<prompt> Involvement of which of the following muscles virtually excludes the diagnosis of polymyositis?Neck musclesExtraocular musclesEsophageal musclesAbdominal muscle  <response>: Ans. b Extraocular muscles Ref. Harrison 18th ch. 388POLYMYOSITIS acquired myopathy characterized by subacute symmetrical weakness of proximal limb and trunk muscles When a characteristic skin rash violacious papules occurs, the disease is known as dermatomyositis. Patients often have dysphagia and neck muscle weakness. Laboratory findings include an elevated serum CK level, an EMG showing myopathic potentials with fibrillations, and a muscle biopsy showing necrotic muscle fibers and inflammatory infiltrates.It is characterized by: Symmetrical weakness of proximal limb muscles especially hips and thigh 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 Facial muscles are unaffected in polymyositis.DERMATOMYOSITIS characteristic Heliotropic rash: blue purple discoloration of upper eye lids with edema. Gottronfs patch: Erythema of knuckles with a raised violaceous scaly eruption. Flat red rash on face and upper trunk. Sheet-like soft tissue calcification 