"origin: lateral epicondyle of humerus"
"insertion: middle, distal phalanges on dorsal surface; extensor expansions of digits 2-5"
"arterial supply: radial recurrent artery, posterior interosseous artery"
"innervation: posterior interosseous nerve (C7, C8), a continuation of the deep branch of the radial nerve (C7, C8)"
"action: extension in metacarpophalangeal joint"
"insertion: middle, distal phalanges on dorsal surface; extensor expansions of digits 2-5"