Overview of the hand muscles

introduction

The muscles of the hand and fingers are divided into three groups:

  • The muscles of the ball of the thumb (Thenar muscles),
  • the muscles of the metacarpal and
  • the muscles of the little finger ball (Hypothenary group).

All muscles are innervated by the median or ulnar nerve and are primarily used for fine motor skills.

function

The hand muscles are particularly useful Fine motor skills and with it all everyday movements of the fingers.
Because of this, the muscles of the hand are numerous, however relatively smallto be able to control movements that are as fine as possible.
General hand muscle movements include diffraction (Flexion) and Elongation (Extension), Bring up (Adduction) and Spreading (Abduction) and the Opposition movements of thumb and little finger.
This means that these two fingers can be moved onto the palm of the hand.

Illustration of the hand muscles

Right hand image: A - palm (superficial and middle layer) and B - back of the hand

Hand muscles
I - muscles of the ball of the little finger
Hypothenary group (green)
II - muscles of the ball of the thumb
Thenar muscles (blue)
III - Metacarpal muscles (red)

  1. Little finger spreader -
    Abductor digiti minimi muscle
  2. Short little finger flexor -
    M. flexor digiti minimi brevis
  3. Short palm tendon tensioner -
    Muscle palmaris brevis
  4. Little finger counteracting device -
    M. opponens digiti minimi
  5. Thumb pull -
    Muscle abductor pollicis
  6. Short thumb flexor -
    Muscle flexor pollicis brevis
  7. Short thumb spreader -
    Muscle abductor pollicis brevis
  8. Thumb counter -
    Muscle opponens pollicis
  9. Spinal muscles -
    Lumbrical muscles
  10. Palm side intermediate
    bone muscles -
    Palmar interossei muscles
  11. Elbow-sided hand flexor -
    Flexor carpi ulnaris muscle
  12. Spoke-sided hand flexor -
    Flexor carpi radialis muscle
  13. First back intermediate
    bone muscle -
    Muscle interosseus dorsalis I
  14. Long thumb stretcher -
    Extensor pollicis longus muscle
  15. Short thumb straightener -
    Extensor pollicis brevis muscle
  16. Short spoke-side hand straightener -
    Extensor carpi radialis brevis muscle
  17. Long spoke-side hand straightener -
    Extensor carpi radialis longus muscle
  18. Backhand intermediate
    bone muscles -
    Dorsal interossei muscles
  19. Finger extensor -
    Extensor digitorum muscle
  20. Klenfingerstrecker -
    Extensor digiti minimi muscle
  21. Extensor tendon strap -
    Retinaculum musculorum extensorum
  22. Ellenside hand extensor -
    Extensor carpi ulnaris muscle

You can find an overview of all Dr-Gumpert images at: medical illustrations

Muscles of the ball of the thumb (thenar muscles)

The group of the ball of the thumb includes four muscles, which start in the area of ​​the thumb and so the Thumb movements exercise.

  • The Abductor pollicis brevis muscle arises from one of the carpal bones (Scaphoid bone= Scaphoid bone) and attaches to the distal limb of the thumb (proximal phalanx). It essentially shapes the ball of the thumb and causes a saddle joint in the thumb Splay, as well as a Opposition movementi.e. the movement of the thumb on the palm of the hand. The thumb is flexed at the base of the thumb and extended at the end of the thumb. The innervation is carried out by the Median nerve. This also innervates
  • the Opponens pollicis muscle. It arises from a carpal bone and starts on the radial side (spoke side) at the base joint of the thumb. As the name suggests, this muscle is primarily used for Opposition movement.
  • The Flexor pollicis brevis muscle is separated into two muscle bellies. The superficial part (Caput superficiale) originates from the flexor retinaculum and is innervated by the median nerve. The deep part (Caput profundum) has its origin in three carpal bones and is through the Ulnar nerve controlled. Both parts start together on the basal phalanx of the thumb. The superficial part spreads the thumb (Abduction), the deep part pulls it back in (Adduction). In addition, both shares are in the Opposition movement of the thumb involved.
  • Also the Adductor pollicis muscle has two heads, which arise on different carpal bones. Together they start at the ulnar (medial) sesamoid bone of the thumb and primarily cause the Introduction (adduction) the thumb on the hand. This muscle is also supported by the Ulnar nerve provided.

Metacarpus muscles

The Metacarpus muscles are again divided into three major muscle groupswhich each have the same function and the same course, but on different fingers.

  • The Musculi (Mm.) Lumbricales arise from the 2nd to 5th tendons of the flexor digitorum profundus muscle. Together they radiate into the dorsal aponeurosis of the 2nd to 5th finger, which is on the extensor side. you bend all fingers 2 (index finger) to 5 (little finger) in the base joint and stretch them in the middle and end joint.
    The Mm. Lumbricales of fingers 2 and 3 (index finger and middle finger) are passed through the Median nerve innervated, fingers 4 and 5 (ring finger and little finger) by the Ulnar nerve.
  • The Mm. Interossei dorsales arise on the facing sides of the 1st to 4th metacarpal bones and attach to the dorsal aponeurosis of fingers 2 to 5. you Bend and spread the fingers in the metatarsophalangeal joint and stretch them in the middle joints. These muscles are powered by the Ulnar nerve innervated.
  • The Mm. interossei palmares are a group of three muscles that arise on the metacarpal bones of fingers 2, 4 and 5 and attach to the dorsal aponeurosis of the corresponding finger. you bend and close (adduction) the fingers in the metatarsophalangeal joint and stretch them in the middle finger joints. This muscle group is also supported by the Ulnar nerve controlled.

Muscles of the ball of the little finger (hypothenary group)

All four muscles this group are through the Ulnar nerve innervated.

  • The Abductor digiti minimi muscle The carpal bone arises from the pea bone (os pisiforme) and attaches to the lateral base of the metacarpal joint 5. He spreads the little finger.
  • The Flexor digiti minimi muscle also arises from a carpal bone (Hamulus ossis hamati) and attaches to the side of the metacarpophalangeal joint of the little finger. in the In this way, the basic joint leads to the flexion of the little finger, in the In the middle and end joints, he stretches his little finger.
  • The Opponens digiti minimi muscle also arises from the hamulus ossis hamati and attaches to the metacarpal bone of the 5th finger. He does one Opposition movement of the little finger, so moves it to the palm of your hand.
  • The Palmaris brevis muscle serves less for movement than that Tightening and tensioning of the skin over the ball of the little finger. For this it finds its origin in the aponeurosis of the palm and starts at the ball of the little finger.