Bandl ring

A Bandl ring may be seen during imaging of a patient in labor.


It is considered to be an uncommon finding in modern obstetrics (0.01-1.26%).


It is a pathologic retraction ring at "Barnes boundary line", which separates the upper contractile portion of the uterus from lower uterine segment. The constriction prevents the fetus from orienting toward the cervical os and obstructs normal labor.

Radiographic features

Ultrasound and MRI
  • uterine constriction at the junction of the thinned lower uterine segment with a thickened, retracted upper uterine segment

Treatment and prognosis

May necessitate cesarean section to avoid potential uterine rupture.

History and etymology

Named after L Bandl, a Viennese obstetrician.

Differential diagnosis