Lewis & Short

ŏpisthŏtŏnĭa, ae, f., = ὀπισθοτονία, a disease in which the head is drawn backwards, opisthotony (post-class.); opp. emprosthotonia, in which the head is drawn forwards, Cael. Aur. Acut. 3, 6; cf. Hier. Ep. ad Ephes. 6, 4; v. opisthotonos.