[Torsion dystonia of the left upper limb probably due to a head injury. Calcification of the head of the right caudate nucleus discovered by tomodensitometric examination].

A young man (30 years) suffered a head injury in the course of a road accident. Four years after the accident, there was progressive development of hypertonia of the muscles of the left shoulder in association with certain movements, with torsion dystonia of the left upper limb. The presence of minimal neurological signs differentiated this cases from so-called idiopathic torsion dystonia. Tomodensitometry revealed an opacity of the head of the right caudate nucleus which was invisible on standard skull films. The authors discuss the physiopathology problems raised by this special case.