Final answer:
Myelomeningocele is a type of neural tube defect characterized by incomplete closure of the neural tube, leading to the protrusion of meninges and possibly neural tissue through the spine. It is the most severe form of spina bifida, often resulting in significant neurological symptoms. Adequate maternal folate intake is crucial for preventing this congenital defect.
Step-by-step explanation:
Myelomeningocele, also known as spina bifida, is a type of neural tube defect. This condition occurs when the neural tube, which forms early in the development of the nervous system, fails to close completely. This failure leads to parts of the meninges and possibly neural tissue protruding through the vertebral column. Within the classes of spina bifida, myelomeningocele is the most severe form, because it involves both the meninges and the spinal nerves, leading to severe neurological symptoms. A key factor in the prevention of neural tube defects such as spina bifida is adequate maternal intake of folate during the early weeks of pregnancy, as a deficiency can increase the risk of these defects occurring.