Definition of Opisthotonos

Opisthotonos: A great rigid spasm of the body, with the back fully arched and the heels and head bent back. Opisthotonos occurs in meningitis, especially in infants, due to irritation of the membranes surrounding the brain and spinal cord. It also occurs with depressed brain function and injury to the brain. Opisthotonos is an ominous neurologic sign.