Shoulder impingement syndrome - Neer classification

Neer classification divides lesions of the rotator cuff into three stages that typically succeed in this order during one's life.

Stage Description Age group
Stage I actue inflammation, edema, hemorrhage in the rotator cuff younger patients <25 years
Stage II progression to fibrosis and tendinitis of the rotator cuff usually between 25 and 40 years
Stage III mechanical disruption of the rotator cuff tendons (tear), changes in the coracoacromial arch and osteophytes along the acromion usually >40 years


1. Neer CS 2nd. Impingement lesions. Clin Orthop Relat Res. 1983 Mar;(173):70–7
2. Chang WK. Shoulder impoingement syndrome. Phys Med Rehabil Clin N Am. 2004;15:493–510

3. NeerII CS. Anterior Acromioplasty for the Chronic Impingement Syndrome in the Shoulder. J Bone Joint Surg Am. 2005 Jun 1;87(6):1399–1399.