Fig. 210.—Deep-seated lymphatic glands of the head and neck. The posterior portion of the lower jaw removed. P, pharynx; GRp, retro-pharyngeal gland; GC, deep cervical glands (cervical chain); NS, spinal nerve; NP, pneumo-gastric nerve; GCs, superior cervical nerve ganglion; NMi, inferior maxillary nerve.
Beginning with the head and fore quarters, the lymphatic apparatus comprises a subglossal, a preparotid, a subatloid, a prescapular and several prepectoral glands (Fig. 209).
None of these glands are very deeply placed, and all are easily accessible to palpation, provided their exact position is known and the animals are not too fat.
The subatloid is a little more difficult to detect, but in thin animals the tips of the fingers can easily be passed under the wing of the atlas so that the condition of the gland can be examined.
In a normal condition, any gland on being examined conveys a sensation of softness and elasticity of a special character which never varies. Palpation is painless.
When, however, the gland is diseased, palpation causes pain in the case of all acute affections. It may, indeed, be impossible to reach the glands, as they are buried sometimes in œdematous swellings of varying size. On the other hand, they may be painless on being touched, but swollen, hypertrophied, indurated, hardened or caseous.
The deep-seated glands of the fore portion of the body comprise the retro-pharyngeal and the cervical chain running along the posterior border of the trachea. Normally these glands cannot be examined (Fig. 210); but when the seat of certain morbid processes, they may be so enlarged as even to be readily visible. The larynx and pharynx are then displaced downwards, the depression between the head and upper extremity of the neck disappears, together with the depression known as the jugular furrow. Such deformities may be either perfectly symmetrical, as in lymphadenia, or (as is more commonly the case) asymmetrical, as in tuberculosis; and if inspection leaves any doubt, the glands may be further examined by palpation.
Fig. 211.—Lymphatic glands of the hind quarter. GG, Precrural lymphatic gland; GF, lumbar lymphatic; GP, popliteal lymphatic (deep-seated); GI, ischiatic lymphatic (deep-seated); GA, anal lymphatic (deep-seated).