Veterinary Clinical Medicine-I (General and Systemic)

PROJECTION FIELD OF THE RETICULUM

FIG 11.

Percussion for sensitivity to pain

FIG 12.

o = No reaction

o = Slight

o = Definite reaction

Omasum

• Omasum is located to the right of the rumen and reticulum, dorsally and forwards by liver and diaphragm. It is close to the right abdominal wall behind lung line. Percussion field which is mostly easy to find is located in a semicircle from a hand’s breath above the costal arch, limits hindwards by 10^th rib or 10^th inter-costal space. The percussion field of omasum is on the right side between 7^th & 10^th ribs. This percussion sound gives clear gas tone, a little more dull, heavier than the lung tone.
• The omasum field becomes smaller in chronic diarrhea and functional disorders like stenosis between reticulum and omasum or when it has forced away from the chest wall. In pyloric stenosis the omasal field become larger. Auscultation at the centre of the omasal field may not succeed in picking up the rustling sound made by omasal contraction which is synchronous with reticular contraction because of louder sounds made by other stomach compartments. Fluid sounds may be heard instead of rustling sound during anterior functional gastric stenosis.
• Pain percussion will be helpful in detecting the omasal impaction.

Abomasum

• Abomasum is occupying most of the hypochondriac region and lies on the floor of the abdomen near the median plane. The fundus or anterior blind sac of the abomasums is located in the xiphoid region in close proximity to the reticulum. The pylorous joins the duodenum at the ventral aspect of the right ninth or tenth rib. Direct physical examination of the abomasums in the adult bovine is limited by thick tense ventral abdominal muscle.
• When the abomasums is displaced to the left, it’s gas content gives an obliquely oval region of tympanic sound half way up the abdominal wall, this extends from the lung field to the costal arch or even beyond it. The animal may show signs of discomfort when this area is percussed forcefully with the aid of plexor and pleximeter.
• Similar findings are observed when the abomasums is displaced to the right, with a tympanic sound extending from the small area of liver dullness to an area of almost complete dullness along a horizontal.

Other types of percussion

• Tactile percussion: It is the combination of palpation and percussion. It is practiced by placing the index finger on the back of hammer. It is commonly designated the sense of resistance felt by the pleximeter / finger during percussion and the sense of resistance is greater in areas that are dull and greatest when there is flatness. This technique will provide valuable information in regard to the boundaries and consistency of otherwise unavailable organs or part.