Abstract:
An accurate description of the number, location and relative position of the air sacs and their diverticula
in the ostrich is essential for a better understanding of the pathogenesis of air sacculitis in this
bird. The air sacs were studied in ten ostriches of varying ages by latex or silicone casting of the respiratory
tract and dissection. Results revealed that the air sacs of the ostrich conform to the general
pattern in birds. Cervical , lateral and medial clavicular, cranial and caudal thoracic, and abdominal
air sacs are present. The left and right medial clavicular air sacs fuse with each other ventrally to the
trachea to form a single, median compartment. A unique, large gastric diverticulum which covers the
caudal aspects of the proventriculus and gizzard originates from the median compartment of the clavicular
air sac. The lateral clavicular air sacs and their diverticula are similar to those of other bird
species, with the exception that humeral diverticula are absent. Both abdominal air sacs are relatively
small, with the left sac being the larger. Perirenal and femoral diverticula, similar to those found in
other bird species, are present. However, the entire femur is aerated by the femoral diverticulum which
also forms a large, subcutaneous division caudally and caudo-Iaterally to the femur. The presence of
this subcutaneous part has practical implications for injury and intramuscular injections. The number
and location of ostia connecting the air sacs to the bronchial tree are generally similar to those reported
in other bird species.
