Extensor Quadriga: Pathomechanics and Treatment

The extensor tendons to the index, long, ring and small fingers are motored by the common extensor digitorum communis muscle body. Effective function of this muscle can only occur if the gliding amplitude of each of its four extensor tendons is normal. As a corollary, limitation of the excursion of any of the individual tendons by adhesions at a fracture or tendon repair site, a fixed flexion contracture at the metacarpophalangeal joint, or by rupture, attenuation or laceration of a saggital band or juncturae tendinum, will result in reduction of the excursion of the adjacent extensor tendons. This pathological state has been termed the extensor quadriga because of its similarities to the analogous pathology affecting the flexor digitorum profundus system. Improper management of this clinical entity may lead to an abnormal pathomechanical kinematic chain imbalance. Early identification and treatment is critical to address this entity appropriately.