TY  - CHAP
M1  - Book, Section
TI  - Boutonnière and Swan-Neck Deformities
A1  - Breed, Meghan
A1  - Fitch, Robert Warne
A2  - Knoop, Kevin J.
A2  - Stack, Lawrence B.
A2  - Storrow, Alan B.
A2  - Thurman, R. Jason
PY  - 2021
T2  - The Atlas of Emergency Medicine, 5e
AB  - The  boutonnière  deformity  results  from  injury  to  the  central  slip  insertion  of  the  extensor  hood  on  the  dorsal  surface  of  the  middle  phalanx.  After  a  tear  of  the  central  slip,  the  flexor  tendon  is  unopposed  at  the  PIP  and  the  lateral  bands  of  the  extensor  tendon  contract.  With  time,  these  displace  volarly,  resulting  in  additional  PIP  joint  flexion  and  DIP  joint  extension.  The  central  slip  rupture  may  result  from  forceful  flexion  of  the  PIP  joint  during  full  extension,  a  dorsal  PIP  joint  laceration,  or  a  palmar  PIP  joint  dislocation.  The  deformity  may  not  be  immediately  apparent  as  it  takes  time  for  the  lateral  bands  to  slide  down  to  create  extension  of  the  DIP  joint.  Pain  and  swelling  over  the  dorsal  PIP  joint,  tenderness  over  the  PIP  central  slip,  inability  to  extend  the  PIP,  and  possible  DIP  joint  hyperextension  are  common.  Radiographically,  a  small  bone  fragment  may  be  seen  at  the  proximal  portion  of  the  dorsal  middle  phalanx.  
SN  - 
PB  - McGraw-Hill
CY  - New York, NY
Y2  - 2024/04/19
UR  - accessmedicine.mhmedical.com/content.aspx?aid=1181041989
ER  -