As part of the spine, the vertebral canal represents a central structure protecting the spinal cord running within it. Since alterations to the spinal canal and adjacent structures can have a significant impact on the spinal cord, knowledge of the physiological vertebral canal dimensions is essential. Compression of spinal nerves at the lumbosacral junction is the primary cause of cauda equina syndrome (CES). Although CES is common in dogs, it is rarely documented in cats. Given the lack of information on normal vertebral canal dimensions in cats, it is necessary to collect data and verify currently used measurements, to determine if and to what extent comparisons with dogs are valid. In 50 cats, interpedicular (ID) and midsagittal (SD) diameters were examined from the first thoracic (Th1) to the first sacral vertebra (S1). In 28 of these animals, the intervertebral disc width (IVDW) was measured. All data were gathered through gross anatomical dissection of the cats. Significant lumen reduction was evident in all cats from L6 to S1 with the narrowest point at S1. Narrowings were also found in the thoracic spine. The widest points coincide with the spinal cord enlargements. IVDW shows relatively constant values up to Th10–Th11 and peaks at L7–S1 in 95.65% of cats. While distinct similarities to dogs were observed, differences exist. The findings allow conclusions as to whether relations between the parameters and resulting predispositions to pathological changes can be derived. This could help the understanding of the pathogenesis of feline spinal diseases, particularly compressive myelopathies. Further studies are necessary to investigate the impact of age, sex and breed.

The vertebral canal plays a critical role in protecting the spinal cord and maintaining biomechanical stability. Although the vertebral canal has been extensively studied in dogs, equivalent analyses in cats are limited. This study provides a comprehensive morphological and morphometric assessment of the feline vertebral canal from atlas (C1) to sacrum (Sc) using computed tomography (CT). In 35 cats, predominantly European Shorthairs, cross-sectional area (CSA) and perimeter (P) were determined at cranial, central, and caudal levels of each vertebra. Vertebral canal circularity (CVC) was calculated to characterize shape and intersegmental angles (ISA) were measured to quantify spinal curvatures. Additionally, sex- and age-related differences were examined. Male cats exhibited significantly larger CSA and P than females, whereas CVC was mostly unaffected by sex. CVC was highest at C3 (cervical), Th6 (thoracic) and L4 (lumbar) and lowest at C1, Th1, Th13/L1 and the sacrum, reflecting shape variations at spinal transition zones. CSA and P were strongly correlated. Cats older than 10 years showed increased CSA and P compared with younger individuals, accompanied by decreased CVC at multiple levels, suggesting age-related remodeling. ISA largely corresponded with physiological spinal curvatures described in the literature. This study presents the first CT-based morphological and morphometric characterization of the feline vertebral canal spanning C1 to Sc. The data provide fundamental reference values for diagnostic imaging and comparative anatomy, suggesting vertebral canal shape, besides its dimensions, as a potential factor in the context of feline spinal pathology.