Lymph Vessels of the Skin of the Pelvic Limbs and Tail

The lymph vessels of the skin of the pelvic limbs and the tail (Figure 13) drain to the medial iliac lymph node, the superficial inguinal lymph nodes, the medial femoral lymph node, and the popliteal lymph node.

A. Skin of the Pelvis

The lymph vessels of the skin of the pelvis drain to the medial iliac lymph node (from the cranial two-thirds to three-quarters of the pelvic area), and to the superficial inguinal lymph nodes (from the caudal one-quarter to one-third of the pelvic area). The latter lymph vessels (Figure 13: 8) run to the ischial tuberosity and accompany the lymph vessels draining the skin of the tail around the ischial tuberosity to the medial surface of the thigh, travelling along it to the superficial inguinal lymph nodes.

b. Skin at the Base of the Tail

The lymph vessels of the skin at the base of the tail drain to the medial iliac lymph node, and the lymph vessels of the skin from the rest of the tail drain to the superficial inguinal lymph nodes, turning ventrally around the medial part of the ischial tuberosity (Figure 13: 8⁵).

c. Skin of the Lateral Thigh

The lymph vessels of the skin of the cranial half of the lateral thigh (Figure 13: 8⁷) course around the cranial border of the thigh muscles and drain to the superficial inguinal lymph nodes. The lymph vessels of the skin of the caudal half of the lateral thigh (Figure 13: 8⁶) also drain to the superficial inguinal lymph nodes; most of the vessels wrap around the caudal border of the thigh to the medial side, whereas a smaller number of vessels accompany the lymph vessels of the skin of the cranial half of the lateral thigh. It is not uncommon for one of the lymph vessels of the skin on the lateral side of the thigh to merge with the lymph vessels of the skin of the pelvis, which drain to the medial iliac lymph node (Figure 13: 14). Lymph vessels of the medial side of the thigh drain to the superficial inguinal lymph nodes, and if a medial femoral lymph node is present, some of the vessels will additionally drain into this lymph node.

d. Skin of the Lateral Side of the Stifle Joint

The lymph vessels of the skin on the cranial half of the lateral side of the stifle joint (Figure 13: 8⁸) curve around the cranial border of the thigh to drain into the superficial inguinal lymph nodes, while the lymph vessels of the skin of the caudal half of the lateral stifle drain into the popliteal lymph node (Figure 13: 5). The lymph vessels of the skin of the medial side of the stifle joint drain to the superficial inguinal lymph nodes, as shown in Figure 13. If a medial femoral lymph node is present (Figure 13: t), some of these lymph vessels will drain to it.

e. Skin of the Tarsus

The lymph vessels of the skin of the lateral side of the tarsus drain to the popliteal lymph node (Figure 13: 5), those from the skin on the medial side drain to the superficial inguinal lymph nodes (as shown in Figure 13), and those from the skin on the cranial and caudal sides drain to both lymph node groups. If a medial femoral lymph node (Figure 13: t) is present, some of the lymph vessels that otherwise drain to the superficial inguinal lymph nodes will instead drain into it.

f. Skin of the Metatarsus and Toes

The lymph vessels of the skin of the dorsal and medial sides of the metatarsus and toes travel first to the cranial side of the tarsus: from there, most of the lymph vessels travel over the lateral side of the lower leg to the popliteal lymph node (Figure 13: 5), while 1 or 2 of the lymph vessels (as shown in Figure 13: 17’) curve to the medial side of the lower leg and join with the lymph vessels draining to the superficial inguinal lymph nodes. If a medial femoral lymph node (Figure 13: t) is present, some of the lymph vessels usually drain to it first. Some of the lymph vessels of the skin of the lateral metatarsus and toes travel over the caudolateral border of the tarsus to the popliteal lymph node (Figure 13: 5), while others curve towards the cranial side of the tarsus (Figure 13: 8⁹) and join the lymph vessels mentioned above, so that 1-2 lymph vessels from the lateral side of the metatarsus will drain to the superficial inguinal lymph nodes.

Some of the lymph vessels of the skin of the plantar side of the metatarsus and toes join with the lymph vessels draining the skin of the lateral side, while others join the lymph vessels draining the skin of the medial side.