[1][2] The lumbrical muscles of the foot also have a similar action, though they are of less clinical concern.

The lumbricals are four, small, worm-like muscles on each hand.

Instead, they attach proximally to the tendons of flexor digitorum profundus,[1][2][3] and distally to the extensor expansions.

[2][4] The first and second lumbricals (the most radial two) are innervated by the median nerve.

[7] The lumbrical muscles, with the help of the interosseous muscles, simultaneously flex the metacarpophalangeal joints while extending both interphalangeal joints of the digit on which it inserts.