Comparison of the Gallbladder Fossa in Livers from Cadavers with and without Gallbladders

Abstract

In humans, the gallbladder normally lies, at least partially, within the gallbladder fossa, a depression located on the visceral surface of the liver, between the right anatomical lobe of the liver and the quadrate liver lobe. During routine cadaveric dissections, we noted that livers from cadavers without gallbladders appeared to have less distinct gallbladder fossae than did livers where gallbladders were present.The purpose of the present study was to test the hypothesis that the volume of the gallbladder fossa is greater in livers when a gallbladder is present than in livers without gallbladders.To test this hypothesis, livers with their associated gallbladder were removed from cadavers and the visceral surface of each sample was observed to determine whether or not a gallbladder was present. After photographing all livers and removing gallbladders, if present, the volume of the irregularly‐shaped gallbladder fossa was determined from a mold of the fossa. To make this mold, an insulating foam sealant (Dow, Midland, MI, USA) was instilled into the area of the fossa. After foam expansion was complete, the material was trimmed flush with the surrounding liver parenchyma. This mold then was removed from the fossa and allowed to air‐dry. The volume of the gallbladder fossa was calculated by dividing the weight of the mold by the density of the foam material. Additionally, the dimensions of each fossa were estimated using an electronic digital caliper (VWR, Radnor, PA, USA) to measure the largest distance for the depth, length, and width of each mold. Statistical analyses were performed using R. Comparison of group means utilized Welch’s t‐test and the Pearson product‐moment correlation coefficient was used for correlation analyses.Livers were obtained from 34 cadavers (19 females, 15 males) with a mean age of 84.1 ± 10.8 yrs (range of 60–105 yrs). There were 8 cadavers without gallbladders (6 females, 2 males, mean age of 83.9 ± 6.6 yrs), and 26 cadavers with gallbladders (13 females, 13 males, mean age of 84.2 ± 11.9 yrs). The mean volume of gallbladder fossae from livers with gallbladders (31.01 ± 17.82 ml) was significantly greater than fossae in livers without gallbladders (8.75 ± 4.72 ml) (p=2.3 e‐06). All three measurements taken of the fossae molds (depth, length, and width) were significantly larger in the “with gallbladder livers” (p<0.05), with the largest percent difference being between the depth of the fossae – mean depth of the fossae mold from livers with a gallbladder was 20.69 ± 6.17 mm versus fossae without gallbladders having a mean depth of 7.60 ± 2.57 mm (p=1.77e‐09). When comparing the volume of fossae to the depth, length, and width of the molds, the correlation was strongest between the volume and the depth of the fossae (r=0.838, p=6.1e‐10).In conclusion, the mean volume of the gallbladder fossa was significantly greater for livers in which a gallbladder was present than in livers lacking gallbladders, with the greatest relative change in the fossae dimensions, after gallbladder removal, occurring with the depth of the fossae. The mechanism behind this change can only be hypothesized, but may be due to proliferation of liver tissue when mechanical pressure from a gallbladder is relieved by organ removal.Support or Funding InformationNone.