Final answer:
Spina bifida occulta is usually seen at lower vertebral levels. It is the mildest form of spina bifida and may not cause noticeable functional differences.
Step-by-step explanation:
Spina bifida occulta is usually seen at lower vertebral levels. In this type of spina bifida, the vertebral bones do not fully surround the spinal cord, but the spinal cord itself is not affected. It is considered the mildest form of spina bifida and may not cause noticeable functional differences.