What are the hollow organs of the body? Is the kidney hollow?
Hollow organs of the body possess lumen or cavity inside, such as stomach or urinary bladder. Kidney is definitely not a hollow organ.
Then there are organs with narrow lumen, like trachea, oesophagus and intestine. Even heart has chambers within it. In the picture below, hollow tract of rectum (end of large intestine), cavity of uterus and lumen of urinary bladder are seen:-