Species-dependent topography of the peritoneum

Planimetric studies of peritoneal surface area were performed in 10 humans, 12 rabbits, and 15 rats. It was found that the total peritoneal surface area (TPSA) correlated in humans with body surface area (BSA) (r = 0.98, p < 0.0001) and body weight (r = 0.93, p < 0.001), and correlated in animals with body weight (r = 0.80, p < 0.005 in rabbits; and r = 0.88, p < 0.0001 in rats). The area of parietal peritoneum was 18.1 +/- 1.8% of TPSA in humans, 17.8 +/- 1.0% of TPSA in rabbits, and 22.6 +/- 2.1% of TPSA in rats (p < 0.001 vs humans and rabbits). Additionally, the area of peritoneum covering the individual organs (expressed as % of TPSA) was different in humans, rabbits, and rats: for example, the area of peritoneum covering the diaphragm was 6.4 +/- 1.5% of TPSA in humans, which was larger than in animals (3.0 +/- 0.3% in rats, p < 0.0001 vs humans and rabbits; and only 2.1 +/- 0.4% in rabbits, p < 0.0001 vs humans). Presented results show that interspecies variation in the topography of the peritoneum should be taken into account when the results from experimental studies done on animals are extrapolated to humans.