The venous pump of the human foot

Pressures in the flexor digitorum muscle, posterior tibial and anterior tibial muscles and subcutaneous pressure in the lower leg were recorded in 18 volunteers with a non-infusion technique. The venous plexus of the sole of the foot was compressed by a pneumatic foot pump. Activation of this device creates oscillations of intramuscular and subcutaneous interstitial fluid hydrostatic pressure in the lower leg. The mechanism for this is explained by intermittent passive muscle stretch. The interstitial fluid pressure decreased following active muscle contractions during venous stasis of the limb, but not following activation of the pneumatic pump. Although the pneumatic foot pump may on theoretical grounds be useful in early treatment of postoperative and post-traumatic oedema of the leg, complementary studies are necessary to establish its effectiveness.