An anatomic study of the coracoacromial Ligament was conducted. The da
ta collected from 20 anatomical preparations and the arthroscopic find
ings in 40 cases were compared. The shape and the tension of the ligam
ent were evaluated, as well as the thickness. Anatomic tradition descr
ibes the ligament as a fibrous triangular lamina inserted with its ape
x on the acromial tip and its base on the lateral edge of the coracoid
. It simply closes the coracoacromial arch and has no mechanical role,
However, our observations suggest that the ligament has a trapezoidal
shape and is situated below the acromion with a wide reflex portion.
Its thickness varies from 2 to 5.6 mm. Given that structure, the ligam
ent appears like a robust suspension structure of the coracoid, which
contrasts the action of the muscles that connect to it. From these obs
ervations, a pathogenic hypothesis of the subacromial impingement prop
oses itself.