Aims. – Description of a pain leg caused by accessory soleus muscle. An accessory soleus muscle would be in among 6% of individuals, in a bilateral way in two cases out of free. Five anatomic shapes have been described. Mostly asymptomatic, this anatomic variant can appear, above all during the effort, by leg pains such as cramps. A simple hard intern lateral achileus swelling can be emphasised without any other physical sign. The association of an accessory soleus muscle with an equines varus club-foot has been described. The magnetic resonance imaging confirms the positive diagnosis. The treatment for the disabling shapes is based on the exeresis of the supernumerary soleus muscle. Conclusion. – It would be advised to stop the physical activities which cause the pains and to redirect to other activities which less needs the use of the flexor muscular complex of the ankle.