I have it! This was a fun post, I had no idea this was a vestigial muscle and honestly it is a little surprising because it looks like it is doing something when it pops out like it is doing in your picture.

I am always a little skeptical when I hear a claim that a part of the body is "useless" or has no function - sure it might be true, or we just might not have figured it out yet... and often the latter turns out to be the case (see "junk" DNA, the appendix, etc.). When it comes to a muscle/tendon however it seems pretty straightforward - if removed is there a loss of range of motion or strength? It kind of blows my mind that in this case the answer is no.

Cheers - Carl