Özet:

Chiari malformations divided into 3 groups. Chiari type I malformation is caudal protrusion of cerebellar tonsils. Type II malformation is the most common and associate with meningomyelocele. Type III is a high cervical meningoencephalocele and uncommon. Spina bifida, has classified into open and closed forms as skin covered spine lesions. Cranial signs are not accompaniment on closed type. Open type usually diagnosed on prenatal period. Typical findings are ventriculomegaly, lemon sign (bifrontal indentation), banana sign (Chiari II malformation), obliteration of cisterna magna and small BPD and body measurements according to gestation age. Occipital horns are higher than 10 mm in ventriculomegaly. Choroid plexus are small and looking like tear. Limon sign defines biconcave frontal bones as looking like a lemon. Banana sign and obliteration of cisterna magna resulted cause of hypoplasia of posterior fossa. Compression of cerebellum causing abnormal localization, although cerebellar tonsils and vermis herniated to foramen magnum. Hemispheres are wrapping brain stem and looking like ‘‘C\'\' (banana sign). Spinal longitudinal sonogram reveals open spine and skin defect, although dilatation on spine canal and increased interpedincular distance.

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