Traditional descriptions of liver anatomy refer to a smooth, convex surface contacting the diaphragm. Surface depressions are recognized anatomic variants. There are many theories to explain the cause of the depressions. We discuss the theory that these are caused by hypertrophic muscular bands in the diaphragm.

Variations of the liver in the form of accessory lobes account for about less than 1%. One of the commonest accessory lobes on the right is Riedel's lobe. An occasional anatomical variant of the left lobe is the beaver tail variant. Both variants are reported to be common in females. We hereby report two cases. A 45-year-old female cadaver was noticed to have Riedel's lobe and beaver tail variant. Riedel's lobe appeared to be a tongue-like projection from the right inferior margin of the liver, almost reaching the level of the iliac crest. It was partially separated from the rest of the liver by a deep fissure. The left lobe was elongated, crossed the midline, and reached the left wall of the abdominal cavity after encircling the spleen. Splenomegaly was noticed, and the left lobe of the liver had a splenic impression. Riedel's lobe was drained by the middle hepatic vein (MHV) and supplied by the right branch of the portal vein (RPV). A similar variation of the beaver tail variant was noticed in an 85-year-old female cadaver. The left lobe of the liver crossed the midline and was related superior to the spleen. The right lobe of the liver and the spleen were normal. The beaver tail variant was drained by the left hepatic vein (LHV) and supplied by the left branch of the portal vein (LPV). These variations are prone to injuries and can be confused with the abdominal mass and could interfere with laparoscopic procedures.

Introduction The liver is the largest gland in the body and shows wide variation in surface features. Knowledge of external features is essential for radiological investigations and during abdominal surgeries. Morphological variation of the liver should be considered for better patient outcomes. Segmental anatomy has received more attention for segmental resection and transplant surgery. The present study aimed to determine variations in external features of the liver and indicate its clinical importance. Materials and method A cross-sectional observational study was conducted on 52 specimens of human cadaveric livers, obtained during routine dissection in the anatomy departments of various medical colleges of Gujarat, India. Livers were examined for their morphology (lobes, notches, fissures, grooves), including their variations; pictures were taken; and results were tabulated. Result In the present study, 28 (53.84%) livers were normal in appearance in reference to surfaces, borders, lobes, and fissures. Specifically, 3.84% of livers were found with a very small left lobe, and 1.92% of livers with a large saddle-shaped left lobe. Five (9.61%) livers show the presence of Riedel's lobe, three (5.76%) livers show deep renal impression, and 13 (25%) livers show grooves on its antero-superior surface. One or two extra fissures were present in 28 livers, either present on the visceral surface of the right lobe, between the caudate process and papillary process of the caudate lobe or quadrate lobe. Pons hepatis was found in 10 (19.22%) livers. Tongue-like projection of the right lobe of the liver was observed in five (9.61%) livers, while an elongated left lobe was observed in three (5.76%) livers. Conclusion Livers show wide variations in their surface features. The variations observed in the present study will be of great help to anatomists, radiologists, and surgeons during diagnosis or surgical procedures.

Liver is divided into four anatomical lobes presenting minor fissures and invisible major fissures. The prevalence of Accessory Fissures in liver ranges widely from 6 to 94%. The morphometric analysis of individual lobes is also scarce in literature. There have been instances where the surgeon has experienced some of these variations as a surprise during surgery as the existing data on the surface variations of liver is still contradictory. A sound knowledge of these variations would aid the surgeons and radiologists to circumvent the misdiagnosis and complications during surgeries.

The study was conducted in 93 cadaveric livers. Minor liver fissures, Accessory fissures and lobes were noted and measured. The livers were classified according to the Netter's classification. The morphology of caudate and quadrate lobes was studied. Any other variations in the appearance of groove for Inferior vena cava, gall bladder and its fossa were also studied. The results are tabulated.

The study revealed several variations in the morphological features of liver. Accessory fissures were noted in 51.61% of livers, distributed on various liver surfaces. Accessory lobes were noted in 27.9%. Pons hepatis was present in 22.5%. Gall bladder variations that were noted include the Hartmann's pouch (n = 14; 15.05%) and the Phrygian cap (n = 2; 2.15%). 65.6% livers (n = 61) had the sulcus of the caudate process or fissure of Gans or Rouviere sulcus which is a normal fissure present in majority of normal healthy livers.

The current study provides a complete understanding and a thorough knowledge of surface morphological variations in liver. We hope that this will be greatly helpful for surgeons and radiologists to avoid possible errors in interpretations, to plan appropriately and assist during liver surgeries and to do radiological interventions.

Background In the classic descriptions of the human liver, the umbilical fissure (UF) is a long, narrow groove on the visceral surface that receives the ligamentum teres hepatis. In this study, we document the UF variations encountered in a series of cadaveric dissections. Methods We reported UF variations using the following classification: Type I refers to "normal" anatomy where there is a long, narrow groove. In type II, the UF was covered by a fibrotic band devoid of hepatic parenchyma. In type III variants, an extension of hepatic parenchyma partially covered but did not obliterate the UF. In type IV variants, the hepatic parenchyma formed a bridge over the UF, completely obliterating the groove. After institutional review board approval, we observed all consecutive cadaveric dissections over five years and recorded the characteristics and dimensions of each UF and its immediate relations. Results There were 69 cadavers, and variant UFs were present in 38 (55.1%) cadavers: type II (1.5%), type III (20.3%), and type IV (33.3%). Conclusions In this Jamaican population, only 44.9% of persons had conventional "normal" anatomy and 55.1% had UF variants. These variants are clinically significant, as they lead to misinterpretation of patient imaging and can hinder operative procedures on the liver.

Hepatobilliary surgery is nowadays increasingly done throughout the world with advent of newer liver imaging modalities. Considering recent interest for accurate interpretation of different radiological images and performing surgical procedures, a precise understanding of hepatic surface anatomy is challenging due to high prevalence of previously identified morphological variations. Accordingly, a cadaveric study was attempted to revisit the morphological details of liver updating the unusual configurations along with their clinico-anatomical correlations and thus, compare the analysis of present study with previous published data.

We studied 110 formalin-fixed adult cadaveric livers of unknown age and sex having no pathological lesion or damage.

More than one morphological variation in combination was observed on repeated occasions in same liver specimen. The anatomical classification based on Netter's criteria was chosen in order to be coherent with previous studies to define different variations with addition of other subtypes. Accordingly, classical wedgeshaped livers were present in 57.3% specimens. Considering different morphological features, 78 (70.9%) variant livers were noted in terms of shape (as transverse saddle shaped, square shaped, globular, quadrilateral, pyriform or boot-shaped), altered numbers and position of fissures (affecting either one or more lobe in addition to absent fissure for ligamentum teres) or lobes (as aplasia, hypoplasia or hypertrophy) or processes (in addition to abnormalities of processes extending from caudate or quadrate lobe tongue-like process or appendix fibrosa hepatis or mini-accessory lobe) or impressions (as costal or variant visceral impressions affecting inferior surface) or evidence of pons hepatis(35.5%) orin combinations of all above.

Awareness of hepatic surface variation is worth knowing in successful planning of hepatobilliary surgeries with least complications.