Tetanus patients exhibit when muscle spasms causes them to arch their backs.

Tetanus patients exhibit opisthotonos when muscle spasms cause them to arch their backs.

Explanation:

Tetanus is a bacterial infection caused by the bacterium Clostridium tetani The disease causing bacteria is found in dust, manure soil and saliva. This infection is characterized by muscle spasms that start at the jaw and progress to rest of the muscles of the body.

Tetanus patients may also exhibit extreme arched pose due to severe muscle spasms. This state of hyperextension and spasticity is known as opisthotonus.