Trauma Team

What am I looking at?

This image depicts a human red blood cell trapped in traumatized muscle tissue that is showing signs of abnormal healing. The red blood cell is red (1), and the fibrous muscle tissue is gray (2).

Biology in the background

Muscle injury is a common problem in sports, military combat, and even daily life. In fact, if you’ve ever felt sore after exercising or otherwise exerting yourself, what you are feeling is tiny tears in your muscles, as well as a buildup of lactic acid, a byproduct of muscle metabolism. Muscles are generally very good at repairing such damage because it’s so common. Muscles can even build themselves back stronger after minor trauma, which is why your muscles get bigger after you’ve been working out for a while.

However, severe muscle damage can be more difficult for our bodies to repair – and sometimes the repair process can go wrong. The muscle tissue in this image is much more fibrous than muscle tissue should be, which is a sign of abnormal bone formation. This phenomenon is called heterotopic ossification, or the formation of bone outside the skeleton. It can happen after severe muscle damage, when the repair mechanisms of the body receive too much input or mixed input regarding which type of tissue they should be regenerating.

Human muscle cells are quite large – a muscle cell in an adult can be as long as 100 micrometers, or little bit more than the width of a human hair. An average human red blood cell, however, is only about 7 micrometers across, or roughly 10 times smaller than the width of a human hair.

Technique

This image was created using colored scanning electron microscopy.