ANATOMIC BASIS OF DORSORADIAL APPROACH FOR RADIOULNAR SYNOSTOSIS

The object of this study was to identify the best approach for exposin g the radioulnar interosseous membrane while protecting the posterior interosseous n. (PIN). Twenty paired upper limbs were used to obtain m easurements of the PIN and expose the distal two-thirds of the interos seous membrane in the forearm through a dorsoradial approach. The leng th of the PIN from the radial head to the arcade of Frohse (AF) was 26 .5 +/- 1.6 mm in males and 25.3 +/- 1.I mm in females. The length of t he PIN between the radial head and the point where the PIN exits from the supinator was 66.7 +/- 4.7 mm in males and 63.0 +/- 2.5 mm in fema les. The length of the PIN covered by the supinator was 44.0 +/- 0.5 m m in males and 37.0 +/- 0.5 mm in females. The distance between the po int where the PIN exits from the supinator and the lateral margin of t he radius was 15.0 +/- 0.9 mm in males and 14.5 +/- 0.9 mm in females. The distance between the exit point of the PIN from the supinator and the lateral margin of the ulna was 18.2 +/- 0.6 mm in males and 17.9 +/- 0.7 mm in females. The distance from the point where the most late ral branch of the PIN entered the abductor pollicis longus (APL) to th e lateral margin of the radius was 3.5 +/- 0.5 mm. In 20 cadaveric upp er limbe, the middle and distal portions of the inter-osseous membrane were exposed through the interval between the extensor carpi radialis brevis (ECRB) an extensor digitorum communis (EDC) m., after the orig ine of the extensor pollicis brevis (EPB), and extensor pollicis longu s (EPL) mm. had been elevated from the lateral margin of the radius. T he present study suggests that usina dorsoradial approach facilitates exposure of the middle and distal portions of tl-ie interosseous membr ane.