The Inferior Accessory Hepatic Fissure: An Anatomic Study
6
24 1 pp. 98 - 103, 1988 Journal of Korean Radiologic al Society , 24 ( 1) 98-103, 1988 The Inferior Accessory Hepatic Fissure: An Anatomic Study U sing Cadaver and CT Jae Hoon Li m, M.D., Young Tae Ko , M.D. and Kyung Nam Ryu . M.D. Department of Radiology , Kyung Hee University Hospital 14 100 f7lJ.91 CT 11 2cm 46 To assess th e sh ape and frequency of th e inferior accessory he pati c fis sur e, authors observed 14 cada ve ric li ve rs and 100 abdominal ( T sca ns. Th e in fe ri or accessory hepati c fi ss ure was pr esent in eight of 14 ca dave ri c li ve rs and eleve n of 100 abdom i na l (T scans. A sh a ll ow notch was present in 46 of 100 (T scans and many these notches ma y represent e it her shall ow or dee p fi ss ures . Th e in f eri or accessory hepatic fis sur e is not a ra re anato mi c va ri ation as th e fi ssure was enco untered in 11l 0 re th an h alf of the ca davers and ( T scans I. Introduction The inferior accessory hepatic fissure is a fissure through the pare nchyma of the posterior segment of the right he patic lobe in a coronal Received December 30, 1987, acc epted January 22, 1988 or sagittal , or between the corona l and sagittal planes. It is a peritone al invaginat ion into the liver parenchyma directed la ter ally and poster- iorly from the medial inferior surface of the right hepatic lob e. Its sectional anatomic and so nographic ap pe a rances were d escribed 1) • Herein , we describe the shape and frequency of the fissure , b ased on a st ud y of anatomic cadaver dissections and a bd ominal CT scans . - 98-
The Inferior Accessory Hepatic Fissure: An Anatomic Study
!íH‘H~ t tr 24 1 pp. 98 - 103, 1988 Journal of Korean Radiological
Society, 24(1) 98-103, 1988
The Inferior Accessory Hepatic Fissure:
‘
An Anatomic Study U sing Cadaver and CT
Jae Hoon Lim, M.D., Young Tae Ko , M.D. and Kyung Nam Ryu .
M.D.
Department of Radiology, Kyung Hee University Hospital
IJJJf j
B 9
. 14 100 f7lJ.91 CT .
14 8 2~3cm 3~4cm . CT 100
11 f7l. 2cm 46 í9l CT ßß tE
f7! .
.
To assess th e shape and frequency of the inferior accessory
hepatic fissure, authors observed 14 cadaveric
live rs and 100 abdominal ( T scans. The inferior accessory hepatic
fi ssure was present in eight of 14 cadave ri c
live rs and eleven of 100 abdominal (T scans. A shall ow notch was
present in 46 of 100 (T scans and many
f these notches may represent either shallow or deep fissures . The
inferior accessory hepatic fissure is not
a ra re anatomic va riation as the fissure was encountered in
11l0re than half of the cadavers and ( T scans
I. Introduction
The inferior accessory hepatic fissure is a
fissure through the parenchyma of the posterior
segment of the right h e patic lobe in a coronal
1 987 12 30 1988 l
22 .
planes. It is a peritone a l invagination into the
liver parenchyma directed la terally and poster
iorly from the medial inferior surface of the
right hepatic lobe . Its sectional anatomic and
sonographic appearances were described 1) •
Herein, we describe the shape and frequency
of the fissure , based on a study of anatomic
cadaver dissections and a bdominal CT scans.
- 98-
- Jae Hoon Lim. et al: The Inferior Accessory Hepatic F issure: An
Anatomic Study Usi ng Cadaver and CT-
11. Materials and Methods
The inferior and medial surfaces of the livers of 14 cadavers were
reviewed concentrating particu1ar importance on the shape and depth
of the inferior accessory hepatic fissure. Ab domina1 CT scans in
100 consecutive patients without 1iver masses were reviewed
retrospec tively. CT examinations were performed with a Toshiba
TCT-80A scanner using 10mm co1- 1imation and 9 sec scan times.
Consecutive CT scans through the upper abdomen were done during
deep inspiration, with the patient supine, at interva1s of 10-15mm.
Ora1 and intravenous contrast media were administered in majority
of cases . Antispasmodics (Buscopan@, Scopo1- amine buty1bromide ,
Boehringer 1nge1heim, Korea Limited , Seou1) was administered in
travenous1y to inhibit bowe1 perista1sis.
111. Results
Among the 14 cadaveric 1ivers, the inferior accessory hepatic
fissure was persent in eight livers (Tab1e 1). The fissures were
deep in three cases, the depth being some 2.5cm and 1ength being
some 4cm (Fig. 1-a). Five 1ivers showed shallow fissures , the
depth being 1ess than 1.5cm and the 1ength being 1ess than 2cm
(Fig. 1-b). The fissure started from the right side of the porta
hepatis just latera1 to the gallb1adder neck. 1n or between the
corona1 and parasagit ta1 p1anes, the fissure is a true
invagination of the viscera1 peritoneum running downwards to
Table 1. Frequency of IAHF in 14 Cadavers.
Fissure Number
Fig. 1 Anteroinferior surface of cadaveric livers
a. A cleepfissure (open arrow) separates the “ m ferior accessory
hepatic lobe (IAHL)" from the rest of the liver. The fissure
extencls downwarcls and comes in direct contact with the anterior
surface of the right kidney (retracted downwards). Note the
relation between the fissure and the gallbladder (GB). C= caudate
process (partly broken) of the caudate lobe b. A shallow fissure
(arrow). GB = Gallbladder c. A notch (arrow) at the site of the
inferior ac cessory hepatic fissure ‘ GB = Gallbladder
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- 24 1 1988-
the inferior surface of the liver. The fissure divided the inferior
part of the posterior seg ment into the anterolateral and
posteromedial parts. Among the six livers without fissure ,
four
livers showed a notch at the medial surface of the liver just
lateral to the gallbladder neck, ex actly the same site at the
fissure (Fig. 1-c). The
a
c
remaining two livers have no trace of the fissure or notch at
all.
In the series of 100 CT scan , accessory
fissures were observed in eleven cases (Table 2). Thefissure
measured some 2cm (Fig. 2-a). The fissure directed posterolaterally
from the gallbladder neck. Shallow notches were observ-
Fig. 2 CT scans through the lower part of the liver in three c1
ifferent patients. a. A fissure is clearly c1 emonstratecl by fat
within
’ the fissure (arrow) b. A notch at the site of the inferior
accessory hepatic fissure (arrow). c. CT scan showing no eviclence
of the fissure
-100 -
Table 2. Frequency of IAHF in 100 CT’s
Jae Hoon Lim. et al: The Inferi or Accessory Hepatic Fissure: An
Anatomic Study Using Cadaver and CT-
Fissure Number
ed in 46 cases (Fig. 2-b). The site of the not ches was exactly
the same area as the well developed fissure. 1n the remaining 43
cases, there was no trace of a fissure or notch (Fig. 2-c).
1V. Discussion
Topographically there are three major fissures in the liver 2-4).
The interlobar fissure , or fissure for the gallbladder, lies along
the Cantlie line, an imaginary line connecting the inferior vena
cava and the gallbladder. It divides the liver into the right and
the left lobes. The fissure for the ligamentum teres divides the
left lobe into the lateral and medial segments. The fissure for the
ligamentum venosum separates the caudate lobe posteriorly from the
left lobe anteriorly. 1n addition to these three fissures , there
is a shallow fissure in the inferior part of the right hepatic
lobe. This fissure has not been discussed until recently. Lim et
al') described the fissure in detail using transverse cadaveric
sections and ultrasonic appearances and named the inferior
accessory hepatic fissure.
On cadaveric livers, the depth of the fissure varied from a notch
to a fissure some 3cm deep (Fig. l-a, b, c). Two of eight fissures
were pret ty deep and the liver parenchyma posteromedial to the
fissure is clearly separated from the rest of the right hepatic
lobe by the deep fissure (Fig. l-a). The separated hepatic
parenchyma may be called “ inferior accessory hepatic lobe" since
the accessoη hepatic lobe is defined as the hepatic tissue that was
clearly super numerary and attached to the remaining liver by a
pedicle of liver tissue or mesentery6).
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b
Fig. 3 Inferior accessory hepatic fissure in patients with ascites.
a. A transverse ultrasound scan in a patient with cirrhosis of the
liver. The inferior accessory hepatic fissure is filled by ascitic
fluid (arrow). RK = Right kidney. F = Ascitic fluid. b. A CT scan
in another patient with cirrhosis of the liver. Arrow points in
inferior accessory hepatic fi ssure fi lled by ascitic fluid. N =
Lymphnode in the portocaval space
- , 24 1 1988-
The frequency of the inferior accessory hepatic fissure has not
been known. Lim et al') reported 15 (0.8%) fissures out of 2000 ab
dominal sonogram. However, this rate is not a true incidence as the
fissure is too thin and meager to be seen on ultrasonogram,
especial ly if a sonographer is not interested in the
a
b
fissure. The fissure was observed in eight (57%) of 14 cadavers
(Fig. 1-a, b). Three livers have a deep fissure and five have a
shallow fissure. On CT scans, however, the fissure was present in
only eleven (11%) of 100 scans. This discrepancy between cadaveric
and CT obser vations is not surprising. The peritoneal in-
c
d
Fig. 4 Hypertrophy of the “ inferior accessory hepatic lobe" a,b,c.
A hepatic parenchyma bulges downwards and contacts the anteríor
surface of the ríght kídney (RK). This “ mass" simulates a
pedunculated hepatoma. PP = Papillary process of the caudate lobe.
CP = Caudate process of the caudate lobe. V=Inferior vena cava.
GB=Gallbladder d. A parasagittal sonogram confirms the continua
tion of the liver parenchyma extending downwards. An echogenic line
(arrows) represents the inferior accessory hepatic fissure
- 102-
- Jae Hoon L im. et al: The Inferior Accessory Hepatic Fissure: An
Anatomic Study Us ing Cadaver and CT-
vagination contains various amount of fat. The less is the amount
of fat in or between the fissure , the less is the chance of
visualization on CT. This also explains such a low rate of
visualization of the fissure on ultrasound 1 . 5).
Mesenteric fat or ascites may fill the gap of the fissure and
facilitate visualization on ultrasonogram and CT (fig. 3-a, b). A
large number of livers in which a notch was visualiz ed on CT
scans (Fig. 2-b) probably have the in ferior accessory hepatìc
fissure. If many of these notches are considered to represent deep
or shallow inferior accessory hepatic fissure , the overall
frequency of the fissure is roundabout 60%. This rate is consistent
with the frequen cy observed in cadavers.
The relationship between the presence of the inferior accessory
hepatic fissure and the overall anatomy of the liver is not
certain. Lim te al described the close relationship between the
fissure and the posterior branch of the right portal vein l). This
suggests some possible rela tionship between embryologïcal
development of the liver and the fissure.
The significance of the fissure is uncertain. Sonographic or CT
visualization of the fissure is important for localization of a
tumor before surgeryl). Sometimes a pathologic process arises
within the accessory lobe. We observed a case of hypertrophy of the
“ inferior accessory hepatic lobe" mimicking a pedunculated
hepatoma (Fig. 4-a, b, c , d). A Surgeon may make use the fissure
as a landmark in surgery. Furthermore, if the fissure is deep, it
could be used as a guide for hepatic subsegmentectomy in patients
with hepatic dysfunction.
In summaη our cadaveric and CT study established relatively high
frequency of the in ferior accessory hepatic fissure. The fissure
, if visualized on ultrasound or CT, may be useful in surgery in
patient with diminished hepatic reservoir function.
REFERENCES
1. Lim JH, Ko YT, Han MC, et a/: The inferior accessory
hepatic
fissure: Sonographic appearance. AjR 149: 495-497; 1987
2. Auh YH, Rubenstein WA, Zirinsky K, et a/’ Accessory
fissures of the /iver: CT and sonographic appearance. AjR
143: 565-572; 1984.
AjR 141: 711-718; 1983
4. Kane RA: Sonographic anatomy of the /iver. Seminar U/tar
sound. 2: 190-19 1981.
5. Fried AM, Kreel L, Cosgrove DO: The hepatic interlobar
fissure: Combined in vitro and in vivo study. AjR 143:
561-564; 1984.
6. Cullen TS: Accessory /obes of the /iver.‘ Arch Surg 11
718-764; 1925