CT Anatomy and Gross Anatomical Study of the Scleral Ring in the Common Buzzard (Buteo buteo)

Abstract

The avian scleral ring is a critical structure for ocular biomechanics and taxonomic studies, yet its morphology in raptors remains understudied. This study investigated the scleral ring in the common buzzard (Buteo buteo) using a multimodal approach: CT, micro-CT, radiography, and anatomical dissection. Analysis of five adult specimens revealed a semi-hyperbolic ring composed of 15 quadrilateral ossicles arranged in a Type B pattern (one plus and one minus excellent ossicle), with a mean anterior-posterior to width ratio of 1.32. Micro-CT imaging showed that 53.36%±1.89 of each ossicle’s volume was compact bone, suggesting biomechanical reinforcement against flight-induced stresses. The ring exhibited complete anatomical independence from adjacent cranial bones (frontal, jugal, lacrimal) and perfect bilateral symmetry (p>0.05). High-resolution micro-CT scans resolved microscopic articular interfaces and trabecular architecture non-destructively, validating its utility for delicate orbital studies. These findings provide morphometric benchmarks for comparative anatomy in Accipitriformes, demonstrate the efficacy of non-invasive imaging for species differentiation, and offer diagnostic criteria for ocular trauma management. By integrating macroscopic dissection with advanced tomography, this work establishes a framework for evolutionary, clinical, and conservation-focused studies of avian visual systems.