Guidance information on bowel and kidney sizes: Figure 746
Figure 746 Left lateral recumbent projection of abdomen.
1 Diaphragmatic shadow
1(a) Left ‘crus’
1(b) Right ‘crus’
1(c) Cupola
2 12th thoracic vertebra
3 13th rib
4 Skin margin
4(a) Soft tissue shadows of nipples (only just visible)
5 Subcutaneous fat
6 M. rectus abdominis
7 Intraperitoneal fat
7(a) Falciform ligament of liver, mainly fat
8 Mineralised costal cartilages
9 Soft tissue shadow of liver. Caudally this shadow creates border effacement (previously known as a positive silhouette sign) with the soft tissue shadow of the pyloric part of the gastric shadow 9(a).
9(b) Caudoventral margin of liver; left lateral lobe
9(c) Caudodorsal margin of liver; caudate process of caudal lobe
10 Gastric fundus
11 Gastric body
12 Pyloric part of gastric shadow
The lack of gastric gas is causing poor definition of the gastric shadow parts numbers 10 to 12. Shadows of cardia and pylorus are not seen.
13 Jejunum and ileum (seen as tubular soft tissue shadows)
Jejunum and ileum can not be differentiated on non-contrast films, or even clearly on contrast studies. Generally the diameter of all small intestinal bowel is equal.
Guidance for normal size of small bowel
Width of bowel loop is less than 12 mm.
14 Ascending colon (caecum cannot be seen as a separate structure on this film).
15 Transverse colon. In the cat it is a very small portion of bowel and is only rarely seen in abdominal projections.
16 Descending colon
17 Rectum
18 Anus
19 Right kidney
20 Left kidney
Cats’ kidneys are more variable in their location than dogs’ kidneys. They tend to be more caudoventral and overlap on the lateral projections. In addition, the most caudally located kidney is not always left, hence requiring aventrodorsal or dorsoventral projection for an accurate kidney analysis. Kidney shape is similar to the dog but they are smaller in size.
Guidance for normal kidney size
Length of kidney is 2 to 2.5 times the length of the 2nd lumbar vertebral body. It has been reported that in entire cats the length may be 3 times the vertebral body. Both kidneys are similar in size. Kidney size best achieved in ventrodorsal projection.
Kidneys and ureters are retroperitoneal. Ureters are not visible on plain radiographs.
21 Urinary bladder
21(a) Bladder neck. The cat bladder has a long narrow neck so that the bladder’s radiographic position is 2–3 cm cranial to the pubis. This is in contrast to the dog where the position is immediately cranial to the pubis in the female and cranial to the prostate in the male.
21(b) Urethra located in the fat caudal to the bladder neck. The urethra in the cat is very narrow and usually requires contrast material to demonstrate its position.
22 Sublumbar muscles.Although the muscles in the cat are similar to those in the dog their volume is greater, so creating a very distinct soft tissue shadow. In non-domestic predatory cats the muscle mass is very large at the 4th lumbar vertebral level.
23 7th lumbar vertebra
24 Sacrum. Only two sacral segments are present in this cat.
25 Body of ilium
26 Pubic tubercle
27 Femoral bodies
28 Skin margin of hind leg
29 Muscles of hind leg
Figure 747 Right lateral recumbent projection of abdomen. British Domestic Short Haired cat 8 years old, neutered female (same cat as left lateral recumbent projection of abdomen, Figure 745). (Approximately 70% of original size.)
Figure 748 Right lateral recumbent projection of abdomen.
For a routine survey radiograph of the abdomen, a right lateral recumbency is often preferred by many radiographers and radiologists. The most important factor is being consistent with one’s radiographic approach and hence radiographic appraisal and interpretation.
1 Diaphragmatic shadow
1(a) Left ‘crus’
1(b) Right ‘crus’
1(c) Cupola
2 12th thoracic vertebra
3 13th rib
4 Skin margin
4(a) Soft tissue shadows of nipples (just visible)
5 Subcutaneous fat
6 M. rectus abdominis
7 Intraperitoneal fat
7(a) Falciform ligament of the liver, mainly fat
8 Mineralised costal cartilages
9 Soft tissue shadow of liver. Caudally creating border effacement (previously known as a positive silhouette sign) with the soft tissue shadow of the pyloric part of gastric shadow 9(a)
9(b) Caudoventral margin of liver; left lateral lobe
9(c) Caudodorsal margin of liver; caudate process of caudal lobe
10 Gastric fundus
11 Gastric body
12 Pyloric part of gastric shadow
Right lateral recumbency has caused gravitational filling of these ventrally positioned gastric areas (11 and 12). Notice the large shadow compared to the left lateral recumbent projection drawing, Figure 746.
13 Jejunum and ileum. (Seen as tubular soft tissue shadows. See text in left lateral recumbent projection, Figure 746.)
14 Ascending colon. (Note the more ‘normal’ ventral position as compared to left lateral recumbent projection drawing Figure 746.)
15 Transverse colon
16 Descending colon
17 Rectum
18 Anus
19 Right kidney. In the right lateral recumbency the right kidney is more caudally positioned than in the left lateral recumbency.
20 Left kidney
21 Urinary bladder
22 Sublumbar muscles
For numbers 19 to 22 please see corresponding numbers in the left lateral recumbent projection of abdomen, Figure 746.
23 7th lumbar vertebra
24 Sacrum. Only two sacral segments are present in this cat.
25 Body of ilium
26 Pubic tubercle
27 Femoral bodies
28 Skin margin of hind leg
29 Muscles of hind legs
Figure 749 Ventrodorsal projection of abdomen. British Domestic Short Haired cat 8 years old, neutered female (same cat as left and right lateral recumbent projections of abdomen, Figures 745 and 747). (Approximately 90% of original size.)
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