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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_770_Библиотеки_им_академика_М_И_Перельмана
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11 Anatomy oftheColon: Rectum toIleocaecal Valve
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(i) (ii)
Fig. 11.8 Ascending colon (i) 3D view of a triangular fold in ascending colon (arrows); (ii) 2D coronal view showing
ascending colon (AC). Green arrow=appendix
11.3.8 Ileocaecal Valve (ICV)
It is easy to identify the ICV valve because its
position is constant relative to the terminal ileum
and caecum. It demarcates the caecum from the
ascending colon. The appearance of an ICV varies from a labial type with a slit-like elongated
appearance to a more bulbous polypoidal or papillary type (Fig.11.9a (i) and (ii)). A bulbous or
papillary ICV causes a prominent polypoidal
appearance with a central depression. A specic
feature of the ICV is a depression or ‘pit’ orice
[3] where the terminal ileum empties into the
right colon. This orice may be visualised on
both 2D and 3D views as shown in Fig.11.9a
(iii). An ICV on a CTC study may be open (patent) or closed. Figure 11.9b demonstrates a
closed IVC. If it is open, then reux of carbon
dioxide may occur (Fig.11.9c (i)–(iv)). The ICV
is located postero-medially where the terminal
ileum enters the caecum. An ICV may be completely replaced with fat (Fig.11.9d (i) and (ii)).
It may have a high intensity (red) on translucent
display (TD) as shown in Fig.11.9 (iii). Polyps or
adenocarcinoma may occur on the surface of the
ICV because it is covered by mucosa.
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a(i) a(ii)
a(iii) b(i)
J. H. Bortz
b(ii)
Fig. 11.9 Ileocaecal valve. (a) (i) 3D view shows labial
ICV (open black arrow); (ii) 3D view of a bulbous ileocaecal valve (black arrow). Appendiceal orice (circle);
(iii) 3D view of ICV showing depression or ‘pit’ orice
(open black arrow) where the terminal ileum empties into
right colon. Closed arrow= triangular folds. (b) (i) 2D
c(i)
coronal view of a closed ICV.Terminal ileum (TI); caecum (C); ascending colon (AC); descending colon (DC);
(ii) 2D axial view of a closed ICV (red circle). (c) (i) 3D
view showing patent ICV (closed black arrow) and triangular folds (open black arrows);
11 Anatomy oftheColon: Rectum toIleocaecal Valve
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c(ii) c(iii)
c(iv) c(v)
137
Fig. 11.9
arrow) with air in the terminal ileum (TI). Caecum (C);
descending colon (DC); (iii) 2D axial supine view showing patent ICV (green circle); (iv) Colon- map showing
(ii) 2D coronal view of a patent ICV (white
reux of gas into small bowel (SB grey) due to patent ICV
(blue arrow); (v) 2D coronal view showing small bowel
valvulae conniventes (open white arrows) and gas in
stomach (S).
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d(i) d(ii)
d(iii)
J. H. Bortz
Fig. 11.9
nantly fatty ICV (green, open black arrow); (iii) TD shows high intensity ICV (red, open white arrow)
(d) (i) 2D soft tissue axial view of a fatty ICV (white arrows); (ii) TD (translucent display) shows predomi-
11.3.9 Caecum
This colon segment is proximal to the ICV; its
conguration and position may change as shown
in Fig.11.10(i) and (ii). This occurs because 10%
of people have no peritoneal xation of the
ascending colon thereby allowing for caecal
mobility (Fig.11.10 (iii) and (iv)). The caecum is
more capacious than the ascending colon.
11 Anatomy oftheColon: Rectum toIleocaecal Valve
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(i) (ii)
(iii) (iv)
139
Fig. 11.10 Caecum (i) 3D view of ICV (closed black
arrow), caecum, proximal ascending colon (AC), and
appendiceal orice (open black arrow); (ii) 2D coronal
view: ascending colon (AC); ileocaecal valve (ICV); caecum (C); descending colon (DC); (iii) Supine colon-map
11.3.10 Appendix
The vermiform appendix is part of the caecum.
Its length varies from 2.5 to 33cm [11]. Its average length is between 5 and 10 cm: its base is
usually situated 2 cm below the ICV. Its intraabdominal position may vary widely depending
on the peritoneal fold which represents the mesentery of the appendix [11, 12]. The convergence
of the three taeniae coli in the caecum form two
showing abnormal position of caecum (C) below the
TC. Rectum (R); sigmoid colon (S); descending colon
(DC); transverse colon (TC); ascending colon (AC); (iv)
Prone colon-map shows normal position of caecum (C)
indicating mobility with postural change. Rectum (R)
prominent folds called the crow’s feet that ank
the appendiceal orice and is shown on the 3D
endoluminal view (Fig. 11.11a (i)) [3].
Figure11.11a (ii) and (iii) demonstrate the orice of the appendix and appendiceal lumen.
Figure11.11b (i)–d (iv) are a range of 2D and 3D
images of the appendix in various locations in the
abdomen. Figure 11.11e (i) and (ii) show the
appendix in the inguinal canal.
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a(i) a(ii)
a(iii) b(i)
J. H. Bortz
Fig. 11.11 Appendix. (a) (i) 3D view of appendiceal ori-
ce (open black arrow) and crow’s feet (closed black
arrows); (ii) 3D view of orice of appendix (open black
arrow); (iii) 3D view of appendiceal lumen (open black
arrows). (b) (i) Air in appendix (open white arrow) on 2D
coronal view;
11 Anatomy oftheColon: Rectum toIleocaecal Valve
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b(ii) c(i)
c(ii) d(i)
141
Fig. 11.11
dix (open white arrow). (c) (i) 2D coronal view showing
malrotated caecum (C), air-lled appendix (open white
arrow), and ileocaecal valve (ICV); (ii) 2D coronal view
(ii) 2D sagittal view showing air in the appen-
showing air in terminal ileum (open red arrow) and air in
appendix (closed white arrow). (d) (i) 2D axial showing
barium lled appendix (open red arrow);
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J. H. Bortz
d(ii)
d(iv) e(i)
d(iii)
Fig. 11.11
lled with air (open white arrow); (iii) 2D sagittal view
showing appendix (open red arrow) adjacent to spine; (iv)
(ii) 2D axial showing retrocaecal appendix
2D coronal view showing sub-hepatic appendix (yellow
arrow). (e) (i) 2D coronal view showing appendix (closed
red arrow) in inguinal canal;
11 Anatomy oftheColon: Rectum toIleocaecal Valve
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143
e(ii)
Fig. 11.11
(closed red arrow) in inguinal canal
(e) (ii) 2D sagittal view showing appendix
11.4 Malrotation oftheBowel
Malrotation is a failure during the development
of normal rotation of any part of the intestinal
tract. Congenital malrotation of the midgut often
presents clinically in the rst month of life; more
commonly in the rst post-natal week where the
newborn presents with bilious vomiting [13].
This would be a medical emergency as the cause
may be due to malrotation of the midgut with volvulus. If an early diagnosis is not made, this
could result in complications, such as ischaemia
of the small bowel loops, and subsequent death.
Most patients born with malrotation will be
asymptomatic with a normal clinical history [14].
Malrotation in such patients is an incidental nding when they undergo a screening CTC exami-
nation after the age of 50years. Malrotation does
not occur in isolation in this abnormality. With it
comes malxation of the mesentery, which
results in abnormal mobility of portions of the
bowel [15]. Figure11.12a (i)–b are examples of
such a pathology.
At CTC when patients with bowel malrotation
are shown the images, they are often very surprised as they were unaware and asymptomatic
with a normal clinical history. They usually do
not entertain the possible need for surgical intervention . Some authorities advocate surgical correction (Ladd’s procedure) for all patients with
malrotation, regardless of age [16]. Failure to
correct the abnormality may result in an intussusception or volvulus, in the future. This would
then become a surgical emergency to correct the
underlying abnormality.
11.4.1 Mobility ofColon Segments
The sigmoid colon and transverse colon are intraperitoneal structures and may be mobile depending on how loosely the mesentery is attached to
them [3]. In view of such mobility, it often
appears as if polyps move with postural change
(supine to prone) during a CTC study. A mobile
lesion on CTC should not be assumed to be stool.
The ascending colon, descending colon, and rectum are retroperitoneal in position and do not
usually change position. As shown in Fig. 11.1
above, the caecum usually lies in the right iliac
fossa. However, in approximately 10% of the
population the caecum and ascending colon are
incompletely xed which allows for a wide range
of mobility. Although displacement of the caecum and ascending colon does not cause
symptoms, the onset of appendicitis may be difcult to diagnose clinically, especially if the displaced colon lies in the left upper quadrant of the
abdomen or is sub-hepatic in position.
Figure11.13 (i) and (ii) demonstrate mobility of
the caecum.
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J. H. Bortz
a(i)
b
a(ii)
Fig. 11.12 Malrotation of the bowel. (a) (i) Supine
colon-map of a malrotated caecum.(C). Rectum (R);
descending colon (DC); transverse colon (TC). Note the
gap in the ascending colon (technical); (ii) 2D coronal
view of a malrotated cecum (C). (b) Supine colon-map
showing sub-hepatic caecum (C). Rectum (R)
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