A comparative study of breed differences in the anatomical configuration of the equine vertebral column

Abstract

The importance of the equine thoracolumbar vertebral column in orthopaedic disorders is well recognized and diagnostic imaging becomes more feasible, but little is known about variations in the anatomical configuration within breeds. In this descriptive post‐mortem study, anatomical variations in three widely differing breeds: Warmblood horses, Shetland ponies and semi‐feral Konik horses are described. The caudal cervical (C), thoracic (T), lumbar (L) and sacral (S) regions of the vertebral column of 30 Warmblood horses, 29 Shetland ponies and 18 Konik horses were examined using computed tomography and visualized by volume rendering. Homologous/morphologic variations in the caudal cervical area were frequently seen in Warmblood horses (43%), which was significantly more than in the other breeds (p < 0.001). The as standard described equine formula of 18 T, 6 L and 5 S vertebrae was seen in 78% of Konik horses, but only in 53% Warmblood horses and 38% Shetland ponies, which was significantly different (p < 0.05). Overall, Shetland ponies showed a higher tendency of thoracoization, lumbarization and more variations in the number of vertebrae and pairs of ribs. Ankylosed intertransverse joints (ITJs) between transverse processes of the lumbar vertebrae were most common between the second last and last lumbar vertebra and prevalence was significantly higher in Shetland ponies (61%), than in Warmblood horses (38%) and Konik horses (7%) (p < 0.0001). Cranial to the second last lumbar vertebra there were fewer ITJs ankylosed (14%) in Warmblood horses (p < 0.0095), and this decrease in number of ankylosed ITJs was different compared to the change in ankylosed ITJs in Shetland ponies (p < 0.005). ITJs occurred asymmetrically in 15% (12/77) of the cases. A limitation of the study was that clinical data of the horses were only incompletely available, precluding any conclusions about the potential clinical implications of anatomical variations. Knowledge of variation in osseous anatomy of the equine thoracolumbar vertebral column is important for the interpretation of diagnostic imaging. To assess the functional importance and clinical relevance of this variation, follow‐up studies are necessary.

Morphological importance of coronary ostia in sheep and swine

“…Blood flow to the myocardium may be affected by different positions of the CO. Recent studies have described the influence of breed as a factor of anatomical variation in purebred animals (Abril‐Parreño et al., 2021; Spoormakers et al., 2021). However, when the morphological patterns of some organs are analysed in crossbred animals, this interaction becomes difficult.…”

“…by different positions of the CO. Recent studies have described the influence of breed as a factor of anatomical variation in purebred animals(Abril-Parreño et al, 2021;Spoormakers et al, 2021).…”

Truly dorsostable runners: Vertebral mobility in rhinoceroses, tapirs, and horses

“…Both Paleogene equoids mentioned are characterized by the vertebral formula 7C + 17T + 7L. The common vertebral formula of extant equids is 7C + 18T + 6L with relatively frequent deviation 7C + 18T + 5L and relatively rare deviations 7C + 17T + 6L, 7C + 17T + 7L, 7C + 18T + 7L, 7C + 19T + 5L, and 7C + 19T + 6L (Spoormakers et al, 2021; Table S1 herein). Extant rhinoceroses and tapirs are characterized by a further increased number of thoracic vertebrae (18–20 and 18–19, respectively) at the expense of a reduced number of lumbar vertebrae.…”

Ultrasonography, Microcomputed Tomography, and Macroscopic Preparation in an Anatomical Study of the Thoracic Limb of the Golden-Headed Lion Tamarin (Leontopithecus chrysomelas)

“…Threedimensional computer models, simulations of biomechanics of movement, and series of images from different cross-sections make it possible to present anatomy in a wide range of non-invasive ways. CT is often used to analyse the skeletal system [11,12], whereas ultrasonography is used for soft tissues such as muscles [13][14][15][16]. However, many authors of anatomical studies still use traditional methods, which involve the preparation of dead tissues [17,18].…”