RT Book, Section
A1 Malone, Terry R.
A1 Hazle, Charles
A1 Grey, Michael L.
SR Print(0)
ID 5940894
T1 Chapter 7. Imaging of the Forearm, Wrist, and Hand
T2 Imaging in Rehabilitation
YR 2008
FD 2008
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-154946-2
LK accessphysiotherapy.mhmedical.com/content.aspx?aid=5940894
RD 2024/04/20
AB In  the  forearm,  reference  to  normal  anatomic  relationships  begins  with  the  radius  and  ulna,  proximal  to  distal.  The  distal  radioulnar  joint  is  a  critical  articulation  in  forearm  pronation  and  supination.  This  joint  has  a  separate  synovial  compartment  and  bordered  distally  by  the  triangular  fibrocartilage  (May,  2002).  Generally,  the  radial  styloid  process  extends  beyond  the  ulnar  styloid  process  by  approximately  9  to  12  mm.  At  the  proximal  articular  surface  of  the  lunate,  however,  the  two  bones  are  of  approximately  of  the  same  level.  An  ulna  of  less  length  provides  for  negative  ulnar  variance,  and  a  longer  ulna  is  described  by  a  positive  ulnar  variance.  The  normal  arrangement  of  the  distal  ulna  and  radius  provides  for  the  radial  angle  (also  known  as  the  ulnar  slant  or  ulnar  inclination),  which  is  usually  measured  at  15  to  25  degrees.  The  distal  surface  of  the  radius  also  demonstrates  an  orientation  toward  the  palmar  or  volar  surface  of  approximately  10  to  25  degrees  (Greenspan,  2000;  May,  2002).  These  anatomic  relationships  are  critical  in  imaging  assessment  for  the  orthopedist,  both  in  assessing  for  pathology  and  in  planning  the  appropriate  course  of  intervention  (Figures  7–1  and  7–2).