There are two major muscles located in the forearm that flex the fingers. They are the flexor digitorum superficialis and the flexor digitorum profundus. The flexor digitorum profundus is located just beneath the flexor superficialis.
Origin
It originates on the upper anterior and medial surfaces of the ulna.
Insertion
Insertion is by four tendons, which separate after passing the wrist and then go to the fingers.
Function
Flexes the fingers.