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Palmar Interosseous

Palmar Interossei

Description

Origin :

  • Dorsal 1 – 4: Adjacent sides of two metacarpals (bipennate muscles)
  • Palmar 1 – 3: Palmar surfaces of 2nd, 4th and 5th metacarpals (unipennate muscles)

Insertion :

  • Dorsal 1 – 4: Extensor expansions and bases of proximal phalanges of digits 2 – 4
  • Palmar 1 – 3: Extensor expansions of digits and bases of proximal phalanges of digits 2, 4 and 5

Innervation :

  • Deep branch of ulnar nerve (C8 and T1).

Arterial Supply :

  • Dorsal 1 – 4: Dorsal and palmar metacarpal arteries.
  • Palmar 1 – 3: Palmar metacarpal arteries.

Depth :

  • Superficial

Action

Action :

  • Dorsal 1 – 4: Abduct digits from axial line and act with lumbricals to
  • Palmar 1 – 3: Adduct digits toward axial line and assist lumbricals in joints.