DEFINITION
The developmental anomaly of meningothelial elements displaced into the skin and subcutaneous tissue, is referred to as Neural Tube Defect (NTD). It is also commonly known as Spina Bifida. It is a defect of the embryonic structure that gives rise to the spinal cord and vertebral column. This defect leads to protrusion of the spinal cord and its coverings through a defect in the skin. The incidence of NTD in the world is one in every one thousand child birth.

Neural Tube Defects have different types namely:

1.
Spina Bifida: birth defect involving an abnormal opening of the spinal area.
2.
Spina bifida occulta: a common abnormality of spinal bones that usually does not have symptoms, but is sometimes associated with conditions that can require surgery.
3.
Meningocele: a birth defect in the bones of the spine that involves a swelling in the meninges, but no abnormality of the  spinal cord or nerve root.
4.
Myelomeningocele: a birth defect in the bones of the spine  with swelling of the meninges and abnormality of the spinal cord or nerve roots. It is the most severe among the four.

The condition is often associated with disruption of the cerebrospinal fluid pathways with a resulting hydrocephalus. The degree of neurological  deficit is directly related to the level of the spinal cord defect and its extent. If only the bottom of the spinal cord is involved  (conus), there may be only bowel and bladder dysfunction, while  the most extensive lesions can result in total paralysis of the  legs with accompanying bowel and bladder dysfunction. Other spinal disorders associated with NTD include, hip dislocation, and scoliosis  among others.