Action of Lumbricals is
Flexion at Metacarpo - Phalangeal joint and flexion at Interphalangeal joint Extension at Metacarpo - Phalangeal joint and extension at Interphalangeal joint Flexion at Metacarpo - Phalangeal joint and extension at Interphalangeal joint Extension at Metacarpo - Phalangeal joint and flexion at  Interphalangeal joint