the osterior compartment of the forearm These mu8cle8 are innervated by the deep branch of radial nerve also known as the po8terior interosseous nerve of the forearmn Supinator muscle Abductor pollicia longu8 muscle xtensor pollicis brevis muscle Etensor pollicis longus muscle EItensor digitorum muscle The erten8or pollicis ongua i8 a long and slender mu8cle The extensor ollicis brevis on the other hana is a brevis on the other hana is a bit shorter 1t originates from the posterior 8urface of the distal one third of the 8haft of the ulna and the adjacent intero88e0u8 membrane of the forearm The muscle fibers8 form a belty which travels down inferiorty and lateraliy just 8uperior to the wrist joint This betty forma a tendon which Cro88e8 the wrist and travela down towards the th umb The deep branch of the O d 0l m orano snu hndi oR nmm ost radiat nerve 8upplies almoat all the p08terior musclea of the forearm Thi8 nerve 8upply i8 also referred to a8 the posterior interosseou8 nerve of the forearm A ateral view of the forearm 8hows the radial nerve and its branch that suphlies the dee muacles of the posterior Compartment of the forearm