Primary idiopathic polymyositis does not involve:-

Answer is C (Ocular muscles): 'Ocular muscles are almost never affected' - Harrison. Occular muscles are spared, even in advanced untreated cases - Harrison Primary idiopathic polymyositis: Condition of autoimmuneQ etiology in which skeletal muscle is damaged by non suppurative inflammatory process) dominated by Lymphocytic infiltration!) It is characterized by: Symmetrical weakness of proximal limb muscles especially hips and thigh (pelvic girdle) and later shoulder girdle. Weakness of flexor muscles of neck Involvement of striated muscles of pharynx (dysphagia) Involvement of respiratory muscles (late) "Ocular muscles are almost never affected except in a rare case associated with myasthenia gravis. 'Facial muscles are unaffected in Polymyositis'. - Harrison