dysraphism

The defective fusion of a raphe, especially of the neural folds.

Incomplete closure of a raphe, e.g. of the neural tube. The defect may be complete or partial.

• spinal d. — an inherited defect in Weimaraner dogs and reported in many other breeds. From an early age, affected puppies show varying degrees of ‘bunny hopping’, symmetrical and simultaneous use of the back legs, often overextending them before stepping forward. More severe defects have associated musculoskeletal abnormalities and may be a cause of perinatal death.
• sternal d. — congenital split of the sternum; may be associated with peritoneopericardial diaphragmatic hernia.