Myelomeningocele is a birth defect in which the backbone and
spinal canal do not close before birth. The condition is a type
of spina bifida. Spina bifida; Cleft spine Causes, incidence,
and risk factors Normally, during the first month of a
pregnancy, the two sides of the spine (or backbone) join
together to cover the spinal cord, spinal nerves and meninges
(the tissues covering the spinal cord). Spina bifida refers to
any birth defect involving incomplete closure of the spine.
Myelomeningocele is the most common type of spina bifida. It is
a neural tube defect in which the bones of the spine do not
completely form, resulting in an incomplete spinal canal. This
causes the spinal cord and meninges (the tissues covering the
spinal cord) to stick out of the child's back. Myelomeningocele
may affect as many as 1 out of every 800 infants. The rest of
spina bifida cases are most commonly: Spina bifida occulta, a
condition in which the bones of the spine do not close but the
spinal cord and meninges remain in place