Ultrasound appearance of normal and injured muscle tissue

The ultrasound image on the left shows the smooth, regular appearance of normal muscle tissue. In contrast, the image on the right shows an irregular, slightly hyperechoic (bright) area with a swirling appearance (arrows) consistent with intramuscular bleeding and hypoechoic (dark) areas (arrowheads) consistent with a tissue deficit. The deficit may be due to missing muscle or tendon tissue from a tear.