This lesson is designed to illustrate joint actions in the upper extremity and the principal muscles responsible for those actions.

Shoulder Joint

• Abduction (248K)
  • Deltoid
  • Supraspinatus
  • *Serratus anterior and trapezius assist abduction past the horizontal plane.
• Adduction (247K)
  • Pectoralis major
  • Latissimus dorsi
  • *aided by teres major and subscapularis.
• Extension (386K)
  • Latissimus dorsi
  • Teres major
  • Posterior deltoid fibers
• Flexion (280K)
  • Pectoralis major
  • Anterior fibers of deltoid
  • Coracobrachialis
  • Biceps brachii (long head)
• Lateral rotation (282K)
  • Infraspinatus
  • Teres minor
  • *aided by posterior fibers of deltoid.
• Medial rotation (282K)
  • Subscapularis
  • Teres major
  • Pectoralis major
  • Latissimus dorsi
  • *aided by anterior fibers of deltoid.

Elbow Joint

• Extension (349K)
  • Triceps
  • *aided by anconeus.
• Flexion (383K)
  • Brachialis
  • Biceps brachii (especially when forearm is supinated)
  • *aided by brachioradialis and other muscles in flexor forearm compartment.

Radioulnar Joints

• Supination (307K)
  • Supinator
  • *biceps aids when there is resistance.
• Pronation (273K)
  • Pronator quadratus
  • *Pronator teres aids when there is resistance.

Wrist Joint

• Abduction (261K)
  • Flexor carpi radialis
  • Extensor carpi radialis longus and brevis.
• Adduction (279K)
  • Flexor carpi ulnaris
  • Extensor carpi ulnaris
• Extension (261K)
  • Extensor carpi radialis brevis and longus
  • Extensor carpi ulnaris
  • *aided by extensor digitorum.
• Flexion (372K)
  • Flexor carpi radialis
  • Flexor carpi ulnaris
  • *aided by flexors of the fingers.
• Circumduction - This is a combination of the above actions.

Movements of the Fingers

• Abduction (297K)
  • Dorsal interossei
• Adduction (297K)
  • Palmar interossei
• Extension (445K)
  • Extensor digitorum
  • *aided by lumbricals and interossei.
• Flexion (383K)
  • Flexor digitorum superficialis and profundus
  • Lumbricals
• The lumbricals act to flex of the metacarpo-phalangeal joint and extend the interphalangeal joints.

Movements of the Thumb

• Abduction (297K)
  • Abductor pollicis longus and brevis
• Adduction (259K)
  • Adductor pollicis
• Extension (370K)
  • Extensor pollics longus and brevis
• Flexion (296K)
  • Flexor pollicis longus and brevis
• Opposition (334K)
  • Opponens pollicis.

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John A. McNulty, Ph.D., Cell Biology, Neurobiology and Anatomy, LUMC

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John A. McNulty

Last Updated: May 2, 2000 Created: Mar 15, 1994