What congenital defect consists of the absence of a vertebral arch of the spinal column?

Spina bifida is a congenital defect that occurs when the vertebral arch of the spinal column fails to form properly before birth. This condition causes a range of symptoms, including paralysis, deformity, and hydrocephalus (buildup of fluid in the brain). The other options, including cataracts, meningitis, and osteoporosis, are not associated with the absence of a vertebral arch of the spinal column and are therefore incorrect. Cataracts are an age-related eye condition, meningitis is an inflammation of the protective membranes surrounding the brain and spinal cord, and osteoporosis is a bone disease that causes bones to become weak and brittle. While all of these conditions can occur at any age, they are not typically classified as congenital defects.