Page 399 - Anatomy and Physiology of Farm Animals, 8th Edition

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(A) coronary groove (B)
Dorsal
VetBooks.ir Left longitudinal groove Dorsal caudal
blind sac

Dorsal
coronary
pillar
Caudal groove
Right longitudinal
pillar
Retic.

Ruminoreticular Cranial Ventral caudal Caudal
groove groove Ventral blind sac
coronary groove Reticular groove pillar
Right longitudinal groove

Ruminoreticular Ventral
fold coronary
Cranial pillar
pillar
Omasum

Abomasum

Figure 20-14. Detailed anatomy of the bovine stomach. (A) External anatomy from the left (top) and
the right (bottom). (B) Internal anatomy; grooves on the exterior of the stomach correspond to raised,
muscular ridges (“pillars”) on the interior of the stomach.

Ruminoreticulum that the milk will not be allowed to sour in
the forestomach.
Because of their functional and anatomic The reticulum is the most cranial com­
relatedness, the reticulum and rumen are partment of the forestomach. Its mucosa is
often collectively called the ruminoreticu- thrown up into intersecting ridges that
lum. The opening of the esophagus (the give the reticulum its common name, the
cardia) is about the level of the middle of “honeycomb.” Foreign objects such as wire
the seventh intercostal space, and it opens or nails that are swallowed typically will
into the dorsal space that is common to fall into and remain in the reticulum; con­
both the rumen and reticulum. The mucosa tractions of this part of the forestomach
in the region of the cardia forms two heavy may drive sharp objects through the wall of
muscular folds that together create a the stomach, leading to traumatic peritoni­
groove extending from the cardia to oma­ tis or hardware disease (see Chapter 17).
sum. This is the gastric groove (also called The location of the reticulum immediately
the esophageal or reticular groove). In caudal to the diaphragm places it opposite
nursing ruminants, the act of suckling ini­ the heart, with only the muscular dia­
tiates a reflex contraction of the muscular phragm between, so that these sharp
walls of the groove, transforming it from a objects may also be driven into pleural and
deep sulcus to a closed tube that connects pericardial spaces.
the cardia with the omasum. By this reflex, The reticulum and the rumen are
swallowed milk bypasses the ruminoretic­ divided ventrally by a thick, muscular
ulum and is instead delivered to the more ruminoreticular fold. The rumen extends
distal parts of the stomach; this ensures from this fold to the pelvis and almost