General

The lymph nodes of the abdominal and pelvic cavities can be divided into the parietal (wall) lymph nodes located on the abdominal and pelvic walls, and the visceral (organ) lymph nodes located on the abdominal organs (viscera).

Almost all the parietal lymph nodes are located near the abdominal aorta and the caudal vena cava, as well as their respective terminal branches. When the lymph nodes are located cranial to the deep circumflex iliac artery, and lie on the aorta and cranial vena cava, they are termed the lumbar aortic lymph nodes (Lnn. lumbales aorticae), while nodes located caudal to the deep circumflex iliac artery in the area of ​​the terminal division of the aorta and caudal vena cava have so far been grouped under the general term of iliac lymph nodes (Lnn. iliaci) (Ellenberger-Baum [18], Chauveau-Arloing [15]).

However, because the lymph nodes in this group have different afferent drainage areas, I will divide them into 2 groups: the medial iliac lymph nodes (Lnn. iliaci mediales), which consist of a lymph node on the right and left sides between the point of origin of the deep circumflex iliac artery and the external iliac artery, and the hypogastric ^[1]lymph nodes (Lnn. hypogastricae), now termed the internal iliac lymph nodes (Lnn. iliaci interni), which are located at the angle of division of the aorta between the two hypogastric arteries (currently termed the internal iliac arteries). The iliac lymph nodes correspond to the medial iliac lymph nodes of cattle, while lymph nodes corresponding to the lateral iliac lymph nodes in cattle are not observed in dogs. The hypogastric lymph nodes correspond to the sacral hypogastric lymph nodes in cattle (see Baum [6], page 3). I could not find any lymph nodes in the dog that were comparable to the lumbales propriae lymph nodes located between the transverse processes of the lumbar vertebrae of cattle. Additional parietal lymph nodes include the sacral lymph nodes and the deep inguinal lymph node.

The sacral lymph nodes are found as a continuation of the hypogastric lymph nodes and are located on the dorsolateral wall of the pelvic cavity. They are divided into 2 groups: the medial sacral lymph node (Ln. sacralis medialis), located on the medial sacral artery, and the lateral sacral lymph node (Ln. sacralis lateralis), located on the lateral pelvic wall, lateral to the hypogastric artery and vein (internal iliac artery and vein). The deep inguinal lymph node (Ln. inguinalis profundus) is the only parietal lymph node that lies on the lateral abdominal wall.