The forearm is the most common site for compartment syndrome in the upper extremity. The three compartments of the forearm include the volar (anterior or flexor), the dorsal (posterior or extensor), and the mobile wad. Both-bone forearm fractures and distal radius fractures are common initial injuries in adults that lead to acute forearm compartment syndrome. Supracondylar fractures, especially those with associated vascular injuries, are frequent causes of compartment syndrome in children. The flexor digitorum profundus and flexor pollicis longus are among the most severely affected muscles because of their deep location, adjacent to bone. Initial treatment consists of removal of occlusive dressings or splitting or removal of casts. If symptoms do not resolve rapidly, fasciotomy is indicated. Decompression fasciotomy of the forearm is performed through volar or dorsal approaches. The medial nerve is decompressed throughout its course, including high-risk areas deep to the lacertus fibrosus; between the humeral and ulnar heads of the pronator teres, the proximal arch, and deep fascial surface of the flexor digitorum superficialis; and the carpal tunnel.