Related Experiment Video
Updated: Aug 8, 2026
Reverse Total Shoulder Arthroplasty
Published on: July 5, 2011
Delivery of the posterior arm reduces shoulder dimensions in shoulder dystocia
J Kung1, A V Swan, S Arulkumaran
1Department of Obstetrics and Gynaecology, St. George's University of London, London, UK.
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.
Conclusion:
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.
