Observations of different types of sacra in Greyhounds based on the occurrence of sacrocaudal fusion

Little attention has been paid to the normal fusion of the vertebrae of greyhounds despite the common occurrence of sacrocaudal fusion. The current study aimed to investigate and provide data on the morphology of different types of fused sacra (B, C and D) in greyhounds and also to determine the potential association between the sex, body mass and morphology of fused sacra (S. Weight, S. Length and S. Width) in greyhounds. The sacra were collected from 171 greyhounds from Melbourne, Australia. After classifying the sacra based on the occurrence and types of the sacrocaudal fusion, they were measured for weight of the sacrum, length of sacrum and the width of sacrum. Multiple linear regression analyses were used to quantify the association between weight of the sacrum (as the outcome variable) type of sacrum (A, B, C and D), body mass and sex (as explanatory variables). The results proved that there are measurable differences between each type of fused sacra (B, C and D) and the standard sacra (A). In addition, this study showed that sex or body mass do not influence the occurrence of different types of fusion. The results of this study showed that the occurrence of sacrocaudal fusions was independent of body size in this population of greyhounds. Sacrocaudal fusion might affect the biomechanics in greyhounds independently of effects of body size.

Structural anatomy and morphometric analyses of sacra in greyhounds

This study was conducted to provide structural and morphological data on the sacra of greyhounds. Descriptive quantitative investigation was carried out on 171 sacra of greyhound`s cadavers and then classified into standard and fused sacra based on the number of fused sacral vertebrae. The weight, length and width of sacrum of sacra were measured. Both standard (59%) and fused sacra (41%) were identified. The average length and width of the standard sacrum were found to be 46.14 ± 2.53 mm and 57.89 ± 3.54 mm, respectively. The sacral length was 1.61-mm longer in males (p < .01), and the sacral width was 0.46-mm shorter in males but not significant (p = .51). The average weight of a standard sacrum was 26.54 ± 4.55 g and was 1.18 g heavier in males but not statistically significant (p = .24). Results showed that one-kilogram increase in the body mass was associated with a 0.3 mm (p < .001) increase in sacral length, and a 0.54 mm (p < .001) increase in sacral width, respectively. The morphological data of the standard and fused sacra provided in this study might help the veterinary community to improve treatment and rehabilitation and help the trainer to design the right training protocol for racing greyhounds. In addition, the results of this study are a step to understand the sacrum's functions and how the greyhound's body functions and future studies are required to investigate the biological importance of these findings.

Variation in the seventh lumbar vertebra and the lumbosacral junction morphometry associated with the sacrocaudal fusion in greyhounds

The lumbosacral joint is where the 7th lumbar vertebra (L.7) articulates within the sacrum. It is a clinically important area in the dog because of its relatively large range of motion. The current study aims to determine the possible differences in the length of the L.7 vertebra and the angle of the lumbosacral junction among greyhounds of standard and those of fused sacra, and to determine the potential association of sex, body mass and type of fused sacrum (standard and fused) on the morphology of the L.7 vertebra and the angle of the lumbosacral junction. Radiographs of 55 greyhound cadavers were used for radiographing; all radiographic images were stored and measured using X-ray acquisition software, and then analysed using descriptive statistics, multiple linear regression and logistic regression. The results of this study showed a significant increase (p < .008) in the length of the L.7 vertebra and the angle of the lumbosacral junction (p < .028) in greyhounds with fused sacra comparing with those of standard sacra, but the L.6 length was not significant (p = .431). Differences have been found in the length of L.7 vertebra and the angle of the lumbosacral junction in greyhounds. It was found that in greyhounds, any variation in the sacrum's anatomical features may alter the structure of the surrounding anatomical structures such as the L.7 vertebra and lumbosacral junction.