Endoscopic gross anatomy findings of the thoracic air sac of the turkey.

The gross anatomy of the cranial thoracic air sacs was studied in the live turkey with a fiber-optic endoscope fitted with a video system. Thirty-five out of 39 (89.7%) of the turkeys had paired single thoracic air sacs with two ostia. The other 10.3% of the turkeys had paired cranial and caudal thoracic air sacs, each with a single ostium. The air flow pattern through the common thoracic air sac with two ostia is unknown. Furthermore, 42.3% of the turkeys with a single thoracic air sac had an invagination arising from the floor of the air sac that partially divided the single thoracic air sac creating a blind-ended sac. The blind sac formed by the invagination may trap small inhaled particulate matter.