Proximal muscle weakness, polymyositis Left thigh: There are varying degrees of abnormal increased signal and enhancement involving nearly all of the musculature of the thigh with the short head of the biceps femoris appearing relatively spared. These changes are more evident within the proximal musculature compared to distally. There is no fatty atrophy of the musculature. The bone marrow signal of the femur is normal.Right thigh: There are varying degrees of abnormal increased signal and enhancement involving nearly all of the musculature of the thigh with the short head of the biceps femoris appearing relatively spared. These changes are more evident within the proximal musculature compared to distally. There is no fatty atrophy of the musculature. The bone marrow signal of the femur is normal.
Bilateral and symmetric inflammation of the thigh muscles indicating polymyositis.