Opisthotonus

Excerpt

Opisthotonus is defined as a dramatic abnormal posture due to spastic contraction of the extensor muscles of the neck, trunk, and lower extremities that produces a severe backward arching from neck to heel. In most cases, the trunk is elevated off the ground by a few inches. It is usually sudden in onset and can be sustained or repetitive. It can be considered a variant of decerebrate posturing involving a hyperextension of the neck, back, and limbs. Sometimes it is referred to as arc de cercle. When the anterior abdominal muscle involvement is greater, emprosthotonus posture occurs where the body is arched anteriorly.