst, who were conjoined at the back (pygopagus), lived from 1100 to 1134 and were perhaps the best-known early example of conjoined twins. Other early conjoined twins to attain notice were the "Scottish brothers", allegedly of the dicephalus type, essentially two heads sharing the same body (14601488, although the dates vary); the pygopagus Helen and Judith of Szőny, Hungary (17011723), who enjoyed a brief career in music before being sent to live in a convent; and Rita and Cristina of Parodi of Sardinia, born in 1829. Rita and Cristina were dicephalus tetrabrachius (one body with four arms) twins and although they died at only eight months of age, they gained much attention as a curiosity when their parents exhibited them in Paris.

Types of conjoined twins

There are several different types of conjoined twins:
  • Diplopagus: Conjoined twins joined equally with near complete body, only sharing a few organs.
  • Heteropagus: Conjoined twins joined unequally usually resulting in a parasitic twin.
  • Thoracopagus: Bodies fused in the thorax. The heart is always involved in these cases; when the heart is shared, prospects for a long life, either with or without separation surgery, are poor (35-40% of cases).
  • Omphalopagus: Joined at the lower chest. The heart is not involved in these cases but the twins often share a liver, digestive system, diaphragm and other organs (34% of cases).
  • Pygopagus (iliopagus): Joined, usually back to back, to the buttocks (19% of conjoined twins).
  • Cephalopagus: Heads fused, bodies separated. These twins generally cannot survive due to severe malformations of the brain. Also known as janiceps (after the two-faced god Janus) or syncephalus.
    • Cephalothoracopagus: Bodies fused in the head and thorax. In this type of twins, there are two faces facing in opposite directions, or sometimes a single face and an enlarged skull. These twins also generally cannot survive. (Also known as epholothoracopagus or craniothoracopagus.)
  • Craniopagus: Skulls fused, but bodies separate (2%).
  • Dicephalus: Two heads, one body with two legs and two, three, or four arms (dibrachius, tribrachius or tetrabrachius, respectively.) Abigail and Brittany Hensel, 18-year-old conjoined twins from the United States, are of the dicephalus tribrachius type, with their third arm having been removed while they were very young.
  • Ischiopagus: Anterior union of the lower half of the body, with spines conjoined at a 180° angle (6% of cases). Or with the spines separate but both the pelvises forming a single big ring which includes two sacrums and two pubic symphyses.
  • Ischio-omphalopagus:The Twins are conjoined with spines in a Y-shape. They have four arms and usually two or three legs. These cases can be challenging because the twins often share reproductive and excretory systems.
  • Parapagus: lateral union of the lower half extending variable distances upward, with the heart sometimes involved (5% of cases).
  • Diprosopus: One head, with two faces side by side. A malformation of a single embryo, not true conjoined twinning.
In some cases, parts of the brain have been known to be shared between conjoined twins joined at the head.


Surgery to separate conjoined twins may range from relatively simple to extremely complex, depending on the point of attachment and the internal parts that are shared. Most cases of separation are extremely risky and life-threatening. In many cases, the surgery results in the death of one or both of the twins, particularly if they are joined at the head. This makes the ethics of surgical separation, where the twins can survive if not separated, contentious. Dreger found the quality of life of twins who remain conjoined to be higher than is commonly supposed. Lori and George Schappell are a good example.


See also

External links

conjoined in Czech: Siamská dvojčata
conjoined in German: Siamesischer Zwilling
conjoined in Spanish: Siameses
conjoined in French: Frères siamois
conjoined in Korean: 결합 쌍둥이
conjoined in Indonesian: Kembar siam
conjoined in Italian: Gemelli siamesi
conjoined in Hebrew: תאומים סיאמיים
conjoined in Dutch: Siamese tweeling
conjoined in Japanese: 結合双生児
conjoined in Norwegian: Siamesiske tvillinger
conjoined in Polish: Zroślak
conjoined in Russian: Сиамские близнецы
conjoined in Simple English: Conjoined twins
conjoined in Slovenian: Zraščena dvojčka
conjoined in Finnish: Siamilaiset kaksoset
conjoined in Swedish: Siamesiska tvillingar
conjoined in Thai: แฝดติดกัน
conjoined in Chinese: 連體嬰
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