Doppler Ultrasonographic Study of the Spleen in Live Post Natal Goats

The spleen is a secondary lymphoid organ of anatomic and functional component of reticuloendothelial system. The normal gross anatomical observations made in the embalmed or exsanguinated goats revealed that the spleen extended between 11^th intercostal space to 13^th rib in the first year of post-natal age whereas it extended between 9^th rib to 13^th rib during one to two years of post-natal age after which it extended beyond the last rib (13^th rib) in the lumbo-costal angle. Therefore parietal surface of in-situ fixed adult spleen showed impressions of last four ribs. The ultrasonographic observations of spleen in live goats at different age groups were done using a convex probe 2.5 to 5 MHz Colour Doppler Mylab onevet (e-saote) German Ultrasound Scanner. The gross anatomy of location and extent of spleen were observed using USG. The study revealed differences from the usual gross anatomical observations made in the embalmed or exsanguinated goats. 

Apparently healthy goats with clear records of age from the Instructional Livestock Farm Complex (ILFC), Veterinary College and Research Institute, Namakkal were prepared for ultrasonographic study. One goat from each age groups (8 months, 14 months, 20 months, 26 months, 32 months, 39 months and 45 months) under study, thereby seven goats at different ages were prepared by shaving the skin on their left costal wall of the abdomen and flank. Goats were subjected to ultrasound study using a convex probe 2.5 to 5 MHz Colour Doppler Mylab onevet (e-saote) German Ultrasound Scanner. Ultrasonography was performed and the results were interpreted by the expert team in Veterinary Clinical Complex (VCC), Veterinary College and Research Institute, Namakkal.

The convex probe of the ultra sound scanner was applied on the left abdominal wall and the margins of the spleen were visualized at 8^th, 9^th, 10^th, 12^th intercostal spaces and immediately caudal to the last rib. Dorsally the parietal surface of spleen was in direct contact with the pulmonary diaphragm while the ventral visceral surface lay over the cranial part of dorsal sac of the rumen (Fig 4). Similar observations were noticed by Acorda et al., (2009) who recorded the ultrasound features of spleen in one to three year old goats using a 3.5 MHz convex-array transducer. Whereas, the normal gross anatomical observations made in the embalmed or exsanguinated goats revealed that the spleen extended between 11^th intercostal space to 13^th rib in the first year of post-natal age whereas it extended between 9^th rib to 13^th rib during one to two years of post-natal age after which it extended beyond the last rib (13^th rib) in the lumbo-costal angle. Therefore parietal surface of in-situ fixed adult spleen showed impressions of last four ribs.
 

       
The capsule was highly echogenic while the parenchyma consisted of numerous weak echoes distributed homogenously. The splenic vessels were anechoic with hyperechoic walls and appeared as longitudinal or cross sections (Fig 3). Similar observations were noticed by Braun et al., (2013) in goats.
 

       
The greatest length was found at 11^th intercostal space (Fig 1) during the post-natal age of three to eight months which was about 6 cm. The greatest length was found at 10^th intercostal space during the post-natal age of eight to twelve months which was about 7 cm (Fig 4). The greatest length was found at 9^th intercostal space during the post-natal age above one year (Fig 2) which was about 9 to 15 cm. During the post-natal age above one year the smallest length was found to be behind the last rib which was about 4 cm in adult goats. The ultrasonographic appearance and location of the spleen in thirty number of female Saanen goats were described by Braun and Steininger (2010) who scanned the intercostal spaces of left thoracic wall with a real-time ultrasound machine (Hitachi EUB 8500) with a 5.0 MHz linear transducer in standing goats. The margins of the spleen were visualized at 8^th, 9^th, 10^th, 12^th intercostals spaces and immediately caudal to the last rib. They revealed that the greatest length was found at 8^th intercostal space which was about 20 cm and the smallest length was found to be behind the last rib which was about 7 cm in adult goats.
 

 

The spleen in goats showed greatest length at 11^th intercostal space during the post-natal age of six months which was about 6 cm. The greatest length was found at 10^th intercostal space during the post-natal age of twelve months which was about 7 cm. The greatest length was found at 9^th intercostal space during the post-natal age above one year which was about 9 to 15 cm. During the post-natal age above one year the smallest length was found to be behind the last rib which was about 4 cm in adult goats. The gross anatomy of spleen in exsanguinated, embalmed or slaughtered goats revealed that the posterior extent was at 12^th intercostals space. But when studied using ultrasound in live goats, the posterior end of spleen extended beyond the last rib which may be attributed to the storage of blood in the organ.