what is primary impingement
Shoulder impingement can be subdivided into primary and secondary impingement. Primary im-pingement is a mechanical obstruc-tion of the rotator cuff tendons un-der the anterior inferior one-third of the acromion, the coracoacromial ligament, and sometimes the acro-mioclavicular joint (42).houlder impingement can be subdivided into primary and secondary impingement. Primary im-pingement is a mechanical obstruc-tion of the rotator cuff tendons un-der the anterior inferior one-third of the acromion, the coracoacromial ligament, and sometimes the acro-mioclavicular joint (42).