author(s)
OR Sathyamoorthy, R Richard Churchil and N Karunakaran

abstract
In the present study, gross anatomical structure of pelvic bone of blue and yellow macaw was analyzed. The pelvic bone of blue and yellow macaw is a large, inverted shovel shaped structure. It consists of two hip bones (ossa coxae), each of which was made up of an ilium, an ischium and a pubis. The space between the pelvic bones was occupied by rhomboid shaped lumbosacral mass. The ilium was longest (8.5 cm) and largest bone of os coxae in blue and yellow macaw. The pre-acetabular part was 4.5 cm long and 1.5 cm wide and the post-acetabular part was 4.0 cm long and 0.8 to 1.0 cm wide. The pre and post-acetabular parts of the ilium were separated by a short ridge above the level of acetabulum. The caudal end of the ilium showed a thin, elongated, straight and caudally extended caudal process, projecting ventrally. The canalis ilioneuralis was not formed. The acetabulum was formed by ilium, ischium and pubis. Caudodorsal rim of acetabulum showed the anti-trochanter, a bony prominence with sharp edges carrying a triangular facet. The ischium was roughly triangular, thick bony plate. The ventral border of the ischium below and behind the level of posterior rim of the acetabulum, showed a small oval foramina, the foramen ovale with broad caudal end. Behind this foramen, the ventral border of ischium formed synostosis with the pubis. Behind this a large Ischio-pubic Incisure was noticed. The pubis was a thin, rod-like bone which followed the ventral border of the ischium and projected beyond it caudally and bent slightly medially. The pectineal process was rudimentary.