<Tr> <Th_colspan="2"> Opisthotonus </Th> </Tr> <Tr> <Td_colspan="2"> Opisthotonus in a patient suffering from tetanus . Painting by Sir Charles Bell, 1809 . </Td> </Tr> <P> Opisthotonus or opisthotonos, from Greek roots, ὄπισθεν, opisthen meaning "behind" and τόνος tonos meaning "tension", is a state of severe hyperextension and spasticity in which an individual's head, neck and spinal column enter into a complete "bridging" or "arching" position . This abnormal posturing is an extrapyramidal effect and is caused by spasm of the axial muscles along the spinal column . </P> <P> It is seen in some cases of severe cerebral palsy and traumatic brain injury or as a result of the severe muscular spasms associated with tetanus . It can be a feature of severe acute hydrocephalus . </P>

The medical term opisthotonos (backward bending tone) means