I have had two major shoulder surgeries. One surgery was for a detached Rhomboid muscle and detached low Trapezeis muscle. The second surgery was for the same trap muscle that came loose and fell of the muscle. I begged this doctor to operate again on me, because I experience the same pain before the first surgery. The orthropedic surgeon told me it wont come up on a mri, a detached rhomboid muscle or low trap muscle. Also, I ask him if it could be showed on a ultrasound of the Rhomboid and Trap Muscle. He brushed off this questions. I have read much information from ultrasound that it is good at seeing torn muscles. I cant get a straight answer. I am in unbearable pain. Thanks.
First, I am not a physician nor an ultrasound tech, so I am unfamiliar with the capability of musculoskeletal ultrasound on shoulders.
After a bit of research online, I found this .pdf file about positioning for ultrasound of the shoulder. None of the described exams would show a detached rhomboid muscle or low trap muscle. It looks like ultrasound is most helpful in diagnosing problems with the rotator cuff muscles & ligaments around the shoulder joint.
The rhomboid and low trapezius muscles attach to your shoulder blade or scapula. I was unable to find a way to visualize this area with ultrasound.
I am so sorry you're in such pain. I hope this info is useful to you.