Rabbit common calcanean tendon as an animal model: ultrasonographic anatomy and morphometry.

BACKGROUND The aim of the present study was to evaluate usefulness of ultrasonography in assessment of rabbit common calcanean tendon, to describe its ultrasonographic anatomy and to perform morphometric analysis of this structure. MATERIALS AND METHODS Fifteen skeletally-matured New Zealand rabbits were used in the study. Ultrasonographic examinations of common calcanean tendon (CCT) were performed in longitudinal and transverse planes from caudal approach. Sagittal diameters of superficial digital flexor tendon and CCT were measured on longitudinal scans. Sagittal and transverse diameter, cross-sectional area and perimeter of the CCT were assessed on transverse scans. Statistical analysis was performed using StatisticaPL software (StatSoft®, Poland). RESULTS In longitudinal images structure of CCT was clearly visualised. Its superficial hypoechoic part corresponds to superficial digital flexor tendon and deeper hyperechoic to gastrocnemius tendon. In transverse images cross-sectional area presented varied echotexture. Proximally, CCT was rounded in transverse section and became slightly wider and flattered distally. Statistical analysis showed no differences between results obtained from right and left hindlimb (p > 0.05). Measurements of sagittal diameter of CCT obtained in transverse planes were significantly higher than sagittal diameter measurements obtained in longitudinal plane in corresponding locations (p < 0.001). All performed measurements showed a growing trend with the increasing distance from the calcaneal tuber. CONCLUSIONS Ultrasonography is suitable technique for assessment of CCT in a rabbit model and provides satisfactory images for morphometrical evaluation.