Opisthotonus

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The words Opisthotonos or opisthotonus stem from the Greek language, opistho for behind and tonos for tension. Opisthotonus is seen as a severe hyperextension and spastic tendency in which the individual enters a complete "bridging" or "arching" position with the head, neck and spinal column arching backward in extreme extension.. This abnormal posturing is an extrapyramidal effect and is caused by spasm of the axial muscles along the spinal column. It is posturing seen in individuals with severe cerebral palsy or traumatic brain injury, or in the severe muscular spasms associated with tetanus. It can be produced experimentally in animals by transection of the midbrain (between superior and inferior colliculus which results in severing all the corticoreticular fibers. Hyperextension occurs because facilitation of anterior reticulospinal tract due to removal of inhibitory corticoreticular fibers to the pons reticular formation. Infants and children display opisthotonos more often more exaggeratedly. Opisthotonus in infants may be apparent in the first hours of life. This marked extensor tone can cause infants to "rear backwards" and stiffen out as the mother or nurse attempts to hold or feed them. Opisthotonus can be induced by any attempt at movement such as smiling, feeding, vocalization, or by seizure activity. Individuals with opisthotonus are quite challenging to position, especially in wheelchairs and car seats.