Hand muscles

Anterior view of the forearm, wrist, and hand showing the muscles that act on the anterior wrist and hand

The wrist connects the hand to the forearm and is essential for hand movements such as waving or writing. The wrist joint, or radiocarpal joint, facilitates flexion/extension as well as abduction (movement away from the body) and adduction (movement toward the body) of the wrist.

These movements are made possible by the forearm muscles that run across the forearm and attach with their tendons to different parts of the hand.

The forearm muscles that move the hand are grouped as follows:

  • Flexor muscles which are organized into a superficial, intermediate and deep layer and primarily flex the hand and pronate the forearm
  • Extensor muscles which are organized into a superficial and deep layer and primarily extend the hand and supinate the forearm 

All of these muscles are located at the forearm and span across the wrist to move the hand.

However, the hand also has intrinsic muscles that allow movements of the fingers as well as fine adjustments for complex and more precise tasks.

The hand muscles are organized into five groups:

  • Thenar muscles: Abductor pollicis brevis, adductor pollicis, flexor pollicis brevis and opponens pollicis. The thenar muscles are located at the palmar side of the base of the thumb and allow flexion, abduction, adduction and opposition of the thumb.
  • Hypothenar muscles: Abductor digiti minimi, flexor digiti minimi, opponens digiti minimi and palmaris brevis. The hypothenar muscles make up the fleshy part of the palmar base of the 5th finger (hypothenar eminence) and allow flexion, abduction, lateral rotation and opposition of the 5th finger.
  • Lumbricals are positioned between the metacarpal bones and provide flexion in the metacarpophalangeal joint and extension in the interphalangeal joints.
  • Palmar interossei lie between the metacarpal bones and attach to the 2nd, 4th and 5th finger to provide finger adduction and support both flexion and extension.
  • Dorsal interossei are located on the adjacent sides of the metacarpal bones 1-4 to abduct the digits 2-4 and assist with flexion and extension.

Discover the anatomy of these muscles with interactive diagrams below. Learn even faster with this forearm muscle revision guide. 

Featured image showing three images of the anterior forearm. The image on the left shows the bony elements and the muscles of the anterior forearm, the middle image shows the bony elements and isolated Flexor Carpi Ulnaris muscle, and the image on the right shows the attachments of the Flexor Carpi Ulnaris muscle connected by a transparent muscle itself.
Flexor Carpi Ulnaris

A tutorial on the position, actions, attachments and innervation of the Flexor Carpi Ulnaris muscle with the aid of detailed anatomical illustrations.
Featured image showing three images of the anterior forearm. The image on the left shows the bony elements and the muscles of the anterior forearm, the middle image shows the bony elements and isolated Palmaris Longus muscle, and the image on the right shows the attachments of the Palmaris Longus muscle connected by a transparent muscle itself.
Palmaris Longus Muscle

A tutorial on the position, actions, attachments and innervation of the Palmaris Longus muscle with the aid of detailed anatomical illustrations and a quiz.
Featured image showing three images of the anterior forearm. The image on the left shows the bony elements and the muscles of the anterior forearm, the middle image shows the bony elements and isolated Flexor Carpi Radialis muscle, and the image on the right shows the attachments of the Flexor Carpi Radialis muscle connected by a transparent muscle itself.
Flexor Carpi Radialis

A tutorial on the position, actions, attachments and innervation of the Flexor Carpi Radialis muscle with the aid of detailed anatomical illustrations.
Featured image showing three images of the anterior forearm. The image on the left shows the bony elements and the muscles of the anterior forearm, the middle image shows the bony elements and isolated Flexor Digitorum Superficialis muscle, and the image on the right shows the attachments of the Flexor Digitorum Superficialis muscle connected by a transparent muscle itself.
Flexor Digitorum Superficialis Muscle

A tutorial on the position, actions, attachments and innervation of the Flexor Digitorum Superficialis muscle with the aid of anatomical illustrations.
Featured image showing three images of the posterior forearm. The image on the left shows the bony elements and the muscles of the posterior forearm, the middle image shows the bony elements and isolated Extensor Carpi Radialis Longus muscle, and the image on the right shows the attachments of the Extensor Carpi Radialis Longus muscle connected by a transparent muscle itself.
Extensor Carpi Radialis Longus

An interactive tutorial showing the location, attachments, actions and innervation of Extensor Carpi Radialis Longus muscle using anatomical illustrations.
Featured image showing three images of the posterior forearm. The image on the left shows the bony elements and the muscles of the posterior forearm, the middle image shows the bony elements and isolated Extensor Carpi Radialis Brevis muscle, and the image on the right shows the attachments of the Extensor Carpi Radialis Brevis muscle connected by a transparent muscle itself.
Extensor Carpi Radialis Brevis Muscle

An interactive tutorial showing the location, attachments, actions and innervation of Extensor Carpi Radialis Brevis muscle using anatomical illustrations.
Featured image presenting three views of the extensor digitorum. The image on the left shows muscles of the posterior forearm and wrist, the middle image shows the isolated extensor digitorum muscle, whereas the image on the right shows its attachments.
Extensor Digitorum Muscle

An interactive tutorial showing the location, attachments, actions and innervation of Extensor Digitorum muscle using anatomical illustrations.
The featured image for extensor carpi ulnaris muscle. The view on the left shows the bony elements and the soft structures of the posterior forearm and the wrist, the middle image shows the isolated extensor carpi ulnaris muscles, the image on the right shows the its attachments connected by a transparent extensor carpi ulnaris muscle.
Extensor Carpi Ulnaris – Attachments, Action & Innervation

Extensor Carpi Ulnaris is one of the muscles that comprise the superficial compartment of the posterior forearm compartment. Arising from the common origin of extensors to insert on the base of the fifth metacarpal after running between the EDM and the anconeus.