banana sign

banana sign

the abnormal curvature of the cerebellum noted on ultrasound imaging in a fetus with Arnold-Chiari malformation.
An ultrasonographic finding seen when a major neural tube defect accompanies Arnold-Chiari malformation, spina bifida and other neural tube defects
Appearance Cerebellar tonsils and midbrain structures herniate into the foramen magnum, causing ventriculomegaly 2º to compression of the outflow from the 3rd and 4th ventricles; the ‘banana’ corresponds to the compressed cerebral hemisphere

banana sign

Imaging An ultrasonographic finding seen when a major neural tube defect accompanies Arnold-Chiari malformation Appearance Cerebellar tonsils and midbrain structures herniate into the foramen magnum, causing ventriculomegaly 2º to compression of the outflow from the 3rd and 4th ventricles; the 'banana' corresponds to the compressed cerebral hemisphere.

ba·na·na sign

(bă-nan'ă sīn)
The abnormal curvature of the cerebellum noted on ultrasound imaging in a fetus with Arnold-Chiari malformation
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References in periodicals archive ?
8] Cerebellar abnormalities are present in 95% of fetuses with open spina bifida scanned before 24 weeks (either the banana sign, where the cerebellum is curved and elongated not the usual rounded dumb-bell appearance- or absence of the cerebellum).
Evaluation of the lemon and banana signs in one hundred thirty fetuses with open spina bifida.