title: Delivery of the posterior arm reduces shoulder dimensions in shoulder dystocia.
abstract: OBJECTIVE
  To evaluate a possible reduction in shoulder diameter and circumference by extending the posterior arm during delivery, for an easier birth in cases of shoulder dystocia.
  
  
  METHODS
  In this study of 33 neonates the bisacromial diameter and axilloacromial circumference were measured within 72 h of birth, first with the neonate's arms by its chest and then with 1 arm extended above its head. Reductions in diameter and circumference were evaluated.
  
  
  RESULTS
  The mean +/- SD differences in bisacromial diameter and axilloacromial circumference were 1.9 +/- 0.69 cm and 2.52 +/- 1.18 cm, respectively. A greater reduction was observed in neonates with a greater shoulder diameter.
  
  
  CONCLUSIONS
  In cases of shoulder dystocia, delivery of the posterior arm should significantly reduce shoulder dimensions, especially in larger fetuses, and prevent a need for excessive traction.
authors: Department of Obstetrics and Gynaecology, St. George's University of London, London, UK.
authors: J
authors: J
authors: Kung
authors: A V
authors: AV
authors: Swan
authors: S
authors: S
authors: Arulkumaran