1) Cramp 2) Muscle spasm 3) Spasm 
Latin, meaning: A disease where the body is curved backward. 
• (n.) A tetanic spasm in which the body is bent backwards and stiffened.
(opistho- + Gr. tonos tension) a form of spasm in which the head and the heels are bent backward and the body bowed forward.
<neurology> A form of spasm in which the head and the heels are bent backward and the body bowed forward. ... Origin: Gr. Tonos = tension ... (18 Nov 1997) ... 
(o″pis-thot´ә-nәs) a form of spasm in which the head and heels are bent backward and the body bowed forward. adj., opisthoton´ic., adj.
Op`is·thot'o·nos noun [ New Latin , from Greek ... backwards + ... a stretching.] (Medicine) A tetanic spasm in which the body is bent backwards and stiffened. 
Type: Term Pronunciation: ō′pis-thot′ō-nŭs Definitions: 1. A tetanic spasm in which the spine and extremities are bent with convexity forward, the body resting on the head and the heels.
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 sig...
Opisthotonos is a tetanus-like muscular contraction spasm in which the body is bent backwards and stiffened.
[n] - severe spasm in which the back arches and the head bends back and heels flex toward the back
characteristic symptom of tetanus that results in uncontrolled muscular spasms and backward arching of the neck and spine
noun severe spasm in which the back arches and the head bends back and heels flex toward the back
A disease where the body is curved backward.