What's the noun for abdomens? Here's the word you're looking for.
abdomen
(obsolete) The fat surrounding the belly. [Attested from the mid 16th century until the late 17th century.]
(anatomy) The belly, or that part of the body between the thorax and the pelvis, not including the back; or in some lower vertebrates, the portion between the cardiac and caudal regions. [First attested in the early 17th century.]
(anatomy) The cavity of the belly, which is lined by the peritoneum, and contains the viscera; often restricted in humans to the part between the diaphragm and the commencement of the pelvis, the remainder being called the pelvic cavity. [First attested in the early 17th century.]
(zoology, entomology) The posterior section of the body, behind the thorax, in insects, crustaceans, and other Arthropoda. [First attested in the late 18th century.]
“An abdominocentesis was not performed due to the risk of perforating the abdominal mass.”
“The fluid appeared homogeneous and anechoic, and abdominocentesis yielded clear yellow fluid that smelled of urine.”
“In most cases, uroperitoneum can be diagnosed based on the results of ultrasonography and abdominocentesis and calculation of the peritoneal-to-serum creatinine concentration ratio.”