Part 193

The =prescapular lymph glands= are situated at the anterior border of the anterior deep pectoral muscle undercover of the trapezius and omo-transversarius.

The =prepectoral lymph glands= are reddish in color and usually three in number. The largest is placed centrally under the trachea; the others are situated on the brachial vessels as they turn around the first rib.

The =axillary lymph glands= are usually absent, but very small nodes may be found near the insertion of the latissimus dorsi. Cubital glands are not present.

FIG. 484.—STOMACH AND PART OF INTESTINE OF PIG, SPREAD OUT.

a, Pyloric portion of stomach; b, duodenum; c, jejunum; d, cæcum; e, f, colon; g, pancreas; h, epiploic foramen (of Winslow); i, portal vein; k, hepatic lymph glands; l, gastric lymph glands; m, œsophagus. (After Edelmann.) ]

The =thoracic lymph glands= comprise: (1) a gland of considerable size on the first segment of the sternum; (2) about half a dozen reddish glands along the upper face of the thoracic aorta; (3) several glands along the lower face of the trachea; (4) the =bronchial lymph glands=; one of these lies on the bifurcation of the trachea and another at the apical bronchus of the right lung (Fig. 371).

The =lumbar lymph glands= are scattered along the abdominal aorta and the vena cava. Those placed near the hilus of the kidney are often designated =renal=.

The =internal iliac lymph glands= are rounded and relatively large. They comprise: (1) three or four glands situated on and between the origin of the circumflex iliac and the external and internal iliac arteries; (2) a gland in the angle of divergence of the internal iliac arteries.

The =external iliac lymph glands= are small, two or three in number, and lie in front of the circumflex iliac vessels near the point of the hip.

The visceral lymph glands of the abdomen comprise:

1. =Gastric lymph glands= on the lesser curvature of the stomach.

2. Several small =hepatic lymph glands= along the portal vein.

3. An elongated =splenic lymph gland= on the splenic vessels near the dorsal end of the spleen.

4. A series of =mesenteric lymph glands= situated along the anastomotic arches formed by the vessels of the small intestine.

5. Several =cæcal lymph glands= situated along the first part of the cæcal vessels.

6. Two series of =colic lymph glands= which accompany the arteries of the spiral part of the colon, and are exposed by separating the coils of the bowel. Small glands are placed in the colic mesentery and above the rectum.

7. The =anal lymph glands= are situated on either side on the retractor ani.

A small =ischiatic lymph gland= is found on the sacro-sciatic ligament near the lesser sciatic notch.

The =precrural lymph glands= are situated on the aponeurosis of the external oblique below the external angle of the ilium.

The =superficial inguinal lymph glands= are situated behind the external inguinal ring. No deep inguinal lymph glands are present.

The =popliteal lymph glands= are small normally and may escape notice.

A few nodules occur in front of the distal part of the tendo Achillis.

CIRCULATORY SYSTEM OF THE DOG

THE PERICARDIUM AND HEART

The =pericardium= is attached to the sternal part of the diaphragm by a fibrous band, and is connected with the sternum only by the mediastinal pleura.

The =heart= is almost globular in form, the apex being much blunter than in the other animals, and marked by a notch. Its long axis is almost parallel with the sternum and the apex (covered by the pericardium) is directed against the sternal part of the diaphragm. Its weight averages about 0.8 to 1 per cent. of the body-weight.

The base extends forward to a transverse plane through the lower ends of the third pair of ribs. The apex lies opposite the sixth costal cartilage in expiration. On the right side the pericardium is in direct contact with the chest-wall over a narrow triangular area (base anterior) from the fourth to the sixth intercostal space inclusive. On the left side the area of contact is smaller and is at the fourth, fifth, and sixth cartilages.

The two coronary arteries may arise by a common trunk. Each divides into circumflex and descending branches. The left artery is twice as large as the right one.