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DA: 380

Developmental anomaly information

Definition: The calvaria (or calva, or skullcap) is the roof of the skull. It is formed by the following bones: 1-,rontal bone, 2-parietal bones (two), 3-temporal bones (two), 4-Occipital bone In a fetus, the formation of the calvaria involves a process known as intramembranous ossification, although the base of the skull (underlying the brain) develops through endochondral ossification. Acalvaria is a rare malformation usually regarded as a postneurulation defect. It consists of absense of the calvarial bones, dura mater and associated muscles in the presence of a normal skull base and normal facial bones. The condition is frequenctly confused by prenatal ultrasonography with anencephaly or an encephalocele. Whereas the cerebral hemispheres are absent in anencephaly, the cranial contents in acalvaria are generally complete, though some neuropathological abnormality is often present. The presumed pathogenesis of acalvaria is faulty migration of the membranous neurocranium with normal placement of the embryonic ectoderm, resulting in absence of the calvaria but an intact layer of skin over the brain parenchyma. Acrania is a developmental abnormality characterized by a partial or complete absence of calvarium, with complete but abnormal development of brain tissue. Meroacrania refers to absence of the cranium with the exception of the occipital bone. Meroanencephaly is a form of anencephaly with rudimentary brain and cranium.


  • Acrania

Developmental anomaly parent: Absence of skull bones

Topology: Human body > Head and neck > Head > Cranium

System: Human body > musculoskeletal system. > Bones

Developmental anomaly category: Malformation

Case records MDB191

Humpath: 13553

Observed in MDB cases
Observed in combinaisons (MDB)
Observed in malformative diseases (MDB)
Associated genes in profile
Associated genes in malformative diseases
Associated chromosomal diseases
Associated signaling pathways
Associated developmental anomalies

Here is the list of developmental anomalies associated with this developmental anomaly, based on the cases' information :

Last modified: 2009-01-07 15:01:59 by farideh

Created: 2008-06-10 16:30:25 by farideh

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