Healing of a crush injury in rat striated muscle. 1. Description and testing of a new method of inducing a standard injury to the calf muscles.

In this report an apparatus is described which can quickly and reliably induce a standard crushing injury in a desired location of rat calf muscle without tearing the skin. To test the constancy of injury caused by the apparatus, both hind legs of rats were traumatized. Two days after traumatization, the rats were killed and the hind legs were inspected macroscopically and microscopically following prior formalin fixation. The breaking strength of the muscles was measured immediately after traumatization. In every case, the injury totally penetrated the medial head of the gastrocnemius muscle, but never damaged the whole jumping complex of muscles (gastrocnemius, plantaris and soleus). Both the location and the dimensions of the wound as well as the breaking strength of the injured muscles remained inside such narrow limits that the trauma can be regraded as constant.