Two unrelated children were born with severe congenital malformations: a girl now seven years old and a boy who died in the newborn period. Both had severe cervical hyperextension, severe flexion deformities of the limbs, and bilateral popliteal pterygia. Postmortem examination of the second case showed small, well-formed thoracic vertebrae with mild epidural fibrosis and hemorrhage. These births defects are rare and usually occur separately. We postulate that they are related in these two cases; that the arthrogryposis and popliteal pterygia were probably the result of the spondylohypoplasia and associated changes; and that together, these related defects may constitute a new malformation complex.