OBJECTIVETo study the anatomical and biomechanical features of the interosseous membrane (IOM) of the cadaveric forearm.

METHODSTen radius-IOM-ulna structures were harvested from fresh-frozen cadavers to measure the length, width and thickness of the tendinous portion of IOM. Then, the tendinous portion was isolated along with the ulnar and radial ends to which the tendon attached after measurement. The proximal portion of the radius and the distal portion of the ulna were embedded and fixed in the dental base acrylic resin powder. The embedded specimen was clamped and fixed by the MTS 858 test machine using a 10 000 N load cell for the entire tensile test. IOM was stretched at a speed of 50 mm/min until it was ruptured. The load-displacement curve was depicted with a computer and the maximum load and stiffness were recorded at the same time.

RESULTSThe IOM of the forearm was composed of three portions: central tendinous tissue, membranous tissue and dorsal affiliated oblique cord. IOM was stretched at a neutral position, and flexed at pronation and supination positions. The tendinous portion of IOM was lacerated in 6 specimens when the point of the maximum load reached to 1021.50 N+/-250.13 N, the stiffness to 138.24 N/m+/-24.29 N/m, and the length of stretch to 9.77 mm+/-1.77 mm. Fracture occurred at the fixed end of the ulna before laceration of the tendinous portion in 4 specimens when the maximum load was 744.40 N+/-109.85 N, the stiffness was 151.17 N/m+/-30.68 N/m, and the length of the stretch was 6.51 mm+/-0.51 mm.

CONCLUSIONSThe IOM of the forearm is a structure having ligamentous characteristics between the radius and the ulna. It is very important for maintenance of the longitudinal stability of the forearm. The anatomical and biomechanical data can be used as an objective criterion for evaluating the reconstructive method of IOM of the forearm.