Fig. 4.

Pincer impingement. Owing to acetabular over-coverage, the femoral neck abuts against the hip labrum, damaging the labrum and eventually the underlying cartilage. A contre-coup lesion can also occur, where continued flexion of the hip, after the femoral neck is already abutting against the acetabular rim, causes subtle joint subluxation and damage to the acetabular cartilage. The labrum separates from the cartilage and the acetabular cartilage delaminates from the bone [46]

(reproduced with permission from Springer)