Lymph flow and lymph protein concentration in the skin and muscle of the rabbit hind limb.

1. Three lymphatic beds have been found in the rabbit hind limb:(i) the lymph from the foot and ankle drains into lymphatics which run with the deep veins to the popliteal node;(ii) the superficial lymphatics of the medial skin from mid-calf to the groin enter the inguinal node while those of the lateral skin drain into the popliteal node;(iii) the lymph draining the muscles collects in vessels which do not enter the popliteal node but join the femoral lymphatic post-nodally.2. The lymphatic system of the hind limb is regionalized so that lymph from a specific area enters the popliteal node in one specific lobe and no other.3. By cannulating the femoral lymphatic and ligating the post-nodal lymph vessel close to the point at which it leaves the node it was possible to collect pure muscle lymph.4. The mean muscle lymph flow was 21 mul./100 g.min whilst the skin lymph flow was 240 mul./100 g.min. The mean protein concentration of muscle lymph was usually somewhat higher than that of skin lymph.5. After nerve stimulation there was an increase in muscle lymph flow but no increase in protein concentration.6. After a mild thermal injury there was no change in muscle lymph flow or its protein concentration, but there was an enormous increase in the leakage of lactic dehydrogenase indicating considerable cellular injury. On the other hand a significant increase in both protein concentration and flow of skin lymph occurred after thermal injury.