Muscles-Actions-Upper Extremity

Front 1

05. Abductor Digiti Minimi

Back 1

Abducts, assists in opposition, and may assist in metacarpophalangeal joint flexion. May assist in interphalangeal joint flexion.

Front 2

06. Palmaris Longus

Back 2

Tenses palmar fascia, flexes wrist, may assist in elbow flexion.

Front 3

07. Extensor Indicis (superior muscle in photo)

Back 3

Extends metacarpophalangeal joint, extends interphalangeal joints of index (w/ lumbricalis and interossei). May assist in index finger adduction

Front 4

08. Extensor Digiti Minimi

Back 4

Extends the metacarpophalangeal joint, and in conjunction with the lumbricalis and interosseous, extends the interphalangeal joints of the little finger. Assits in abduction of little finger

Front 5

09. Extensor Digitorum (inferior in photo)

Back 5

Extends the metacarpophalangeal joints, and in conjunction with the lumbricales and interossei, extends interphalangeal joints of the second through fifth digits. Assists in abduction of the index, ring, and little fingers and in extension and abduction of the wrist.

Front 6

10. Flexor Digitorum Superficialis

Back 6

Flexes the proximal interphalangeal joints of the second through fifth digits, and assists in flexion of the metacarpophalangeal joints and in flexion of the wrist.

Front 7

11. Flexor Digitorum Profundis

Back 7

Flexes the distal interphalangeal joints of the index, middle, ring, and little fingers, and assists in flexion of the proximal interphalangeal and metacarpophalangeal joints. May assist in flexion of the wrist

Front 8

12. Flexor Carpi Radialis

Back 8

Flexes and abducts the wrist, and may assist in pronation of the forearm and in flexion of the elbow.

Front 9

13. Flexor Carpi Ulnaris

Back 9

Flexes and adducts the wrist, and may assist in in flexion of the elbow.

Front 10

14. Extensor Carpi Radialis Longus and Brevis (inf in photo)

Back 10

Extends and abducts the wrist, and assists in elbow flexion (longus) Extends and assists in abduction of the wrist (brevis)

Front 11

15. Extensor Carpi Ulnaris

Back 11

Extends and adducts the wrist

Front 12

16. Pronator Teres

Back 12

Pronates the forearm, and assists in flexion of the elbow joint

Front 13

17. Pronator Quadratus

Back 13

Pronates the forearm.

Front 14

18. Supinator

Back 14

Supinates the forearm.

Front 15

19. Biceps Brachii

Back 15

Flexes the shoulder joint. The short head assists with shoulder adduction. The long head may assist with abduction if the humerus is laterally rotated. With the origin fixed, flexes the elbow joint, moving the forearm toward the humerus and supinates the forearm.With the insertion fixed, flexes the elbow joint, moving the humerus toward the forearm, as in pull-up or chinning exercises.

Front 16

20. Brachialis

Back 16

With the origin fixed, flexes the elbow joint, moving the forearm toward the humerus. With the insertion fixed, flexes the elbow joint, moving the humerus toward the forearm, as in pull-up or chinning exercises.

Front 17

21. Triceps Brachii

Back 17

Extends the elbow joint. The long head also assists in adduction and extension of the shoulder joint.

Front 18

22. Brachioradialis

Back 18

Flexes the elbow joint, and assists in pronating and supinating the forearm when these movements are resisted.

Front 19

23. Coracobrachialis

Back 19

Flexes and adducts the shoulder joint.

Front 20

24. Supraspinatus

Back 20

Abducts and laterally rotates the shoulder joint, and stabilizes the head of the humerus in the glenoid cavity during these movements.

Front 21

25. Infraspinatus

Back 21

Laterally rotates the shoulder joint, and stabilizes the head of the humerus in the glenoid cavity during movements of this joint.

Front 22

26. Teres Minor (inf in photo)

Back 22

Laterally rotates the shoulder joint, and stabilizes the head of the humerus in the glenoid cavity during movements of this joint.

Front 23

27. Subscapularis (ventral surface)

Back 23

Medially rotates the shoulder joint, and stabilizes the head of the humerus in the glenoid cavity during movements of this joint.

Front 24

28. Teres Major

Back 24

Medially rotates, adducts, and extends the shoulder joint.

Front 25

29. Deltoid

Back 25

Abduction of the shoulder joint, chiefly by the middle fibers, with stabilization by the anterior and posterior fibers. In addition, the anterior fibers flex and, in the supine position, medially rotate the shoulder joint.Posterior fibers extend amd, in prone position, laterally rotate the shoulder joint.

Front 26

30. Pectoralis Major (upper)

Back 26

With origin fixed, adducts and medially rotates the humerus. With the insertion fixed, it may assist in elevating the thorax, as in forced inspiration. In crutch walking or parallel-bar work, it will assist in supporting the weight of the body.

Front 27

31. Pectoralis Minor

Back 27

With origin fixed, tilts scapula anteriorly. With scapula stabilized to fix the insertion, assists in forced inspiration.

Front 28

32. Latissimus Dorsi

Back 28

With the origin fixed, medially rotates, adducts and extends the shoulder joint.By continued action, depresses the shoulder girdle and assists in lateral flexion of the trunk.With the insertion fixed, assists in tilting the pelvis both anteriorly and laterally. Acting bilaterally, this muscle assists in hyperextending the spine and anteriorly tilting the pelvis or in flexing the spine, depending on its relation to the axes of motion. Additionally, may act as an accessory muscle of respiration.

Front 29

33. Rhomboids

Back 29

Adduct and elevate the scapula, rotate it so that the glenoid cavity faces caudally.

Front 30

34. Levator Scapulae

Back 30

, laterally flexes cervical vertebrae, rotates toward same side. Bilaterally: may assist in extension in cervical spine.

Front 31

35. Trapezius

Back 31

Fixed origin:adduction of scapula, chiefly middle fibers, with stabilization by upper and lower fibers. Rotation of scapula so glenoid cavity faces cranially. Upper fibers elevate, lower fibers depress scapula. Fixed insertion unilaterally: upper fibers extend, laterally flex, and rotate the head and joints of cervical vertebrae so face turns toward opposite side. Insertion fixed bilaterally: extends neck. Accessory of respiration.

Front 32

36. Trapezius

Back 32

Fixed origin:adduction of scapula, chiefly middle fibers, with stabilization by upper and lower fibers. Rotation of scapula so glenoid cavity faces cranially. Upper fibers elevate, lower fibers depress scapula. Fixed insertion unilaterally: upper fibers extend, laterally flex, and rotate the head and joints of cervical vertebrae so face turns toward opposite side. Insertion fixed bilaterally: extends neck. Accessory of respiration.

Front 33

37. Serratus Anterior

Back 33

With the origin fixed, abducts the scapula, rotates the inferior angle laterally and the glenoid cavity cranially, and holds the medial border of the scapula firmly against the rib cage. In addition, the lower fibers may depress the scapula, and the upper fibers may elevate it slightly.