J Anat. Soc. India 49(2) 123-126 (2000)
Gross Anatomy of the Caudate Lobe of the Liver
Sahni, D., Jit, I., Sodhi L. Department of Anatomy, Postgraduate Institute of Medical Education and Research, Chandigarh, India
Abstract : Gross anatomy of the caudate lobe of the liver was studied in specimens obtained from 200 adults, 25 fetuses, 10 neonates and 10 children. The superficial surface of the caudate lobe was seen to have two parts: a posterior and an inferior. This was well marked in all the fetal livers where a convex ridge separated them. The anterior border of the caudate lobe was deeply concave in the livers of all fetuses, neonates and children. The upper part of the posterior surface was found to be included in the bare area of the liver even in adults. A well marked groove extended on the inferior surface in 92% fetuses. However, in adult livers only a faint groove could be identified in 9% instances. The papillary process which was present in 100% fetal livers was seen only in 33.5% adult livers.
Surface areas and transverse diameters of the caudate lobe and right lobe were also measured and ratio thereof was determined in 100 normal livers.
Keywords : Spigelian lobe, Caudate process, Papillary process, Liver.
The caudate (Spigelian) lobe (CL) of the liver is described to be located on its posterior surface between the inferior vena cava on the right, fissure for the ligamentum venosum on the left and porta hepatis anteriorly, above it is said to be continuous with �e�esuperior�f�f surface (Williams et al 1995). Its right anterior part is connected to the right lobe (RL) of the liver by the caudate process (CP). Opposite the tuber omentale of the left lobe but separated by the lesser omentum, the inferior surface of the CL may present a small rounded projection called the papillary process (PP). During recent times the CL has acquired considerable importance. It has been shown by Mullane and Gliedman (1966) that in cases of cirrhosis of the liver the CL enlarges while the RL shrinks. To distinguish between normal and cirrhotic livers some workers measured under ultrasonography, one or more diameters of CL and RL (Harbin et al, 1980; Giorgio et al, 1986, Hess et al. 1989). However, none of them measured the surface areas of the two lobes. Further, the number of normal subjects examined by them was rather small and sexual dimorphism in the diameters or surface areas of the two lobes was not elucidated.
As the gross anatomy of the CL including its shape, size and peritoneal relations seems to have not been described in detail in the past it is proposed to study the same in the extensive material collected in the department. The present paper also gives the ratio between the transverse diameters of CL and RL and between the surface areas of the two lobes in normal liver autopsy specimens.
Material and Methods :
Material for the present study consisted of apparently healthy livers of 200 adults (138 males, 62 females) aged between 18 and 80 years belonging to Chandigarh zone of northwest India on which medicolegal postmortems had been conducted by the second author. At autopsy the liver was taken out as usual. It was washed and put in 10% formalin for a short period and anatomy of CL studied. In 100 (50 male, 50 female) normal livers, the surface areas of CL and RL were measured as described by Sahni et al. (1997); with the help of a Vernier caliper, the transverse diameters of CL and RL were measured at the level of the right lateral border of the portal vein (Harbin et al, 1980). The ratios of the surface areas and that of transverse diameters of the two lobes were calculated. In addition, gross anatomy of CL was studied in 25 fetuses (12 males; 13 females), 10 neonates (5 males, 5 females) and 10 children (5 males, 5 females).
Caudate lobe in adults
The superficial surface of the CL was found to have two parts, the posterior and inferior. The former which came in contact with diaphragm looked backwards and when traced below it sloped into the inferior surface which faced downwards and projected as the roof of the superior recess of the omental bursa. The rounded, convex ridge between the two surfaces was seen only in 5% instances (Fig. 1). The length (from above downwards) of the diaphragmatic surface could be greater than the anteroposterior diameter of the inferior surface or vice versa. A part of the right side of the CL extended to the right covering the IVC partially in 44 (22%) instances or completely in 10 (5%) specimens. However, unlike the CP, it did not merge with the right lobe but showed a distinct right margin. A shallow fetal type of groove on the surface of CL was seen in 18 (9%) adult specimens (Fig. 2).
From the right triangular ligament the peritoneum continued downwards, forwards and to the left as the inferior layer of the coronary ligament; crossing the posterior surface of the right suprarenal gland (sometimes the upper pole of the right kidney). It extended to the left behind the inferior vena cava along the posterior margin of the CP from where it got reflected upwards along the left margin of the groove for the inferior vena cava to reach the upper part of the CL; crossing the latter, it extended to the left and joined the posterior layer of the left triangular ligament to form the lesser omentum. The upper border of the CL was delineated by the left hepatic vein opening into the inferior vena cava in the bare area of the liver. A small uppermost part of the CL was seen to be included in the bare area of the liver (Fig. 3).
In 189 (94.5%) instances, the shape of the CL was more or less rectangular with rounded corners and its long axis directed anteroposteriorly. In 9 (4.5%) specimens the appearance was somewhat piriform (Fig. 4). In the remaining 2 (1%) specimens the shape was irregular. The anterior and posterior margins were usually convex. However, in all instances the length between the upper and anterior borders was greater than the maximum transverse diameter of the CL.
Out of 200 adult livers the CP was found to be present in 119 (59.5%) specimens (76 males, 43 females). From the right anterior angle of the CL the CP extended anteriorly and to the right to merge into the RL in 109 (54.5%) specimens. Depending upon the position of fissure on its left at its commencement, its base could be broad or narrow. It was present between the porta hepatis anteriorly and the fossa for the inferior vena cava posteriorly. Its length varied from 14 to 24 mm (average 19 mm) and breadth from 3 to 5 mm (average 4 mm). In 10 (5%) livers, the CP emerged from the right margin of the CL somewhat posterior to its normal position; it was directed anteriorly and to the right in 9 (4.5%) specimens while it extended transversely to the right in one (0.5%) instance (Fig. 5) CP was however absent in 81 (40.5%) specimens.
Fissures of variable length and position were present on various borders of the CL in 137 (68.5%) specimens (92 males, 45 females). In 104 (52%) instances the fissure was located at the junction of the CP and the CL at its anterior border; It was oblique in 98 (49%) specimens (Text-Fig. 1a) and anteroposterior in 6 (3%) instances (Text-Fig. 1b). In one instance (0.5%) an additional fissure was present on the anterior border along with a fissure at the junction of CL and CP (Text Fig. 1c). In 8 (4%) specimens there was no fissure between the CP and CL, but a fissure was present on the anterior border at variable distance left of CP (Text Fig. 1d). The left border showed a fissure in 13 (6.5%) instances in addition to a fissure present at the junction of CL and CP (Text Fig. 1e). In 9 (4.5%) specimens a fissure was seen on the right border in addition to a fissure between CL and CP (Text Fig. 1f). The
Text Fig. 1. A diagramatic representation of various shapes of the CL, CP and fissures.
The diagrams show :
(a) an oblique fissure separating the CP from the CL.
(b) an anteroposterior fissure between the CP and CL. A fetal type of groove is indicated by a dotted line.
(c) Shows an additional fissure on the anterior border.
(d) Shows absence of a fissure at the junction of CP and CL but a fissure is present on the anterior border of the CL.
(e) Shows an additional fissure on left border.
(f) indicates an additional fissure on right border.
(g) an additional fissure on superior border.
(h) a fissure is seen on each of three border.
(i) absence of a fissure, a fetal type of anterior border.
Fig. 1. Shows a convex border between the upper and lower parts of CL (arrow). X 1.
Fig. 2. Shows a fetal type of groove (arrow) on the inferior surface of the CL. There is no CP. X1
Fig. 3. Caudate lobe of an adult liver showing bare area (arrow). The caudate process is located on the right of a small fissure. X1
Fig. 4. Shows a piriform CL in an adult liver. No fissures are present on the borders. X1.
Fig. 5. Shows the CP arising from about the middle of the right border of the CL. No fissure is seen on any border. X1.
Fig. 6. CL of the liver of 176 mm female fetus showing a concave anterior margin, and an oblique groove on the superficial surface and a well marked PP. X. 1.
posterior border had a fissure only in one instance (0.5%) in addition to a fissure between CL and CP (Text Fig. 1g). One specimen (0.5%) showed three fissures at various borders of the CL (Text Fig. 1h). The fissure was absent in 63 (31.5%) specimens (Text Fig. 1i). The length of these fissures varied from 2 mm to 24 mm.
In 67 (33.5%) instances a PP could be identified on inferior surface near the left anterior angle; it was appreciable in 41 (20.5%, slightly prominent in 23 (11.5%) and fairly prominent only in 3 (1.5%) specimens and was absent in 133 (66.5%) cases.
The maximum anteroposterior diameter of the CL was 58.0 �} 4.67 mm (range 40-72 mm) in males and 45.2 �} 4.6 mm (range 36-57 mm) in females (p < 0.001); the maximum transverse diameter measured 30.2 �} 4.5 mm (range 18-41 mm) in males and 25.0 �} 3.1 mm (range 22-29 mm) in females (p > .001).
Using the method given by Harbin et al. (1980) the average transverse diameter of the CL was found to be 32.7 �} 7.6 mm (range 19-43 mm) in males and 26.8 �} 5.5 mm (range 15-32 mm) in females (p < .001) and that of the RL was 88.3 �} 13.2 mm (range 70-119 mm) and 81.8 �} 12.3 mm (range 69-98 mm) respectively (0 < .05). The surface area of the CL was 23.4 �} 6.5 cm2 (range 15-43 cm2) in males and 20.9 �} 3.9 cm2 in females (range 13-28 cm2) (p < .05) and that of RL was 86.4 �} 18.8 cm2 (range 54-123 cm2) in males and 80.3 �} 17.3 cm2 (range 54-112 cm2) in females (p > .05).
The average ratio of the transverse diameter of CL to that of RL (CL/RL) was found to be .31 �} .06 (range .23 ? .40) in males and .21 �} .07 (range .14 ? .29) in females) (p < .001); CL/RL ratio of surface area was .19 �} .05 (range .10?.29) in males and .18 �} .04 (range .12?.28) in females (p > .05).
Caudate lobe in fetuses, neonates and children
The shape of the CL in the fetuses, neonates and children was mostly irregularly quadrilateral. The larger posterior surface was separated from the smaller inferior surface by a convex border in all specimens of fetuses and neonates. However, in children the convex ridge could be identified only in 3 (30%) caudate lobes. The anterior border was markedly concave and the posterior border was convex in all specimens. From the maximum concavity of the anterior margin a shallow groove extended backward on the inferior surface (Fig. 6). The groove which was prominent in 92% younger fetuses, became less distinct in older fetuses and could not be observed in 2 out of 4 fetuses of more than 200 mm CR length. This groove was present in 9 (90%) neonates; in children it could be identified clearly only in 50% instances. The CP was found to be present in 100% fetuses, neonates and children and emerged from the CL from its right anterior border. In fetuses and neonates, a PP was present in 100% specimens but in children its incidence decreased to 7(70%) instances.
A small fissure was present at the junction of CP and CL only in 9 (36%) fetuses, in one instance another small fissure was present on the left border. In the neonates, a fissure was seen in 5 (50%) instances at the junction of CP with CL. In one instance an additional fissure was present on the left border. However, in children the fissure at the junction of the CL and CP was identified in 6 (60%) specimens.
Textbooks of anatomy described the presence of the CL on the posterior surface of the liver (Blount and Lachman, 1966; Williams et al. 1995). According to Heloury et al. (1988), it is a `projection' from the posterior aspect of the diaphragmatic surface of the liver and lies between the hilum of the liver and inferior vena cava. Auh et al. (1984) described its location on the posterosuperior surface of the liver.
In the present material the superficial surface of the CL presented two parts a posterior and an inferior. The former faced backward and downward and was in contact with the diaphragm while the latter looked downward and formed the roof of the superior recess of the omental bursa. The two surfaces were well marked and were delineated by a convex ridge in fetuses and neonates and some children. The ridge could be recognized only in 5% adult livers. The upper part of the posterior surface was found to be devoid of peritoneum and formed a part of the bare area of the liver. This fact seems to have not been recorded in books and papers on the subject.
Nawar et al. (1980) examined 20 fetal livers between the age of 6 and 8 months and described the presence of a �edeep furrow�f on the surface of the CL dividing it into a right and a left �eterritory�f the former continued into the caudate process. The present workers also noted the presence of a groove extending from the anterior concave margin of the fetal CL backwards and to the left. This groove was present in the caudate lobes of 92% younger fetuses but could not be observed in 2 out of 4 fetuses of more than 200 mm CR length. Further this groove could be seen in 90% neonates and 50% children, but could not be identified in 91% adult livers, showing thereby that the groove tends to become inconspicous and even disappears with advancing age. The anterior border of the CL is distinctly concave in fetuses and neonates. With advancing age, the concavity of the anterior border becomes less marked and ultimately becomes convex in adults. This change in the shape of the anterior border took place pari passu with the disappearance of the fetal groove. A PP is described to be located on CL opposite the tuber omentale of the left lobe of liver (Blount and Lachman, 1966). Our results reveal that although PP is always present in the livers of fetuses and neonates it tends to become less prominent in children in whom its incidence was 70% and in adults the incidence decreased to 33.5%. Auh et al. (1984) observed that in fetuses CP and PP may be separated by a groove of variable depth which is usually oriented in a sagittal or parasagittal plane, but sometimes along a semi-coronal plane. Contrary to the observations of Heloury et al. (1988) who found the PP to be bulky in 8 out of 30 specimens with no pathological involvement, we noticed a fairly prominent PP only in 3 (1.5%) adult specimens; an extremely prominent PP was not observed in any specimen.
1. Auh, YH, Rosen, A, Rubenstein, W.A, Engel, IA, Whalen, JP, Kazam, E. (1984): CT of the papillary process of the caudate lobe of the liver. American Journal of Roentgenology 142: 535-8.
2. Blount, RF, Lachman, E: In Morris�f Human Anatomy. Anson BJ (editor) 12th ed. McGraw-Hill, New York, : p-1353 (1966)
3. Giorgio, A; Amoroso, P, Littieri, G, Fico P, Stefano, G, Finelli, L (1986): Cirrhosis: Value of caudate to right lobe ratio in diagnosis wth US. Radiology 161: 443-5.
4. Harbin, W.P. Robert N.J: Ferrucci, J.T. (1980): Diagnosis of cirrhosis based on regional changes in hepatic morphology. Radiology 135 : 273-83.
5. Heloury, Y; Leborgne, J; Rogez, JM; Robert, R; Barbin, J.Y; Hureau, J. (1988): The caudate lobe of the liver. Surgical Radiological Anatomy 10: 83-91.
6. Hess, C.F, Schmiedl, U, Koelbel, G, Knecht, R, Kurtz, B, (1989): Diagnosis of liver cirrhosis with US: Receiver ? operating characteristic analysis of multidimensional caudate lobe indexes. Radiology 171: 349-51.
7. Mullane, JF, Gliedman M.L. (1966): Elevation of the pressure in the abdominal inferior vena cava as a cause of hepatorenal syndrome in cirrhosis. Surgery 59: 1135-46.
8. Nawar, N.N.Y; Mikhail, Y; Bahi, el Din, I.A. (1980): Fetal hepatic vessels and subsegmentation with evidence of further subdivision. Acta Anatomica 108: 309-93.
9. Sahni, D, Jit, I, Sodhi, L, Harjeet (1997): Weight and surface area of the liver in northwest Indian adults. Journal of Anatomical Society of India 46: 67-6.
10. Williams, P.L, Bannister, L.H, Berry, M.M, Collins, P, Dyson, M, Dussek, JE. In: Gray�fs Anatomy. The anatomical basis of medicine, and surgery 38th ed. Churchill Livingstone, London, p. 1797 (1995).