Morphometric description of the feline radius and ulna generated from computed tomography

Objectives: This study aimed to describe the length, internal and external diameters, cancellous bone volume and extent, and cortical thickness at predetermined locations in the radius and ulna of a cohort of skeletally mature, disease-free feline cadavers using radiography and computed tomography (CT). Methods: Five feline cadavers were used (mean weight 3.31 kg, range 2.55–4.24 kg). Antebrachii (n = 10) were radiographed to confirm skeletal maturity and normal radiographic appearance prior to CT. Reconstructed CT images were used to measure bone length, cortical thickness, internal and external diameters, and cancellous extent. Cancellous bone volume was calculated automatically using OsiriX after manual segmentation (350–850 Hounsfield units window) from axial CT slices. Results: CT images were used to measure bone length, cortical thickness, internal and external diameters, and cancellous extent and volume. Mean radial length was 95.89 mm (95% confidence interval [CI] 88.52–103.26 mm) and mean ulna length was 114.67 mm (95% CI 105.53–123.81 mm). The olecranon had the largest mean cancellous bone volume (94.16 mm3; 95% CI 72.09–116.23 mm3) and it extended a mean of 13.12 mm (95% CI 11.73–14.51 mm) distally. The radius at the level of the trochlea and the ulna at the level of the coronoid processes had the largest external diameters, respectively. The medullary canal narrowed at the level of the coronoid processes and became cranially eccentric at the proximal third of the diaphysis. The cranial cortex at the level of the coronoid processes and the caudal cortex of the olecranon were markedly thicker than other cortices at those levels. Conclusions and relevance: Morphometry of the feline antebrachium was described using CT, and should be a useful reference for future research investigations and clinical applications