FUNCTIONAL-ANATOMY OF THE FLEXOR PRONATOR MUSCLE GROUP IN RELATION TOTHE MEDIAL COLLATERAL LIGAMENT OF THE ELBOW

To describe the relationship of the pronator teres, flexor carpi radia lis, flexor digitorum superficialis, and flexor carpi ulnaris muscles to the medial collateral ligament at 30 degrees, 90 degrees, and 120 d egrees of elbow flexion, we dissected 11 cadaveric specimens. The flex or carpi ulnaris muscle is the predominant musculotendinous unit overl ying the medial collateral ligament in the majority of cases and is th e only one at 120 degrees of elbow flexion. The flexor digitorum super ficialis muscle is the only other significant contributor. The medial collateral ligament is the primary stabilizer of the medial elbow with elbow flexion greater than 30 degrees, as in throwing. The flexor car pi ulnaris muscle, because of its position directly over the medial co llateral ligament, and the flexor digitorum superficialis muscle, with its near proximity and relatively large bulk, are the specific muscle s best suited to provide medial elbow support. This is especially rele vant to overhand throwing athletes who encounter extreme valgus force across the elbow during the cocking and acceleration phases of the thr owing motion. Exercise and conditioning of the medial elbow musculatur e, specifically the flexor digitorum superficialis muscle and the flex or carpi ulnaris muscle, may prevent injury or assist in rehabilitatio n of medial elbow instability, especially in overhand throwing athlete s.