The quantification of the origin area of the deep forearm musculature on the interosseous ligament.

: The diagnosis and treatment of injuries involving rupture of the interosseous ligament remain challenging. Few studies have considered the effects of rupture of the interosseous ligament on deep forearm muscle function. The objective of this study was to quantify the attachment areas of the deep forearm muscles on the interosseous ligament. The origins of the extensor indicis, extensor pollicis longus, extensor pollicis brevis, abductor pollicis longus, lexor pollicis longus, and lexor digitorum profundus were digitized from 11 cadavers. Three-dimensional modeling techniques were used to quantify the origin area on bone and the interosse- ous ligament. The extensor pollicis longus and the abductor pollicis longus attached primarily to the interosseous liga- ment (81% and 62%, respectively). Although the other deep forearm muscles had larger origins on bone, relatively large areas on the interosseous ligament were observed, ranging from 31% to 47%. The muscle origins on the interosseous ligament were veriied histologically, where striated muscle originated directly from the dense connective tissue of the interosseous ligament. Due to their relatively large attach- ment areas on the interosseous ligament, the function of the deep forearm muscles might be altered after an interos- seous ligament rupture. Therefore, symptoms such as pain and weakness of the deep forearm muscles could serve as a basis for screening patients with injuries of the interosse- ous ligament. Furthermore, the data may help to elucidate factors limiting the healing of the interosseous ligament. Future studies should focus on quantifying the effect of an interosseous ligament rupture on the function of the deep forearm muscles and developing reconstructions that con- sider this function.