Human liver umbilical fissure variants: pons hepatis (ligamentum teres tunnel).

PURPOSE: In the classical description of normal liver anatomy, the umbilical fissure is a long, narrow groove that receives the ligamentum teres hepatis. The pons hepatis is an anatomic variant, where the umbilical fissure is converted into a tunnel by an overlying bridge of liver parenchyma. We carried out a study to evaluate the existing variations of the umbilical fissure in a Caribbean population. METHODS: We observed all consecutive autopsies performed at a facility in Jamaica and selected cadavers with a pons hepatis for detailed study. A pons hepatis was considered present when the umbilical fissure was covered by hepatic parenchyma. We recognized two variants: an open-type (incomplete) pons hepatis in which the umbilical fissure was incompletely covered by parenchyma ≤ 2 cm in length and a closed type (complete) pons hepatis in which the umbilical fissure was covered by a parenchymal bridge > 2 cm and thus converted into a tunnel. We measured the length (distance from transverse fissure to anterior margin of the parenchymatous bridge), width (extension across the umbilical fissure in a coronal plane) and thickness (distance from the visceral surface to the hepatic surface measured at the mid-point of the parenchymal bridge in a sagittal plane) of each pons hepatis. A systematic literature review was also performed to retrieve data from relevant studies. The raw data from these retrieved studies was used to calculate the global point prevalence of pons hepatis and compared the prevalence in our population. RESULTS: Of 66 autopsies observed, a pons hepatis was present in 27 (40.9%) cadavers. There were 15 complete variants, with a mean length of 34.66 mm, mean width of 16.98 mm and mean thickness of 10.98 mm. There were 12 incomplete variants, with a mean length of 17.02 mm, width of 17.03 mm and thickness of 9.56 mm. The global point prevalence of the pons hepatis (190/5515) was calculated to be or 3.45% of the global population. CONCLUSIONS: We have proposed a classification of the pons hepatis that is reproducible and clinically relevant. This allowed us to identify a high prevalence of pons hepatis (41%) in this Afro-Caribbean population that is significantly greater than the global prevalence (3.45%; P < 0.0001).

Accessory Inferior Sulci of the Liver in an Afro-Caribbean Population.

INTRODUCTION: There have been no previous reports on the anatomic variations that exist on inferior surface of the liver in Caribbean populations. This information is important to optimize radiology and hepatobiliary surgical services in the region. METHODS: Two investigators independently observed 69 cadaveric dissections over five years and described the variations in surface anatomy. RESULTS: In this population 88% of cadaveric livers had conventional hepatic surface anatomy. However, 12% had accessory sulci present on the visceral surface of the liver, with a 7:1 male preponderance. When present, there was 100% correlation between the presence of Rouvière's sulcus and the right branch of portal pedicle. CONCLUSION: Abnormal surface anatomy is present in 12% of unselected specimens in this Caribbean population. Interventional radiologists and hepatobiliary surgeons practicing in the Caribbean must be cognizant of these differences in order to minimize morbidity during invasive procedures.