About Spina Bifida

What is spina bifida?

Spina bifida is a neural tube defect that frequently occurs in families.  Spina bifida occurs because of an abnormality of the development of the spinal cord that occurs in the first trimester of pregnancy. Within the first 4 weeks after a fetus is conceived, the backbone and membranes that cover and protect the spinal cord and spine does not form and close properly. This can result in an opening anywhere along the spine and may cause damage to the spinal cord and nerves. The defect may be associated with a protrusion of the membrane covering the spinal cord (meninges) alone, called a meningocele, or with some neural elements, called a meningomyelocele. Or the defect may not be noticed until later in life.

Spina bifida can cause physical and mental disabilities ranging from mild to severe, depending on the size and location of the opening in the spine, and whether the spinal cord and nerves are affected.1

The three most common types of spina bifida are as follows:

Myelomeningocele, in which a sac of fluid containing part of the spinal cord and nerves comes through an opening in the infant’s back, causing nerve damage. Also called “open spina bifida,” this condition causes moderate to severe disabilities, such as problems going to the bathroom, loss of feeling in the legs or feet, and paralysis in the legs.

Meningocele, in which a sac of fluid without the spinal cord comes through an opening in the infant’s back. This type of spina bifida can cause minor disabilities, but there is usually little or no nerve damage.

Spina Bifida Occulta, the mildest type of spina bifida, in which there is a small gap in the spine but no opening or sac on the back. Some infants have a dimple, hairy patch, dark spot, or swelling at the affected place on the back, but the spinal cord and the nerves usually are not damaged. This type of spina bifida usually does not cause any disabilities. Often, spina bifida occulta is not discovered until late childhood or adulthood and sometimes not at all. This is why it is sometimes called “hidden” spina bifida.


  1. Centers for Disease Control and Prevention. (2011). Spina bifida: Facts. Retrieved March 30, 2012, from https://www.cdc.gov/spina-bifida/about
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