Acephaly (medicine)
Encyclopedia
Acephaly is a type of cephalic disorder
. It literally means absence of the head. It is a much rarer condition than anencephaly
. The acephalic fetus is a parasitic twin
attached to an otherwise intact fetus. The acephalic fetus has a body but lacks a head and heart; the fetus's neck is attached to the normal twin. The blood circulation of the acephalic fetus is provided by the heart
of the twin. The acephalic fetus cannot exist independently of the fetus to which it is attached. Similarly, acardiac fetuses lack everything from the heart upwards, including head and arms, and behave similarly to acephalic fetuses.
Cephalic disorder
Cephalic disorders are congenital conditions that stem from damage to, or abnormal development of, the budding nervous system...
. It literally means absence of the head. It is a much rarer condition than anencephaly
Anencephaly
Anencephaly is a cephalic disorder that results from a neural tube defect that occurs when the cephalic end of the neural tube fails to close, usually between the 23rd and 26th day of pregnancy, resulting in the absence of a major portion of the brain, skull, and scalp...
. The acephalic fetus is a parasitic twin
Parasitic twin
A parasitic twin is the result of the processes that produce vanishing twins and conjoined twins, and may represent a continuum between the two...
attached to an otherwise intact fetus. The acephalic fetus has a body but lacks a head and heart; the fetus's neck is attached to the normal twin. The blood circulation of the acephalic fetus is provided by the heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
of the twin. The acephalic fetus cannot exist independently of the fetus to which it is attached. Similarly, acardiac fetuses lack everything from the heart upwards, including head and arms, and behave similarly to acephalic fetuses.