Carpal tunnel syndrome (CTS) is clinically defined asthe occurrence of hand and arm symptoms as a consequenceof compression of the median nerve at the wrist.Conventional nerve conduction studies are done to confirmthe diagnosis of CTS and exclude other causes A decrease offorearm median motor conduction velocity (CV) is a commonelectrophysiological finding in carpal tunnel syndrome (CTS),ascribed to two possible mechanisms: either conductionblock at the level of the wrist or slowing of the fastestmyelinating fibers in the carpal tunnel which lead toreduction of the forearm conduction velocity, or retrogradeaxonal atrophy (RAA) with retrograde conduction slowing(RCS) . This study included 20 patients with CTS and 10controls subjects for which conventional nerve conductionand forearm mixed studies were done., Mixed studiesincluded the direct and indirect mixed forearm conductionstudies applying their techniques to determine which is moresignificant and what is the pathophysiology that occurred atthe forearm. The indirect forearm mixed conduction studyshowed the highest sensitivity and suggested that thepathophysiology of forearm conduction reduction is due tothe RAA with RCS.