Transverse diameter

The transverse diameter is a pelvic measurement used to assess the anatomy of the pelvic area, particularly in the context of parturition, obstructive dystocia and constipation. It is determined from a ventrodorsal radiograph or multiplanar reconstructed CT images of the pelvis.

The transverse diameter is the greatest diameter of the pelvic inlet, i.e. the greatest distance separating the arcuate lines of the ilium, perpendicular to the sagittal plane.

The following values have been published in the literature for the transverse diameter:

• Boston terrier with normal parturition (7.5 +/- 1.1 kg) and dystocia (7.5 +/- 0.8 kg): 4.3 +/- 0.08 cm - 4.2 +/- 0.10 cm respectively

• Scottish terrier with normal parturition (9.5 +/- 0.9 kg) and dystocia (9.8 +/- 0.8 kg): 4.3 +/- 0.06 cm - 4.3 +/- 0.04 cm respectively

• English bulldogs with normal parturition (21.25 +/- 0.91 kg) and and caesarean delivery (25.16 +/- 1.44 kg) : 5.05 +/- 1.15 cm - 5.31 +/- 0.21 cm respectively

• English bulldogs (range 18.1 to 30.8 kg, mean 23.56 kg) from both genders : 5.0 +/- 0.3 cm

• Non-brachycephalic dogs of various breeds and crossbred dogs (range 18 to 31.1 kg, mean 26.62 kg) from both genders (18-30 kg) : 5.5 +/- 0.4 cm