[Sonographic diagnosis of channel pelvis]

This paper reports the findings in 22 primigravidae in whom Caesarian section was performed because of impaction of the head in mid-pelvis. 100 women who had normal deliveries served as controls. The routinely-determined external measurements of the pelvis were within the normal range in all women, whereas the distances between symphysis and the 3rd or 5th sacral vertebra were reduced in comparison with the conjugata externa in patients requiring Caesarian section. For an exact diagnosis ultrasound and X-ray pelvimetry was performed post sectionem. A reduced distance between the symphysis and the 3rd or 5th sacral vertebra was ascertained by both methods. Hence, a channel pelvis might be the main reason in these women for standstill in labour. The ultrasound and X-ray pelvimetry results were comparable.