The small saphenous vein starts at the lateral end of the dorsal venous arch of the foot and passes behind the lateral malleolus to join the popliteal vein in the popliteal fossa. This termination is very variable. The high termination occurs in 33 percent of cases; in this variation, the small saphenous vein passes up the posterior surface of the thigh (persistent postaxial vein; Giacomini vein) and either joins the GSV or terminates in muscle veins. The low termination occurs in about 9 percent, the small saphenous vein then joining gastrocnemius veins in the calf.
The paired gastrocnemius veins usually join the small saphenous vein close to its termination. Occasionally they join the popliteal vein directly, close to the saphenopopliteal junction. Incompetence of the gastrocnemius vein valves and reflux results in calf swelling and discomfort, which can be relieved by ligating these veins.
It is important to realize that the small saphenous vein perforates the deep fascia in the lower or middle third of the calf and lies deep to the deep fascia, between the bellies of gastrocnemius, until it joins the popliteal vein in the popliteal fossa. This feature of the small saphenous vein is described incorrectly in most anatomical textbooks and failure to appreciate this point results in many inadequate operations.
Ulceration on the lateral surface of the ankle is almost always associated with incompetence of the small saphenous vein. The great and small saphenous veins have relatively thick muscle coats, but the walls of their tributaries are thin and more likely to dilate and become varicose.
The perforating veins are those veins, other than the long and short saphenous, which penetrate the deep fascia, passing from superficial to deep. Between 50 and 100 unimportant indirect perforating veins enter the muscles before joining the deep veins. These are not normally important to calf muscle pump function, but may dilate and become haemodynamically significant following deep vein thrombosis, recanalization and reflux.
There are normally three direct perforating veins on the medial surface of the leg and ankle, and one or two laterally. The medial perforating veins communicate with the posterior arch vein, not the GSV itself. Each perforating vein contains a valve which directs blood from superficial to deep. An easy way to remember their positions is that the lowest lies behind the medial malleolus, the next a hand's-breadth above this, and the most proximal another hand's-breadth higher.
The direct calf and ankle perforating veins drain the skin over the medial and lateral malleoli by networks of venules and small veins at the distal end of the posterior arch vein; these dilate under increased venous pressure to form the 'ankle venous flare' or 'corona phlebectatica'. The medial and lateral ankle skin, the 'ulcerbearing area' of the leg, is not directly drained by either the long or small saphenous vein. The GSV does, however, communicate with the medial perforating veins through the inframalleolar vein(s) and the distal GSV also communicates with the plantar veins through the dorsal venous arch of the foot and the transmetatarsal veins.
The malleolar venous network which dilates to form the visible 'ankle venous flare' or 'corona phlebectatica' therefore communicates with the deep system by two routes: directly to the posterior tibial vein through the calf perforating veins; and indirectly through the plantar veins by way of the dorsal venous arch. Incompetence of a perforating vein valve results in high pressure in, and dilatation of, the malleolar venules, which results in the ankle venous flare.
Calf perforating vein incompetence and an ankle flare are common precursors of venous ulceration; other, more proximal, perforating veins are less often incompetent, and are usually related to primary varicose veins.
The foot perforating veins join the plantar veins (distal deep veins) to the dorsal venous arch, which joins the distal long and small saphenous veins. They are therefore able to transmit the high venous pressures in incompetent deep veins to the distal GSV and, by way of the inframalleolar veins, to the malleolar veins.
The Hunterian perforators form communications between the GSV in the lower third of the thigh and the superficial femoral vein in the subsartorial ('Hunter's') canal. Peroperative retrograde saphenography in a series of 60 patients showed at least one Hunterian perforator in 87 percent of 80 saphenograms.
Seventy percent of incompetent thigh perforating veins are found in the region of the adductor canal13 and their incompetence is a common cause of recurrent varicose veins of the GSV following saphenofemoral ligation without stripping. Other, less common, perforating veins are Boyd's perforator,which joins the great saphenous to the posterior tibial vein on the medial surface of the upper calf at the level of the tibial tubercle, and occasionally a similar perforating vein is found on the lateral surface of the upper calf.
Our website is not responsible for the information contained by this article. Articleinput.com is a free articles resource thus practically any visitor can submit an article. However if you notice any copyrighted material, please contact us and we will remove the article(s) in discussion right away.
Note: This article was sent to us by: Karen Pean at 02182011
1. Clinical evaluation in humans
© 2009 ArticleInput.com.