Dorsal Interossei

• Dorsal Interossei:

  • 4 bipennate muscles

  
• O (origin):

  • Sides of adjacent metacarpals

  A) Dorsal Interossei

  
• R (direction):

  • Distally

  A) Dorsal Interossei

  
• I (insertion):

  • Dorsal digital expansions and bases of proximal phalanges of digits 2 – 4

  A) Dorsal Interossei

  
• A (action):

  • Abduction and flexion of metacarpophalangeal joints of digits 2 - 4
  • Extension of interphalangeal joints (through dorsal digital expansion)

  A) Dorsal Interossei

  
• NS (nerve supply):

  • Deep branch ulnar nerve (C7 - T1)

  A) Dorsal Interossei