We studied five cadaver shoulders to determine the strength relationship of the four rotator cuff muscles. The mean fibre length and volume of each muscle were measured, from which the physiological cross-sectional area was calculated. This value was used to estimate the force which each muscle was capable of generating. The lever arm of each muscle about the humeral head was then measured and the moment exerted was calculated. The strength ratios between the muscles were more or less constant in the five specimens. Subscapularis was the most powerful muscle and contributed 53% of the cuff moment; supraspinatus contributed 14%, infraspinatus 22% and teres minor 10%. The forcegenerating capacity of the subscapularis was equal to that of the other three muscles combined.

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The lateral surgical approach to the proximal femur potentially damages the nerve supply to the vastus lateralis (VL) muscle. This study describes the detailed anatomy of the nerve supply to the VL muscle based on dissection of ten cadaveric lower limbs. In all specimens, a single nerve trunk arose from the femoral nerve, which is most subsequently divided into two main divisions. These divisions gave two branches each. These branches coursed from anteriorly and proximally to posteriorly and distally within the muscle. When the muscle was reflected anteriorly from its attachment to the linea aspera, there was no damage to its innervation. Splitting of the VL in the midlateral line of the femur, however, resulted in denervation of the posterior half of the muscle. Precise knowledge of the nerve supply to the VL will help avoid iatrogenic denervation of the muscle in surgical procedures at the proximal femur through the lateral approach.

Summary Using a pulsed ultrasound technique, the human fetal heart rate was studied between 45 days and 15 weeks after the first day of the last menstrual period. The heart rate rose from a level of 123 beats per minute at 45 days to a peak of 177 beats per minute at 9 weeks, and then gradually fell to a value of 147 beats per minute at 15 weeks. In cases of threatened abortion the fetal heart rates were not statistically different from those in normal pregnancies. The changes in heart rate were correlated with the morphological and physiological changes which occur in the fetal heart during this period.