T Nation

Lacertus Fibrosus Injury?


I suspect I may have a lacertus fibrosus injury and wonder if anyone has had experience with this.

Maybe a month ago, I first experienced some discomfort in my right forearm flexors while working out. (It felt like a string being pulled very tight, heading from the middle of the forearm up toward the medial epicondyle. It did not have the sharp sensations or burning sensation I have experienced with previous bouts of tennis elbow.) A day or so later I noticed a reddened area on my upper inner forearm flexors, maybe 2-3 inches below the joint. The redness never developed into a bruise and gradually faded away. I have periodically felt the same shooting tightness along my forearm flexors, but increasingly I began to feel some mild discomfort in the distal biceps tendon. Yesterday, for the first time, I noticed that the distal biceps tendon protrudes fairly noticeably compared to the left arm. I'm confident that I have not ruptured the distal biceps tendon. (I once tore the long head tendon of my other biceps, and I know that a tear would have MUCH more discomfort, swelling and shifting of muscle.) The only thing I have been able to come up with that seems plausible is that I might have torn/stretched the lacertus fibrosus, which appears to help anchor the distal biceps tendon and which appears to end in the same area where I experienced redness on my arm.

If anyone experience a lacertus fibrosus injury, I'm curious whether it allowed the distal biceps tendon to raise up where it was more visible than normal. Also, is a torn/stretched lacertus fibrosus something that would be expected to lead to later problems with the biceps tendon? Is it the kind of thing orthopedic folks would repair, and if so, what kind of recovery time is typical.

I will be making an appointment with an orthopedic guy I trust, but it takes a while to get in, so I'm looking for any practical experience/information folks might have in the meantime. (I plan to start wearing an elbow compression sleeve when I work biceps and closely monitor how things feel, but I'm not sure what else to do.)


I’ve never really heard of someone actually injuring their biceps at the insertion, it’s typically at the origin, so this is really interesting. Let me know what your “orthopedic guy” has to say about it!