Page 806 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Gastrointestinal system: 4.2 The lower gastrointestinal tr act 781

VetBooks.ir Gastrointestinal tract The thin, sharp, caudal edge of the spleen is pres-
auscultation and percussion
ent against the abdominal wall. The nephrosplenic
Auscultation is an important component of examina-
palpable dorsomedial to the spleen. The cranial mes-
tion of the GI tract; however, results must be taken ligament and posterior pole of the left kidney are
in the context of the entire clinical presentation enteric artery (CMA) can sometimes be felt caudally
and should not be overinterpreted. Multiple loca- and medially to the left kidney, running forward
tions should be evaluated. At a minimum, dorsal and along the aorta.
ventral quadrants should be auscultated over both
abdominal walls. The frequency and character of Right abdomen
borborygmi should be noted but patience is required The caecum, more particularly its ventral tenial
because of the intermittent nature of borborygmi, band, is felt running forward and down.
particularly sounds associated with caecal contrac-
tion. Decreased or absent sounds are indicative of Mid-abdomen
decreased intestinal motility, while increased sounds The small colon is characterised by the presence of
suggest hypermotility. Sounds of a fluid nature may faecal balls, sacculations and an antimesenteric tenial
be present in horses with colic or impending colitis. band. The bladder is found just cranial to the pelvic
Simultaneous auscultation and percussion should rim. The small intestine is usually not palpable.
also be performed to detect ‘pings’, which indicate In males, the inguinal rings should also be evaluated
underlying gaseous distension. for any abnormal content such as omentum or small
intestinal loops. In mares, the uterus and ovaries
Palpation per rectum should be palpated.
Evaluation of the intestinal tract p/r is a useful diag-
nostic tool that should be performed if possible on Potential abnormal findings
all horses with colic. The main limitation is that only Stomach
approximately 40% of the abdomen is palpable in an The stomach is not palpable; however, if excessive
average horse. Iatrogenic rectal tears can occur, but distension of the stomach is present, the spleen can
proper restraint (including chemical restraint) and be displaced caudally.
technique can greatly reduce the risk. The horse
should be handled by an experienced person and Small intestine
sedated (i.e. xylazine + butorphanol) if required. Small intestinal distension is characterised by the
Infusion of lidocaine (60 ml of 2% lidocaine in a presence of one or more loops of >5 cm diameter,
450 kg horse) into the rectum can reduce strain- smooth-surfaced viscera. It is not always palpable
ing. Ample lubrication should be used. Patience is when present, depending on the location of dis-
important and excessive force should never be used. tended intestinal loops. Palpation of the wall of the
Forcing the arm forward in a straining horse may small intestine should be performed to evaluate the
lead to a rectal tear. degree of oedema.
To reach a diagnosis by p/r examination it is
important to have a good knowledge of the normal Caecum
anatomy as well as an understanding of displacement Palpation of distinct contents within the caecum or a
and change that can occur in different pathologies. tight ventral tenial band running in a vertical plane
is indicative of caecal tympany or impaction. In the
Normal findings case of gas distension, the apex of the caecum may
Left abdomen be directed dorsally and the ventral tenial band may
The pelvic flexure is located cranially and ventrally be in an oblique or transverse position. With some
to the brim of the pelvis. It is knee-shaped, and large colon displacements, the caecum may not be
bands may be felt if there is some content within it. found in its normal location.