Most Common Types of Spina Bifida
Myelomeningocele (or meningomyelocele) the severest form in which the spinal cord,
and the dura mater protrude from the opening in the spine.  Because the spinal cord leaves
the protective bone tube of the spine and grows into the sack, damage to the nerves occurs
 at this point.  Urgent treatment is necessary to minimize further neurological damage and infection at the point of opening.  Below the nerve damage at the opening is where development of muscles and limbs can be affected.  Also, bowel and bladder function are frequently affected.  This is the most common form of spina bifida.  In some cases, the skin covering will be absent, requiring surgical closure.
 Meningocele is considered less severe than myelomeningocele because the spinal cord doesn't leave the protective bone tube. There is still a sack on the back, but the nerves of the spinal cord are not in it. Because the nerves remain protected, usually they are not damaged
as much. The person with this form of spina bifida usually has better physical development
and bowel and bladder control than one with myelomeningocele.
 Lipomyelomeningocele is an abnormal fat accumulation that starts below the skin and extends through an opening in the spine to the spinal cord. The skin covered lesion created
is found in the buttock and lower spine area, and is usually not painful. Symptoms, such as muscle weakness or loss of sensation in the lower legs and feet, and bowel or bladder incontinence occur due to compression of the nerves by the fatty mass (during periods of rapid weight gain) or the attachment of the fat to the spinal cord (tethering). Surgery may be required to release the tethering of the spinal cord to the fatty mass (especially during growth spurts) and to reduce the bulk of the fatty mass.
Occulta which means "hidden", indicates that the defect, where one or more vertebrae are malformed, is covered by a layer of skin. Occulta is the mildest form of spina bifida. An opening in the bone of the spine exists, but there is no sack or protruding of the spinal cord. The results of this form of spina bifida may include a sensitive depression (dimple) somewhere along the spine which often has long, dark hairs sticking out of it.  Also, bed wetting may be a problem for the individual with this type of spina bifida due to cord tethering.