O: bases of 2nd and 3rd metacarpals I: Medial side of base of proximal phalanx of thumb A: Draws 1st metacarpal laterally to oppose thumb toward center of palm and rotates it medially WikipediaQuestions
O: Hook of hamate and flexor retinaculum I: Medial side of base of proximal phalanx of little finger A: Flexes proximal phalanx of little (5th) finger WikipediaQuestions
O: Top of ulna I: Base of the distal phalanx of digits 2 - 5 A: Flexes distal phalanges at distal interphalangeal joints of medial four digits; assists with flexion of hand WikipediaQuestions
O: Humerus ulna head I: Bodies of middle phalanges of digits 2 - 5 A: Flexes middle phalanges at proximal interphalangeal joints of medial four digits; acting more strongly, it also flexes proximal phalanges at metacarpophalangeal joints and hand WikipediaQuestions
