J. Shaw‐Dunn

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 force-generating capacity of the subscapularis was equal to that of the other three muscles combined.

Cooper in 1840 described mammary branches from the 2nd-6th intercostal nerves, and noticed that the nipple was supplied by branches which lay close to the surface of the gland. Eckhard (1850) divided the mammary branches into superficial branches to the skin and nipple, and deep branches to the glandular tissue and nipple, but many later authors ignored those findings. After the second World War, cosmetic surgery of the breast made further research critical, as surgeons strove to design operations which would retain its shape and preserve postoperative sensation. Craig and Sykes (1970) described mainly anterior branches from the 3rd, 4th and 5th intercostal nerves passing through the glandular tissue of the breast and along the line of the ducts to the nipple, while Farina et al. (1980) concluded that the nipple was supplied solely by superficial lateral branches of the 4th nerve. Using improvements in dissecting technique learned from microsurgery, Sarhadi et al. (1996) found that the nipple was innervated by the lateral cutaneous branch of the 4th intercostal nerve, by two branches, one passing superficial to the gland, and the other through the retromammary space, and by variable lateral and medial additional branches from the 2nd-5th nerves. These branches came to lie superficially and formed a subdermal plexus under the areola. This account is uncannily close to Cooper's original description; it is a reassuring, if sobering, conclusion that his early account remains one of the most reliable.

Summary The ultrastructural changes in normal trophoblast maintained in organ culture are described. In well oxygenated conditions the fine structural integrity of the trophoblast is maintained up to 96 hours, and the tissue appears to function normally. Hypoxia quickly damages the syncytium and marked changes occur throughout the trophoblast, including apparent attempts at regeneration. These experimentally produced changes in hypoxia are very similar to the ultrastructural placental bnormalities already described in pre‐eclampsia, and more so to the placental abnormalities in placental insufficiency, which are described here for the first time. These similarities suggested that hypoxia is a primary aetiological factor in these conditions rather than an effect of the primary disease process.

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.