
Originally Posted by
physiobob
Looks to me like your humeral head moves up and anterior during the external rotation in an abnormal way. This suggests a structure that is involved in maintaining the position of the head is damaged in some way. This could even be an internal rotator that was working with the lats in an inner range of a single arm pull-up. Having said that there are a lot of possible structures. Really you need an MRI of the shoulder and upper humerus to look at all tendons, including the biceps. The video from the back showing what your scapulae are doing is also showing very abnormal movement of both the left side and also the humeral head in relation to it.