Figure 1.

(A) This ultrasonographic image is a cross-sectional view of the left forearm, obtained at approximately the upper third of the forearm. The ulna (U) is on the left side of the screen. The flexor digitorum profundus muscle (*) is directly adjacent to the ulna, and in this case, it is hyperechoic and atrophic. The flexor carpi ulnaris muscle (arrow) is adjacent to the flexor digitorum profundus muscle and has normal echotexture and size. Atrophic and hyperechoic flexor digitorum adjacent to normal flexor carpi ulnaris is the pattern consistent with IBM. (B) The same ultrasonographic view is presented in a healthy individual. No muscle atrophy is detected and the same structure as in image A are labelled.