Clonus is defined as recurrent uninhibited contraction of a skeletal muscle [ often a group of muscles ] to persistent stretch.  This may result due to disease affecting the  pyramidal tract and occasionally extra-pyramidal tract. The video shows the classical ankle clonus which is obtained by  supporting the leg by holding the upper part of the calf muscle just below popliteal fossa  and  passive   dorsiflexion of  the ankle joint. This passive dorsiflexion  should be quick and the stretch  must be sustained for sometime. The   video shows recurrent  oscillation of the  ankle joint due to persistent contraction of the muscles contributing to achiles tendon [  gastronemius and soleus ] .The quick  passive dorsiflexion is maintained for 20 seconds in the video. This patient was suffering from cerebro-vascular accident . Presence of  sustained clonus indicates a severe pyramidal tract involvement. An ill sustained clonus for few seconds may occur in anxious patients and those suffering from psychiatric illness.  

Launch video     Published: 06-Sep-2010 05:55:36 PM GMT   Views: 5527