Extensors

• Extensor Digitorum
  • Bony Attachments:
    • 1: Common extensor tendon of lateral humerus
    • 2: Extensor expansion of 2nd-5th digits
  • Innervation: Radial nerve (C7, C8)
  • Arterial supply: Interosseous artery
  • Action: Extends the metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of the 2nd-5th digits and extends the wrist
• Extensor Carpi Ulnaris
  • Bony Attachments:
    • 1: Common extensor tendon on humerus and proximal posterior ulna
    • 2: Proximal medial 5th metacarpal
  • Innervation: Radial nerve (C7, C8)
  • Arterial supply: Ulnar artery
  • Action: Extends the wrist, adducts the hand
• Extensor Carpi Radialis Longus
  • Bony Attachments:
    • 1: Common extensor tendon on humerus
    • 2: Dorsum of 2nd metacarpal
  • Innervation: Radial nerve (C6, C7)
  • Arterial supply: Radial artery
  • Action: Extends the wrist, abducts the hand
• Extensor Carpi Radialis Brevis
  • Bony Attachments:
    • 1: Common extensor tendon of the humerus
    • 2: Dorsum of 3rd metacarpal
  • Innervation: Posterior interosseous n., branch of radial n. (C7, C8)
  • Arterial supply: Radial artery
  • Action: Extends the wrist, abducts the hand
• Extensor Digiti Minimi
  • Bony Attachments:
    • 1: Common extensor tendon on humerus
    • 2: Extensor digitorum tendon of the 5th digit and extensor expansion
  • Innervation: Radial nerve (C7, C8)
  • Arterial supply: Interosseous artery
  • Action: Extends the metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of the 5th digit
• Extensor Indicis
  • Bony Attachments:
    • 1: Interosseous membrane and distal ulna
    • 2: Extensor digitorum tendon of the 2nd digit and extensor expansion
  • Innervation: Radial nerve (C7, C8)
  • Arterial supply: Interosseous artery
  • Action: Extends the metacarpophalangeal, proximal interphalangeal and distal interphalangeal joints of the index finger
• Extensor Pollicis Brevis
  • Bony Attachments:
    • 1: Interosseous membrane and distal radius
    • 2: Proximal phalanx of thumb
  • Innervation: Radial nerve
  • Arterial supply: Interosseous artery
  • Action: Extends the metacarpophalangeal joint of the thumb
• Extensor Pollicis Longus
  • Bony Attachments:
    • 1: Interosseous membrane and mid shaft of the ulna
    • 2: Distal phalanx of thumb
  • Innervation: Radial nerve
  • Arterial supply: Interosseous artery
  • Action: Extends the thumb at the interphalangeal joint