Rachischisis (Greek: "rhachis - ῥάχις" - spine, and "schisis - σχίσις" - split) is a developmental birth defect involving the neural tube.

This anomaly occurs in utero, when the posterior neuropore of the neural tube fails to close by the 27th intrauterine day.

Patients with rachischisis have motor and sensory deficits, chronic infections, and disturbances in bladder function.

[7] If a sibling of the fetus has been affected by rachischisis, there is increased risk that another child will develop the condition.

[8] Folate deficiency is also a well-accepted risk factor of all neural tube defects, including rachischisis.

[11] Other neural tube defect diagnostic tools such as assays of α-fetoprotein or acetylcholinesterase may also be helpful in determining any other conditions that can lead to development of rachischisis.

Rachischisis occurs around 3–4 weeks after conception when the posterior neuropore of the neural tube does not close completely.

[citation needed] Rachischisis is a severe condition and survival rates for fetuses are extremely low.

Babies that are born with the condition have high mortality rates and extreme developmental defects.

Typically, medical termination of pregnancy is presented as an option to the mother once a diagnosis of rachischisis has been confirmed.

Treatments for neural tube defects such as spina bifida do not work as the child is not stable enough to receive them, or they are complicated by other accompanying conditions that have developed alongside rachischisis.