[Ultrastructural changes of human skeletal muscle after tendon and nerve injuries. I. Fine-structural changes of the hand muscles after tendor injuries (author's transl)]

The effect of tourniquet ischaemia on intact, tenotomized and motor nerve injured human hand muscles

Ultrastructural examination of the intrinsic hand muscles was performed on young healthy patients undergoing reconstructive operation following tendon or nerve lesions. The muscle specimens were taken at the start and then every fifteen to twenty minutes until the end of the tourniquet ischaemia. The authors have not found any morphological alterations following the use of a tourniquet up to two hours in either the intact or previously injured muscles.

Capillary density of tenotomized skeletal muscles. I. Experimental study in the rat

Our purpose was to study the capillary density of rat gastrocnemius muscle by microangiography 7-21 days after achillotenotomy or immobilization in a plaster cast. Sixteen animals were tenotomized, 12 immobilized in a plaster cast, and 4 served as controls. The number of capillaries was counted per 1,000 muscle fibres from each sample. No site differences were found in control muscles, where on an average 1,250 capillaries per 1,000 muscle fibers were found. After tenotomy the number of capillaries was decreased 35%, 31%, and 32% on days 7, 14, and 21, respectively. In immobilized muscles the decrease in capillary density occurred slowly, the corresponding decrease being 23%, 33%, and 28% on days 7, 14, and 21, respectively. These results indicate that the capillary density of muscular tissue is greatly decreased following the disuse produced by tenotomy or immobilization.

Histochemical and ultrastructural study of human muscles after spontaneous rupture of the tendon

The authors studied the histochemical and ultrastructural alterations of human muscles after spontaneous rupture of the tendon. Both succinate dehydrogenase (in type 1 fibres), and ATPase (in type 2 fibres) activity decreased in all injured muscles. In the intact antagonists and in contralateral muscles alterations were not found. The creatine phosphokinase and aldolase activity were decreased also in the injured muscles. The lactate dehydrogenase activity was various both in affected and in unaffected antagonists muscles. 2 weeks or more after the rupture of the tendon, in the injured muscles the number of type 1 fibres were decreased and therefore a statistically significant type 2 fibre predominance occurred. Ultrastructurally the disruption and disorientation of the myofibrils, streaming and disorganisation of Z line were found. The sarcolemma was arranged, the sarcoplasmic reticulum was dilated; both normal, pycnotic and enlarged mitochondria were observed. The motor end-plates were not discernible.