The proximal hamstring muscle-tendon-bone unit: a review of the normal anatomy, biomechanics, and pathophysiology

Proximal hamstring injuries occur during eccentric contraction with the hip and the knee on extension; hence they are relatively frequent lesions in specific sports such as water skiing and hurdle jumping. Additionally, the trend toward increasing activity and fitness training in the general population has resulted in similar injuries. Myotendinous strains are more frequent than avulsion injuries. Discrimination between the two types of lesions is relevant for patient management, since the former is treated conservatively and the latter surgically. MRI and Ultrasonography are both well suited techniques for the diagnosis and evaluation of hamstring tendon injuries. Each one has its advantages and disadvantages. The purpose of this article is to provide a comprehensive review of the anatomy and biomechanics of the proximal hamstring muscle-tendon-bone unit and the varied imaging appearances of hamstring injury, which is vital for optimizing patient care. This will enable the musculoskeletal radiologist to contribute accurate and useful information in the treatment of athletes at all levels of participation.