Palmar Interossei

Joe Muscolino

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The palmar interossei intrinsic muscles of the hand. The adductor pollicis has been ghosted in.

The Palmar Interossei muscles are members of the Central Compartment Group of intrinsic muscles of the hand, composed of the:

 

There are three Palmar Interossei muscles, named #1, #2, and #3, from radial/lateral (thumb side) to ulnar/medial (little finger side).

 

ATTACHMENTS:

  • The palmar interossei attach from metacarpals #2, #4, and #5 to the proximal phalanges of fingers #2, #4, and #5 on the “middle-finger side.”
    • Palmar interosseus #1 attaches onto finger #2 (index finger).
    • Palmar interosseus #2 attaches onto finger #4 (ring finger).
    • Palmar interosseus #3 attaches onto finger #5 (little finger).
    • The palmar interossei also attach distally into the dorsal digital expansion.

 

ACTIONS:

  • Adducts fingers #2, #4, #5 at the metacarpophalangeal joints.
  • Flexes fingers #2, #4, #5 at the metacarpophalangeal joints.
  • Extends fingers #2, #4, #5 at the proximal and distal interphalangeal joints.

 

NOTES:

  1. Because the palmar interossei attach onto their respective fingers on the “middle-finger side,” they bring those fingers toward the middle finger, which is defined as adduction.
  2. There is a mnemonic for remembering the abductors/adductors of the fingers: DAB PAD – Dorsals ABduct Palmars ADduct.