This site is targeted at medical and radiology professionals, contains user contributed content and material that may be confusing to a lay audience. Use of this site implies acceptance of our Terms of Use.

Banana sign

The banana sign is one of the many notable fruit inspired signs.

It is seen on axial imaging through the posterior fossa of fetus and is associated with the Chiari II malformation. It describes the way the cerebellum is wrapped tightly around the brain stem as a result of spinal cord tethering and downward migration of posterior fossa content. The cisterna magna gets obliterated and the shape of the cerebellum has the appearance of a banana. The sign persists into the second and third trimesters.

The banana sign is also seen in the majority of fetuses with spina bifida, but disappears >24 weeks. There is very frequently concurrent hydrocephalus.

Associated signs

The same condition also gives rise to the lemon sign.

Related articles

Inspired signs

Updating… Please wait.


Error Unable to process the form. Check for errors and try again.

Alert_accept Thank you for updating your details.