Final answer:
The condition described is called spina bifida, which is a birth defect of the spinal cord caused by the failure of the neural tube to completely close.
Step-by-step explanation:
The condition described, where there is a persistent connection between the amniotic cavity and the spinal canal due to the failure of the neuropores to fuse, is called spina bifida. Spina bifida is a birth defect of the spinal cord caused when the neural tube does not completely close, resulting in the emergence of meninges and neural tissue through the vertebral column.
Example: In ultrasound images, spina bifida can be seen as a fetal myelomeningocele, which is the protrusion of spinal tissue through the newborn's vertebral column.