Age / Sex : 47 / M

Age/sex: 47/M

C.C.: inability of left finger extension
        atrophy of left proximal forearm dorsoradial aspect (2YA)

posterior interosseous nerve syndrome

Discussion

Discussion

1. Posterior interosseous nerve

 - supinator muscle

 - extensor muscles of the wrist and hand :

     extensor digitorum communis, extensor digiti minimi,

     extensor carpi ulnaris, extensor pollicis longus and brevis, 

     abductor pollicis longus, and extensor indicis proprius muscles    * Superficial radial nerve

 - skin of the thumb, index, and middle fingers

2. Posterior interosseous nerve syndrome

- deep radial nerve syndrome or Supinator syndrome

- loss of motor function within muscles innervated by the posterior interosseous nerve

*** Radial nerve entrapment syndrome

 - Radial tunnel syndrome: significant neurologic deficit (-)

 - Posterior interosseous nerve syndrome: significant neurologic deficit (+)

-  Five potential compression sites,

  - proximal edge of the supinator muscle (arcade of Frohse) ; m/c

  - capsule of the radiocapitellar joint

  - small recurrent vessels that cross the posterior interosseous nerve (leash of Henry)

- the fibrous edge of the extensor carpi radialis brevis

- distal margin of the supinator muscle, where the posterior interosseous nerve exits the supinator tunnel

-  Causes of compression

   ; tumors, ganglion cysts, radiocapitellar synovitis, bicipital bursitis, fractures,

and dislocations of the radial head

-  Clinical manifestations

   ; insidious onset of pain

     weakness of the muscles innervated by the posterior interosseous nerve

   ; sensory intact

   ; complete/partial involvement

References

1.     MR imaging of entrapment neuropathies at the elbow ; Marcelo Bordalo-Rodrigues, MD, Zehava Sadka Rosenberg, MD*; Magn Reson Imaging Clin N Am 12 (2004) 247–263

2.     Peripheral Neuropathies of the Median, Radial, and Ulnar Nerves: MR Imaging Features, RadioGraphics 2006; 26:1267–1287

3.     2008 대한 근골격 학회 연수강좌 강의록