Subcoracoid impingement is a relatively obscure syndrome. Guided by studies conducted by Gerber and Patte since 1985, the authors began to select cases of periarticular disease of the shoulder in which there was clinical evidence of involvement of the subcoracoid space. These patients underwent repeated clinical examination, radiographic examination according to Bernageau, CT scan, and Arthro-CT. All patients were tested with a novocaine infiltration into the subcoracoid space. This paper contains a precise diagnostic protocol that has evolved from the studies conducted by Gerber and Patte. Of the 23 patients selected, 3 were advised to undergo surgical widening of the subcoracoid space, consisting of resection of the coracoacromial and coracohumeral ligaments and special, reductive coracoidplasty.