Heterotopic ossification complicating critical illness.

Heterotopic ossification (HO), deposition of para-articular ectopic bone, is associated with musculoskeletal trauma and certain congenital and metabolic disorders. Additionally, HO may follow paralysis from diverse traumatic and nontraumatic neurologic insults. We describe three cases of HO associated with catastrophic nontraumatic respiratory illness requiring prolonged chemical paralysis and cardiorespiratory support.