Acrania


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Related to Acrania: exencephaly

acrania

[ā′krān·ē·ə]
(medicine)
Partial or complete absence of the cranium at birth.

Acrania

[ā′krān·ē·ə]
(zoology)
A group of lower chordates with no cranium, jaws, vertebrae, or paired appendages; includes the Tunicata and Cephalochordata.

Acrania

 

a subphylum of lower chordate animals, as opposed to the subphylum of Craniata, or Vertebrata. Acrania have the following characteristics: the head section of the body is not separate; there is no skull (hence the name); the whole body is segmented, including some internal organs, the excretory system, and the sexual glands; the sensory organs are primitive (there are only sensory cells, lying in the skin and along the neural tube); and there is no heart, only a pulsating ventral blood vessel. There are two families. The family Branchiostomatidae includes 19 species, of which the best-known is the lancelet. The family Amphioxididae comprises three species. These three species are small (up to 1 cm) and live at great depths in the equatorial zone of the oceans.

References in periodicals archive ?
Congenital cranial vault defects refer to conditions with similarly dismal prognoses, including exencephaly, anencephaly, acalvaria, and acrania [5].
Acrania is reserved for cases where the entire neurocranium (including the skull and skull base) is absent with complete but abnormal development of brain tissue.
Exencephaly is a congenital malformation along a spectrum that includes acrania and anencephaly (acrania-exencephaly-anencephaly sequence).
After completing his National Service, Peter started out in racing with Billy Larkin at Gatwick, proceeding, via Jack Holt (for both of whom he rode winners), to Ryan Price, thence to Peter Thrale and Don Butchers and ultimately to Guy Harwood at Pulborough, for whom he was head man between 1966-75, in the years at Coombelands that featured Young Generation, Acrania, King Kathy, Jan Ekels and Call Of The Wild.
El 4 de octubre de 2002 se practica un segundo control ecografico, el cual coincide con la semana 24 de gestacion a partir de la FUM, y en el estudio se encuentran signos sugestivos de gestacion de 20 semanas, actividad cardiaca presente, liquido amniotico abundante y posible defecto de boveda craneal, compatible con acrania a ser descartado.
Este caso, diagnosticado ecograficamente como una acrania y posteriormente como una anencefalia, resulto ser, al examen anatomico, un encefalocele.
En este articulo se describe el caso de una gestante procedente del medio rural bajo riesgo de contaminacion quimica, con control clinico desde la onceava semana de gestacion, cuyo producto fue diagnosticado como portador de acrania a la vigesima semana y como portador de anencefalia a la vigesimo segunda semana de gestacion.
In this article we describe the case of a pregnant woman from rural origin under risk of chemical contamination, who had clinical control from the eleven week of pregnancy and whose product was diagnosed during the twentieth week as carrier of acrania and also as carrier of anencephaly during the twenty-second week of gestation.