Background: There is a scarcity of data regarding the ultrasonographic characterization of tendons and ligaments in the distal limbs of donkeys.
Aims: To determine ultrasonographic characteristics of normal tendons and ligaments at the palmar/plantar aspect of the cannon region in Egyptian donkeys.
Methods: B-mode ultrasonography was conducted for the proposed tendons and ligaments in 12 clinically normal donkeys. Targeted structures were examined using transverse and longitudinal scans and evaluated in shape, echogenicity, echogenic pattern, fiber alignment pattern, and cross-sectional area (CSA).
Results: Using transverse scan, the sonographic shapes of tendons and ligaments of metacarpal and metatarsal regions were determined. Upon examining different levels of each region, specific ligaments, not tendons, were present only at the higher levels. The echogenicity of ligaments and tendons was either similar or variable across different levels. All tendons and ligaments displayed homogeneous echogenicity except for the suspensory ligament. In the longitudinal scan, tendons maintained linear and parallel fiber alignment along examination levels. Conversely, ligaments displayed mostly inconstant fiber patterns (linear/crimp). There was a statistically significant (P<0.05) difference in CSA of tendons and ligaments between certain levels within metacarpal and metatarsal regions. Upon comparing metacarpal and metatarsal regions, there were distinct variations in some ultrasonographic characteristics of the same tendons and ligaments.
Conclusion: This study established the ultrasonographic features of normal tendons and ligaments at the palmar/plantar aspect of the cannon region in donkeys (Equus asinus). These ultrasonographic data can be a reference guide when cannon region lameness is suspected.
Keywords: Cannon region; Donkey; Ligaments; Tendons; Ultrasonography.