Telemetric electromyographic analysis of muscle transferred to the os calcis.

Fifteen inphase muscle transfers to the os calcis from 11 patients with lower motor neuron paralysis were evaluated by means of telemetric electromyography during ambulation. In five of the limbs thus evaluated, electromyographic activity was found to resemble that of the normal triceps surae and had relatively normal proximal muscles. In ten limbs, contraction of the transferred muscle preceded heel strike. This was attributed primarily to proximal muscle weakness, which necessitated premature firing to ensure early knee extension during stance and hence to prevent the knee from buckling during weight-bearing.

Ultrastructures of nerve fibers and muscle spindles in adolescent idiopathic scoliosis.

Muscle biopsies were obtained from the erector spinae to investigate ultrastructural changes in nerve fibers and muscle spindles in patients suffering from adolescent idiopathic scoliosis. Membranous bodies are found in myelinated nerve fibers, both within and outside the muscle spindles. Leptofibrils are formed beneath the sarcolemma of the intrafusal muscle fibers. Additionally, in the intrafusal muscle fiber, there are slight increases in the amount of lipid droplets and glycogen particles, and the sarcoplasmic reticulum is slightly dilated. These changes may affect the metabolism of the muscle fiber and the normal balance of the contractile system. The cause-and-effect relationship of the changes in adolescent scoliosis warrants further investigation.

Effects of rheumatic mitral valvular disease and mitral valve replacement on growth and development.

The effects of rheumatic mitral valvular disease and mitral valve replacement on the growth and development of 37 Southern Chinese children were studied. The stature and body weight were measured before and after operation. All the patients had their skeletal maturity and cortical bone growth assessed after operation, but only 10 patients were similarly assessed before operation. At the time of operation the stature and body weight of all patients were generally retarded. The surgery which corrected the haemodynamic abnormality resulted in increases in the growth rates in stature and body weight but there was no evidence of a catch-up growth with subsequent return to normal dimensions. The patients who are skeletally immature had retarded bone ages and impaired growth of cortical bone. The general trend, though less marked, also showed a reduction in cortical bone in the skeletally mature patients. Surgery appears, at least partially, to alleviate the adverse effects of the disease on the growth and development of patients.

Anatomy of the femoral neck and head, with comparative data from Caucasians and Hong Kong Chinese.

The bony anatomy of the proximal femur consists of the femoral head, neck, and greater and lesser trochanters. In the adult the axis between the neck and the shaft averages 135 degrees. The femoral neck is anteverted from the transcondylar plane on the average 8 degrees in the adult. In measurements that we made of femora from cadavers of Caucasians, the anteversion angle averaged 7.0 degrees in males (range, --2 degrees to 35 degrees) and 10.0 degrees in females (range, -2 degrees to 25 degrees). Using similar techniques on cadavers of Hong Kong Chinese, we found that the average in males was 14.0 degrees (range, --4 degrees to 36 degrees) and 16.0 degrees in females (range, 7 degrees to 28 degrees). Normally the axis of the femoral head is parallel to the axis of the femoral neck, but specimens are found where there is retroversion of the femoral head. Sophisticated measurement techniques have confirmed the lack of roundness of the femoral head by establishing that the meridians have longer radii than the radii of the equator. Hence, the femoral head has a subtle egg or barrel shape. There are significant differences in the measurements of the head, neck, and proximal femoral shaft of average normal Caucasian and Hong Kong Chinese people.

Membranous bodies in the myelin sheath of Schwann cells.

Electron microscopy of muscle biopsies of patients with paralytic scoliosis and tuberculosis of spines reveals membranous bodies in the myelin sheath of Schwann cells. On the basis of this morphological pattern and indirect biochemical evidence, it is suggested that these bodies were formed by abnormal myelin metabolism.