Actions Of The Arm Muscles

Front 1

anconeus

Back 1

Located on the back of the humerus, it extends the forearm.

Front 2

extensor digiti minimus

Back 2

A long narrow muscle located on the ulnar side of the extensor digitorum communis muscle. It assists in extension of the wrist and little finger.

Front 3

extensor digitorum communis

Back 3

Positioned in the center of the forearm along the posterior surface. Its tendon divides into four tendons beneath the extensor retinaculum, which attach to the distal tips of fingers one through four.

Front 4

flexor digitorum profundus

Back 4

Lies just underneath the flexor digitorum superficialis muscle. This muscle flexes the distal ends of the fingers (but not the thumb).

Front 5

pronator teres

Back 5

Positioned in upper middle part of the forearm. It arises from the epicondyle (a prominence or projection on a bone). It turns the hand downwards (called pronation) and flexes the elbow.

Front 6

flexor pollicis longus

Back 6

Positioned deep on the front of the radius. It attaches at the base of the thumb and flexes the thumb and makes grasping possible.

Front 7

epicondyle

Back 7

A prominence or projection on a bone.

Front 8

pronator quadratus

Back 8

Positioned deep and extends between the ulna and radius. It works with the other pronator muscle to rotate the palm of the hand down, as well as position the thumb medially.

Front 9

supinator

Back 9

Positioned around the upper portion of the radius. It works with the biceps to turn the palm upwards (called supination).

Front 10

pollex

Back 10

the first digit of the hand (thumb)