Name Flexor pollicis longusPronunciation (FLEK-sur POL-uh-sus LONG-gus) Origin/Proximal Attachment Middle anterior surface of radius interosseous membrane (may also originate from lateral border of coronoid process or medial epicondyle) Insertion/Distal Attachment Palmar aspect of base of distal phalanx of thumb (deep to flexor retinaculum) Action/Relevance Flexes the distal phalanx of the thumb Flexes the other joints to the wrist (Metacarpophalangeal, Carpometacarpal, & weakly at the wrist joints) Innervation Anterior interosseous branch of median nerve (C8, T1) | 
