This is a congenital malformation of the embryonic neural tube and spinal cord. The vertebral(neural) arches are absent and the dura mater is abnormal,most commonly in the lumbosacral region. The causes are not known,although the condition is associated with dietary deficiency of folic acid at the time of conception. These neural tube defects may be of genetic origin or due to environmental factors,eg.irradation,or maternal infection(rubella)at a critical stage in development of fetal vertebrae and spinal cord. The effects depend on the extent of the abnormality.
OCCULT SPINA BIFIDA.
In this’hidden’ condition the skin over the defect is intact and excessive growth of hair over the site may be the only sign of abnormality. This is sometimes associated with minor nerve defects that commonly affect the bladder.
MENINGOLE.
The skin over the defect is very thin and may rupture after birth. There is dilation of the subarachnoid space posteriorly. The spinal cord is correctly positioned.
