Carrier detection in Duchenne muscular dystrophy

[Possibilities and limits of interpretation of muscle sonograms. An experimental study of standardized muscle injuries]

After sonographical examination we performed surgically an experimental muscle injury of known size and location on 28 New Zealand white rabbits by a stab with a scalpel into the supraspinatic muscle. The changes in the healing process were sonographically followed and documented for 2 months in short periods of time. The sonographically detectable changes during the healing process underlie a regularity. The changes in sonography can be explained by histopathology with respect to the theoretics of ultrasound physics. The development of a hematoma and of fibrous scars can be followed up by sonography with respect to some limits. Sonography is shown to be a supporting method of high value in the diagnosis of muscle injuries and with respect to certain limits in the follow-up of the healing process, too.

Size and strength of the quadriceps muscles of old and young women

Muscle weakness and wasting may be evaluated objectively by dynamometry and compound ultrasound imaging. We have measured the voluntary isometric strength of the quadriceps muscles of healthy women in their 70s (n = 25) and in their 20s (n = 25) and have compared it with the mid-thigh cross-sectional area of the same muscles. The two groups of women showed similar variability when strength was measured on consecutive days (coefficients of variation: 8%). The older women were 35% weaker than the young women (P less than 0.001) and their quadriceps cross-sectional area was 33% less (P less than 0.001). Quadriceps strength and cross-sectional area were correlated (r = 0.66, P less than 0.001, elderly; r = 0.53, P less than 0.01, young) and the principal axis of the relationship was closely similar for the two groups of women. There is therefore no difference in the intrinsic strength of the quadriceps muscles of healthy women in their third and eighth decades. This report also provides normative data for the objective evaluation of quadriceps weakness and/or wasting in female patients. The techniques involved are straightforward, the dynamometer is easily made, and compound ultrasound imaging is widely available.