Dynamic testing while patient abducts a positive impingement sign can be identified when the humerus can be seen striking the acromion in real time suggesting significant rotator cuff pathology
here we have the linear scanner in the longitudinal plane of the rotator cuff slid just anterior so we can capture the humeral head and the acromion in a single view and this is to show dynamic impingement where we have the patient try and abduct where normally as the patient abducts the humeral head will dip underneath the acromion smoothly this patient is experiencing discomfort as the humeral head strikes against the acromion here suggestive of significant rotator cuff pathology and a positive impingement test and you can even see the discontinuity of the humeral cortex here either from repeated trauma and striking of the acromion or from where the rotator cuff came evolved from the bone and caused damage to the bone itself you
