Houston Methodist. Leading Medicine

Shoulder FAQ


I'm reading the pathology report of tissue taken from my frozen shoulder. I'd like to understand what really caused my problem. Can you tell me what collagen fibers are? There's a lot of mention of several types of collagen.


Collagen is an important protein that provides structural support for almost all tissues and organs in the body. The word collagen comes from the Greek meaning glue producer.

There are at least 28 known types of collagen in the body. Scientists are discovering more types every year. Most of the structural collagen in the body is Type I. This type forms skin, tendon, bones, and teeth. Type II is found in certain types of cartilage such as the ear, nose, and joints.

Type III collagen is seen mostly in blood vessels and organs. It is also the most common kind found in the developing fetus (child in uterus). Other types of collagen form parts of the eye, tendons, bone, and lymphatic vessels.

Types I and III collagen are found in the shoulder both normally and as a result of fibrous scar tissue. Research has shown that inflammation is not really present in a frozen shoulder. It's more likely the presence of a protein called vimentin in the anterior or front part of the shoulder capsule. Finding out what causes the increased vimentin to form is the next step. Hans K. Uhthoff, MD, FRCSC, and Pascal Boileau, MD. Primary Frozen Shoulder. In Clinical Orthopaedics and Related Research. March 2007. No. 456. Pp. 79-84.

*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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