An anatomical study of the respiratory air sacs in ostriches

An accurate description of the number, location and relative position of th e air sacs and their diverticula in the ostrich is essential for a better u nderstanding of the pathogenesis of air sacculitis in this bird. The air sa cs were studied in ten ostriches of varying ages by latex or silicone casti ng of the respiratory tract and dissection. Results revealed that the air s acs of the ostrich conform to the general pattern in birds. Cervical, later al and medial clavicular, cranial and caudal thoracic, and abdominal air sa cs are present. The left and right medial clavicular air sacs fuse with eac h other ventrally to the trachea to form a single, median compartment. A un ique, large gastric diverticulum which covers the caudal aspects of the pro ventriculus and gizzard originates from the median compartment of the clavi cular air sac. The lateral clavicular air sacs and their diverticula are si milar to those of other bird species, with the exception that humeral diver ticula are absent. Both abdominal air sacs are relatively small, with the l eft sac being the larger. Perirenal and femoral diverticula, similar to tho se found in other bird species, are present. However, the entire femur is a erated by the femoral diverticulum which also forms a large, subcutaneous d ivision caudally and caudo-laterally to the femur. The presence of this sub cutaneous part has practical implications for injury and intramuscular inje ctions. The number and location of ostia connecting the air sacs to the bro nchial tree are generally similar to those reported in other bird species.