Pelvic differences between brachycephalic and mesaticephalic cats and indirect pelvimetry assessment

Abstract

Pelvic measurements were carried out in cats with various cranial conformations to (1) determine pelvic morphometry, (2) compare any pelvic differences with cranial conformation and gender and (3) determine whether body biometrics can be used to predict pelvic measurements. Thirteen brachycephalic and 14 mesaticephalic female cats and 17 brachycephalic and nine mesaticephalic male cats were used. Body and external pelvic measurements, as well as pelvic radiographs, were performed. Brachycephalic females all had external pelvic and radiographic measurements that were significantly smaller than those of the mesaticephalic females, including smaller pelvic inlet and outlet areas and a smaller pelvic canal shape. Brachycephalic females had wider and flatter heads than do mesaticephalic females. Similarly, brachycephalic males all have radiographic pelvic measurements that are smaller than those of mesaticephalic males. Males had larger pelvis measurements than did their female counterparts for both cranial types, and indirect pelvimetry did not demonstrate good predictive value in determining the internal pelvic measurements. Thus, we conclude that pelvic differences exist between genders and between brachycephalic and mesaticephalic cats. Furthermore, body biometric measurements do not have good predictive value for determining internal pelvic measurements.

Pelvic bone structures in free-ranging Eurasian lynx (Lynx lynx) from Switzerland: a radiological pelvimetry study

“…We took each measurement three times and retained the average of the three values. Similarly to previous studies in domestic cats (5,8), we made five measurements in the left-right or right-left lateral projection (Fig 2A) and five in the ventro-dorsal projection (Fig 2B). In addition, we calculated two ratios between the height and width of the pelvis: vertical diameter/acetabula (VD/AC) and sagittal diameter/transversal diameter (SGD/TD).…”

“…We made our comparisons with studies in domestic cats (5,8) and dogs (9,10) since the applied methods were the same. Data on pelvimetry remain scarce even in domestic animals and especially in males, because studies mostly focus on the contribution of female pelvic size to rearing performance (9,11,12); however, depending on their pelvic shape, animal species can be classified as dolicopelvic, platypelvic or mesatipelvic.…”

“…In Eurasian lynx, the values of the pelvic height/width ratios (SGD/TD and VD/AC) were close to one, corresponding to a nearly circular pelvis shape or mesatipelvis for both sexes. Thus, the Eurasian lynx can be classified as a mesatipelvic species, similarly to domestic cats (8).…”

“…Currently there are no studies proving the heritability of pelvic characteristics in felids. Nevertheless, it has been demonstrated in Boston terrier dogs that 26 per cent of the offspring’s pelvic shape could be explained by the pelvic shape of the parents (5,7,8). Thus, if pelvic shape were also inherited in lynx, pelvic malformation and narrowing may occur at an increased frequency in the inbred lynx population in Switzerland.…”

“…It can be done by palpation or on x-rays. Radiographic pelvimetry is often used to calculate the pelvic size in humans, and has also been employed in domestic animals such as cats (5,8), dogs (9,10), cattle (11), sheep (12) and Indian buffaloes (13).…”