Innervation: All of the interosseous muscles of the hand are innervated by the deep branch of the ulnar nerve. Actions: The palmar interosseous muscles adduct the fingers towards the middle finger. This is in contrast to the dorsal interossei, which abduct the fingers away from the middle finger. In addition (like dorsal interossei) they flex the finger at the metacarpo-phalangeal joint and extend the finger at the interphalangeal joint and thus assist the lumbricals. Pollical Palmar Interosseous Muscle (of Henle, PPIM) It is currently accepted that more than 80% of individuals present a pollical palmar interosseous muscle (of the thumb) as suggested by Henle’s description in 1858 and verified by numerous investigations such as those carried out by Randall S. Susman, Lukhanyo Nyati, and Mandeep S. Jassal. |