The topography of the thoraco-abdominal viscera in the ostrich (Struthio camelus).

The topography of the thoraco-abdominal viscera in the ostrich was studied in 20 birds varying in age from 2 weeks to 12 months. The lungs occupied the dorsal third of the thorax, and the heart lay in the cranioventral thorax perpendicular to the long axis of the body. There was no pleural cavity. The liver was situated in the caudoventral part of the thorax, and the proventriculus occupied the left cranial part of the abdomen between the 7th vertebral rib and the acetabulum. The gizzard lay in the cranioventral part of the abdomen, resting on the sternum and abdominal floor. The duodenum formed a loop from right to left, with the pancreas lying between the 2 limbs of the loop. The coiled jejunum and ileum occupied the ventral part of the abdomen between the gizzard and pelvis. The two caeca lay on either side of the terminal ileum with their apices in the pelvis. The rectum was the longest part of the intestine and could be divided into a thick proximal segment situated in the right dorsal part of the abdomen, and a thin distal part that occupied the left caudodorsal part of the abdomen. The trilobed kidneys lay along the ventral surface of the synsacrum, with the adrenal glands at their cranioventral poles. The testes lay ventrally to the cranial divisions of the kidneys, whereas the left ovary was situated ventrally to the cranial division of the left kidney. The spleen lay wedged in between the right kidney, caudal vena cava and proventriculus. The thyroid glands were situated at the cranial borders of the subclavian arteries, and the thymus lay at the base of the neck.