Morphological variations of liver in humans and its surgical relevance.

Abstract

Background: The knowledge of normal and variant anatomy of the liver is important during radiological investigation and surgery. Variations in the liver morphology can be either congenital or acquired. The common congenital anomalies in liver are agenesis of the lobes, absence of segments, deformed lobes, smaller lobes, atrophy of the lobes and hypoplastic lobes. It is mainly due to defective development or excessive development and sometimes these deformities are present with abnormality of diaphragm and suspensory apparatus of the liver. Though variation in the branching pattern of the hepatobiliary system has been extensively studied, the morphological variations of the liver have not been studied at length. Methods: The study was conducted in the Department of Anatomy of our institution after obtaining the ethical clearance.100 liver specimens in the Department were used for the study. The morphological variations of the liver such as changes in size and shape, presence of pons hepatis, accessory lobes and fissures were noted. Photographs were taken to document the variations. The results obtained were then tabulated. Results: The fissures in right lobe was 38 % and left lobe 13%, caudate lobe fissures were 6 % and quadrate lobe was 21%, pons hepatis was 10%. Grooves in the anterior surface was 9%. Conical shaped right lobes were 28% and notched border was 10%. Elongated left lobe was 17% and quadrate lobe with tongue projection was 17%, bilobed quadrate lobe was 5% and accessory lobe was 9 %.The commonest mean weight of liver ranged between 1400- 1700 gms irrespective of sex. According to Netter’s classification, type 1 livers were 50% , type 2was 20%, type 3 was nil, type 4 was 5%, type 5 was 3 %, type 6 was 12% and type 7 was 10%. Conclusions: Knowledge of such variations is also important as these do not always remain clinically latent though most often it may be clinically asymptomatic. Awareness of these variations would help both the surgeons and radiologists to avoid misdiagnosis of cases and unnecessary surgical complications.