A tuft of hair at the base of the spine in a newborn is a sign of which condition?

A tuft of hair at the base of the spine in a newborn is a sign of which condition?

• A. Spina bifida
• B. Meningocele
• C. Anencephaly
• D. Hydrocephalus

Answer: (A)

A tuft of hair at the base of the spine signals occult spinal dysraphism, most commonly spina bifida occulta. This milder form involves incomplete fusion of the vertebral arches without a protruding sac, so external skin markers like hair tufts can be the only clue. The other conditions involve more obvious defects: a meningocele would show a sac-like protrusion of meninges, anencephaly is a cranial neural tube defect with severe brain and skull absence, and hydrocephalus is an accumulation of CSF in the brain—none of which are suggested by a hair tuft alone.

A tuft of hair at the base of the spine signals occult spinal dysraphism, most commonly spina bifida occulta. This milder form involves incomplete fusion of the vertebral arches without a protruding sac, so external skin markers like hair tufts can be the only clue. The other conditions involve more obvious defects: a meningocele would show a sac-like protrusion of meninges, anencephaly is a cranial neural tube defect with severe brain and skull absence, and hydrocephalus is an accumulation of CSF in the brain—none of which are suggested by a hair tuft alone.