الفهرس 
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Abstract
The cecum is the proximal part of the large intestine, forming a dilated
pouch distal to the ileum and proximal to the colon and receives waste material
from the small intestine. There is a great deal of variation in the relative size of
the cecum between species. The dog’s cecum is a small, coiled organ while in
horse it is a very large fermentation chamber extending from the upper right
flank to the xiphoid cartilage of the sternum. Birds are different again; they
have a double cecum which appears to compensate digestively for the absence
of a significant colon.
(http://download.videohelp.com/vitualis/med/large_intestine.htm)
Most of mammalian herbivores have a relatively large cecum, hosting a
large number of bacteria, which aid in the enzymatic breakdown of plant
materials such cellulose. In many species, the cecum is considerably wider than
the colon. In contrast, obligatory carnivores, whose diets contain little or no
plant material, have a reduced cecum, which is often partially or wholly
replaced by the vermiform appendix. Over 99% of the bacteria in the gut flora
are anaerobes, but in the cecum, aerobic bacteria reach high densities
(Guarner and Malagelada 2003 and Sears, 2005).
The cecum of the dog is an irregularly twisted tube which is attached to
the ileum and ascending colon by short peritoneal folds (Nickel, Schummer
and Seiferle 1979). Yildiz, Arslan, COÞKUN, and Yildiz (2006) reported
that, the cecum, ascending colon, transverse colon, descending colon and
rectum are segments of large bowel. The cecum is usually described as the first
part of the large intestine. It has an irregular blunt apex and ends with the
ileocolic sphincter. The ascending colon and cecum are located at the
termination of the ileum. Moreover Miller, et al., (1993); Kumar (2004) and
Budras, Patrick, McCarthy, Fricke and Richter (2007) mentioned, that the
cecum is usually described as the first part of the large intestine, but this is not
true in the dog because the ileum, the terminal part of the small intestine,
communicated only with the colon, and the cecum exists as a diverticulum of
the proximal portion of the colon.
Miller et al., (1993) reported that, the communication of the cecum is with
the beginning of the ascending colon by means of the cecocolic orifice, this
opening lies approximately 1 cm from the ileocolic orifice. The cecocolic
sphincter is a specialization of the inner circular muscular coat which guards
the cecocolic orifice. The cecum is attached to the terminal portion of the ileum
by fascia and peritoneum throughout most of its length. Also Kumar (2004)
reported that, the cecum is attached to the distal portion of the ileum by an
ileocecal peritoneal fold, the blood vessels pass through this fold.
The cecum is extremely variable in size and forms in the living animal. It is
about 5 cm long and 2cm in diameter at its colic end. It is irregularly tapers to
the rather blunt apex, which is less than 1 cm in diameter and usually point
caudoventrally or is located transversely. When the cecum straightened, the
length of the cecum is over twice than attached (Miller et al., 1993; Kumar,
2004 and Yildiz et al., 2006). Nickel et al., (1979) reported that, the cecum of
the dog is 8-30 cm long and that of cat is 2-4 cm long.
The cecum is consists of apex, body and base, located to the right of the
median plane, and usually within the duodenal loop. It lies dorsal to and occasionally partly surrounded by the coils of the jejunum, ventral to the righ
transverse processes of the second to fourth lumbar vertebrae (Miller et al.
1993).
In addition Nickel et al., (1979) and Kumar (2004) stated that, the cecum
of the dog is located on the right side of the abdomen ventral to the transverse
processes of the second to the fourth lumbar vertebrae. The general direction o
the cecum is caudad, but its blind end is bent and often points craniad. The
cecum is related ventrally to the ileum and jejunum, dorsally to the righ
kidney, laterally to the descending duodenum and right lobe of the pancreas
caudally to the duodenum, and medially to the root of the mesentery.
Malla (2003) explained the cecum position on developmental o
embryological basis due to the arrest in the so called caudal migration of the
cecum to the right iliac region as seen in human being. Dyce, Sack and
Wensing (2002) stated that, the cecum is short though of varying length and
twisted. It is joined to the ileum by a short ileocecal fold and is oriented
crainocaudally, although its rounded blind end may finally point in any
direction. The cecum communicates with the ascending colon through the
cecocolic orifice adjacent to the ileal orifice. The cecum lies to the right kidney
dorsally, the descending duodenum and pancreas laterally, and the jejunum
ventrally. It lies below the second lumbar joint and thus is broadly level with
the most caudal part of the costal arch.