To obtain the fullest information both hands should be used, one arm being passed over the neck and the fingers engaged behind the trachea. The operator may also stand in front of the animal, whose head should be lifted so that the points of the fingers can be thrust deeply inwards on either side of the trachea in the direction of the vertebral column.
In the posterior portion of the body the number of glands that can be examined is much smaller. The gland of the stifle, also called “gland of the flank,” is, so to speak, the only one which can readily be detected by examination or palpation. Nevertheless, in cases of lymphadenitis, tuberculosis of the glands, etc., it becomes easy to detect lymphatic glands in the loose fold of skin known as the flank. These glands are very small, and three in number. They are arranged in a triangle, one being much more prominent than the two others. In exceptional cases, little nodular glands, indistinguishable at ordinary times, may become hypertrophied. This is particularly true of the small glands in the neighbourhood of the last rib.
Fig. 212.—Lymphatic glands of the thoracic and abdominal cavities. T, Trachea; C, heart and pericardium; Bd, right bronchi; O, œsophagus; A, posterior aorta; VCp, posterior vena cava; R, rectum; VIe, external iliac vein; AIe, external iliac artery; GA, aortic lymphatic gland (anterior mediastinum); GM, mediastinal lymphatic glands (posterior mediastinum); GSL, sublumbar lymphatic glands (part of lumbar chain); GSS, subsacral lymphatic glands; GI, iliac lymphatic glands.
The retro-mammary glands need only be mentioned, but it is important to know that a deep-seated popliteal gland also exists above the semi-tendinosus and semi-membranosus muscle in the thickness of the muscles of the thigh; as also an ischiatic gland opposite the ischiatic notch, which can only be examined by internal palpation from the pelvis, and an anal gland situated deeply on the sides and in front of the sphincter ani.
With the exception of those of the pelvis and of the sublumbar region, the glands of the thoracic and abdominal cavity cannot be examined, but change in them is indicated under certain circumstances by clearly defined clinical symptoms, and moreover it is necessary to be able to detect changes in these glands on post-mortem examination.
In the thoracic cavity the lymphatic apparatus comprises the mass of the prepectoral glands, which extends into the anterior mediastinum between the first ribs (glands of the entry to the chest), the aortic lymphatic gland situated beneath the dorsal portion of the spine opposite the bifurcation of the aorta, and the lymphatic glands of the posterior mediastinum, one of which is relatively small and is lodged in the concavity of the posterior aorta, the other large, elongated and situated immediately above the œsophagus in front of its passage through the diaphragm.
In the abdominal cavity a sublumbar chain is found situated on the sides of the lumbo-sacral portion of the vertebral column, the mass of the subsacral lymphatic glands, and, at the entrance to the pelvis, extending on either side along the course of the external iliac arteries and veins and resting on the shafts of the iliac bones, the iliac glands.
All these glands are partly accessible to examination by the rectum.
Last of all, we may mention the gland situated on the hilum of the liver, the mesenteric glands, and the little lymphatic glands above the sternum.