Topic Overview Back to top What is spina bifida? Spina bifida is
a type of birth defect called a neural tube defect. It occurs
when the bones of the spine (vertebrae) don't form properly
around part of the baby's spinal cord. Spina bifida can be mild
or severe. - The mild form is the most common. It usually
doesn't cause problems or need treatment. You can't see the
defect, but some people may have a dimple, birthmark, or hairy
patch on their back. Most people with this form don't know they
have it until they get a back X-ray for another reason. - A rare
and more severe form is meningocele (say "muh-NIN-juh-seel"). In
this form, fluid leaks out of the spine and pushes against the
skin. You may see a bulge in the skin. In many cases, there are
no other symptoms. - The most rare and severe form is
myelomeningocele (say "my-uh-loh-muh-NIN-juh-seel"). It's what
most people mean when they say "spina bifida." Part of the
spinal nerves push out of the spinal canal, and the nerves are
often damaged. You may see a bul