the medical term opisthotonos (backward bending tone) means
Opisthotonus 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.[1][2] This abnormal posturing is an extrapyramidal effect and is caused by spasm of the axial muscles along the spinal column.
Obturator sign The principles of the obturator sign in the diagnosis of appendicitis are similar to that of the psoas sign. The appendix is commonly located in the retrocecal or pelvic region. The oburator sign indicates the presence of an inflamed pelvic appendix.