Animal anatomy, histology, pathological anatomy

Internal inspection
To open the abdominal cavity, the corpse of cattle is strengthened in the left lateral position (Fig. 311). In this case, the voluminous stomach of ruminants, especially the rumen, will be located below, the intestines - in the right upper quarter of the abdominal cavity. You can strengthen the corpse in a semi-suspended state by the hind limbs, which facilitates the separation of the stomach, intestines and reproductive organs in females. Then the front right limb is removed along with the scapular cartilage and the back right limb up to the hip joint. In cows, the mammary gland is cut off, and in bulls, the prepuce with the penis is cut off to the root.



Fig. 311. Autopsy of ruminant corpses in the left lateral position.

The corpses of calves and small ruminants are fixed in the dorsal position.

In case of scar swelling (intravital or postmortem tympany), abdominal hydrops or peritonitis, the abdominal cavity is opened especially carefully.
To examine the abdominal cavity, the omentum is separated at the place of its attachment to the duodenum, along the S-shaped curvature, greater curvature of the abomasum, book and right groove of the rumen. The omentum is lifted by the rear free edge and cut off with a knife. The quantity and properties of adipose tissue are determined. After removing the omentum, the organs of the abdominal cavity, part of the small intestines, the right half of the large intestine and cecum, and the organs of the right half of the pelvic cavity are opened for inspection.
On the omentum and serous integument of the abdominal cavity in ruminants, thin-necked cysticercosis blisters with clear liquid and a large whitish head, the scolex, can be found. Check the position, relationship (anatomically correct, natural or otherwise) and appearance of the abdominal organs: the presence of feed impurities on the serous covers, adhesions, abscesses, foreign objects and connective tissue growths, which are often found in cattle with traumatic reticulitis in the mesh area, liver, diaphragm.
Extraction of internal organs.In cattle, the abdominal organs are removed before opening the chest cavity, except in cases where there is suspicion of traumatic pericarditis, pneumothorax, diseases of the lungs and pleura.
The stomach is removed first. To do this, two paired ligatures are applied to the initial part of the duodenum behind the bend (which lies superficially at the exit from the abomasum) and the intestine is cut between the two ligatures. In the area of ​​the right kidney (behind the S-shaped curvature), two more ligatures are placed on the duodenum and it is cut. After this, the corpse is turned on the right side, the connective tissue tissue between the scar and the dorsal wall of the abdominal cavity, the ligaments of the spleen with the diaphragm are dissected; After applying the ligature, the esophagus is cut, the stomach is removed along with the spleen. The spleen is separated, examined and, if there are intravital pathological changes, especially enlargements, examined primarily to exclude septic disease.
Depending on the condition, the intestines are removed in two ways: isolated thin and thick, or together.
When extracting the small and large intestines in isolation, two ligatures are placed on the ileum at the point where it flows into the cecum, the ileum is cut and separated from the mesentery of the small intestine. In this case, the mesenteric lymph nodes are dissected and examined. To remove the large intestine, the pancreas is dissected from the colon, a ligature is applied to the rectum in the pelvic cavity, the colon and cecum are separated to the root of the mesentery, which is cut along with the anterior mesenteric artery. If it is necessary to more fully examine the small and large intestines in their relationship (the presence of volvulus, intussusception, etc.) and the mesenteric lymph nodes in connection with the intestines, the small and large intestines are removed together. To do this, it is pulled up from the spine and the root of the mesentery is cut.
After this, the ligaments of the liver with the diaphragm and the right kidney are dissected and the liver with the pancreas and the S-shaped segment of the duodenum is removed.
The kidneys are separated along with the perinephric tissue and adrenal glands. The bladder of cows is separated along with the uterus. In bulls, it is removed after dissecting the lateral vesico-umbilical and medial ligaments and dissecting the adjacent peritoneum and connective tissue of the pelvis. The bladder and accessory sex glands are pulled up and cut at their root.
To extract the reproductive organs of females, the ovaries with the oviducts are separated, the wide uterine ligaments and the vesico-scarpicular ligament are dissected, the uterus with the bladder is pulled out of the pelvic cavity, cutting the peritoneum and connective tissue with a circular incision, and the vagina behind the cervix is ​​cut.
For a complete examination of the genitourinary organs, they are removed as a single complex along with the rectum.
Rib cage. Normally, there may be a small amount of cadaveric effusion in the chest. The presence of pus, fibrin, blood and blood clots, hydrocele, adhesions indicates pathological processes that arose during the life of the animal.
In cattle with traumatic pericarditis, along with inflammatory changes in other organs of the abdominal and thoracic cavities, up to 10–30 liters of purulent-fibrinous exudate can accumulate in the cardiac sac. The pericardium is significantly thickened, with purulent-fibrinous deposits and villous thickenings. The breast bone is opened with a longitudinal cut, assessing the condition of the bone tissue and bone marrow, the appearance of yellow bone marrow in obese cows. There may be rachitic bead-shaped thickenings in the costal cartilages, and in case of bone dystrophy in cows, there may be softening and resorption of the last ribs.
Organs of the thoracic cavity are usually removed together with organs of the oral cavity and neck as a single complex. In cattle, the lungs are connected to the diaphragm by a special ligament, which is cut when the lungs are removed.
For a more complete examination of the organs of the oral cavity in situ in cattle when they are affected by actinomycosis, part of the lower jaw is removed, for which all soft tissues in the cheek area (from the lips to the jaw joint) are separated and examined, the body of the lower jaw is sawed down and separated from the jaw joint .
Brain. After removing the soft tissue from the skull, it is examined and the cranial cavity is opened (Fig. 312).



Fig. 312. Cattle skull cutting lines.

To do this, make a transverse cut of the skull, the boundaries of which almost coincide with the upper edge of the ocular processes of the frontal bones, and two lateral cuts from the base of the same processes from behind through the frontal, parietal, temporal and occipital bones at the border of the upper edge of the occipital tubercles to the occipital foramen. The unfinished areas of the bones are cut with a bone holder or the hook of a hatchet handle. After removing the brain, the frontal sinus and nasal cavities are opened and examined, for which a longitudinal cut of the skull is made (the cut passes through the occipital, sphenoid, parietal, frontal, nasal bones), departing from the sagittal line by 0.5 cm to preserve and examine the nasal septum, and then they remove it too.

If the study of the brain is given less importance than the nasal and accessory cavities, the skull is sawed lengthwise, retreating 0.5 cm from the midline (in one direction or the other to preserve the nasal septum), in the longitudinal direction into two symmetrical halves.