Updated: 11/7/2015

Posterior interosseous nerve

Review Topic
  • Origins
    • originates from the radial nerve at the radiohumeral joint line
  • Course
    • arcade of Frosche at radial head
      • dives under supinator at arcade of Frosche (thickened edge of between heads of supinator)
    • forearm posterior compartment
      • winds around radial neck within substance of muscle to posterior compartment of forearm
    • interosseous membrane
      • reaches interosseous membrane of forearm and ends as sensation to dorsal wrist capsule
    • dorsal wrist capsule
Motor Innervation

  • Motor
    • common extensors
      • ECRB (often from radial nerve proper, but can be from PIN) 
      • Extensor digitorum communis (EDC) 
      • Extensor digiti minimi (EDM) 
      • Extensor carpi ulnaris (ECU) 
    • deep extensors
      • Supinator 
      • Abductor pollicis longus (APL) 
      • Extensor pollicus brevis (EPB) 
      • Extensor pollicus longus (EPL) 
      • Extensor indicis proprius (EIP) 
Senory Innervation
  • Sensory
    • sensory fibers to dorsal wrist capusle
      • provided by terminal branch which is located on the floor of the 4th extensor compartment
    • no cutaneous innervation
  • PIN compression Syndrome 
    • in PIN palsy,  the last muscle to recover is the extensor indicis proprius 
  • Dorsal Approach to Radius (Thompson) 

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