Morphological examination of the normal kidney and urinary bladder in goats (Capra hircus) using anatomical sections and computed tomography

Abstract

Background: Cross-sectional imaging is set to become the standard method for diagnosing various pathological conditions of the urinary tract in goats, and the concept for this atlas originated from this understanding. Until now, there has not been a comprehensive comparative atlas detailing the structures of the urinary tract in goats and their relationships with other organs.

Aim: The main aim and objective of this study was to compare anatomically frozen cross-sections and detailed computed tomography (CT) images of the urinary tract, which may be used to diagnose urinary abnormalities and affections in goats.

Methods: Eight healthy adult goats (Capra hircus) of both sexes were collected for anatomical and diagnostic examinations; average age: 15-25 ± 0.52 months and average weight: 25-35 ± 0.42 kg. The study focused on the pelvic and abdominal cavities, along with their contents and relationship with urinary organs. The examination included the analysis of bony and soft tissues using median, sagittal, and cross-anatomical sections. Subsequently, the specimens were subjected to diagnostic screening by CT.

Results: We found that both kidneys were readily distinguishable in both anatomical and CT scans as spherical to bean-shaped, but in the CT scan, the kidneys exhibited hypoechoic features with an anechoic hilus, and there was no sharp demarcation between the cortex and medulla, although the cortex was slightly denser than the medulla. In the dorsal-plane CT scan, the right ureter was positioned dorsally adjacent to the caudal vena cava, extending toward the urinary bladder. The egress of the left ureter from the left renal hilus was observed in the transverse CT image. On transverse- and dorsal plane CT, the urinary bladder may be identified at the sacrum level on the pelvic floor, located beneath the uterus and rectum. A dorsal-plane CT scan revealed the presence of the urethra exiting the urine bladder in a caudal direction.

Conclusion: The cross-sectional layout of CT images enables both students and clinicians to observe the anatomical connections and features of the goat urinary tract, which might not be easily seen through dissection alone. Furthermore, this atlas could serve as a helpful resource for study and clinical reference to enhance the understanding of goat urinary tract anatomy, which can ultimately help address pathological conditions.

Keywords: CT; Frozen cross sections; Goat; Urinary bladder; kidney.

Fig. 1.. Normal 3D CT scans of the abdomen and pelvis in healthy goats (Panels A, B) show the thoracic vertebrae (T), lumber vertebrae (L), ribs (R), pelvic bone (P), and sacrum (S).

Fig. 2.. Representative macrographic images of cross-sectional anatomy (Panel A-C) and CT image (5-mm thickness) (Panel B-D) of the goat abdomen. Panel A: 1- Twelfth thoracic vertebra; 2- Costal bony segments; 3- Right kidney; 4- Dorsal ruminal sac; 5- Ventral ruminal sac; 6- Right longitudinal ruminal pillar; 7- Jejunum; 8- Cecum; 9- Right lobe of liver; Red arrow: Renal hilus. Panel (B-C): 1- Twelfth thoracic vertebra; 2- Costal bony segments; 3- Right kidney; 4- Dorsal ruminal sac; 5- Ventral ruminal sac; 6- Greater omentum; 7- Abomasum; 8- Caudate lobe of liver; 9- Right lobe of liver; 10- Gall bladder; Red arrow: Renal hilus; yellow arrow: Right renal artery; Green arrow: Caudal vena cava; Blue arrow: Aorta. Panels (D-F): 1- Second lumbar vertebra; 2- Left kidney; 3- Dorsal ruminal sac; 4- Ventral ruminal sac; 5- Left longitudinal ruminal pillar; 6- Jejunum; 7- Cecum; 8- Colon; Blue arrow: Aorta; Yellow arrowhead: left renal artery; Red arrowhead: Left ureter.

Fig. 3.. Representative macrographic image of cross-sectional anatomy (Panel A) and computed tomography image (5-mm thickness) (Panel B) of the goat pelvis. Panel (A –B): 1- Sacrum; 2-Urinary bladder; 3- Rectum; 4-Uterus.

Fig. 4.. Representative computed tomography image of the goat trunk in the dorsal plane. Panel (A): 1-Right kidney; 2-Left kidney. Panel (B): 1-Right kidney; 2-Right renal vein; 3-Caudal vena cava; 4-Right ureter; and 5- caudate lobe of the liver. Panel (C): 1-Right kidney; 2-Aorta. Panel (D): (1) urinary bladder; (2) urethra; (3) intra-ruminal gases; (4) rumen; (5) intestinal; (6) colon.