Clonus is a rhythmic, involuntary muscle contraction and relaxation that occurs in response to a sustained stretch. It is often caused by damage to the central nervous system, such as a stroke or spinal cord injury. Checking for clonus can help to identify the location and severity of the damage.
To check for clonus, the examiner will place the patient’s limb in a position where it is slightly stretched. They will then apply a quick, sharp force to the limb, which will cause it to flex or extend. If the limb continues to move rhythmically after the force is removed, this is a sign of clonus.
