Editing Lower limb (section)

== '''Venous system:''' ==

* '''Deep:'''
** Located beneath deep fascia      and accompany corresponding arteries
** Anterior and posterior      tibial -> popliteal -> femoral
** Femoral vein
*** Tributaries - GSV and       profunda femoris vein and circumflex femoral veins
** Popliteal vein
*** Formed from the union of       the two venae comitantes of the anterior and posterior tibial arteries
*** Receives SSV
* '''Superficial:'''
** The superficial system      collects blood from superficial tissues and skin and then routes it back      to the deep system for return.
** GSV, SSV and many      communications
** '''Great      saphenous vein'''      (GSV - also long saphenous vein)
*** Path:
**** Begins as the upward        continuation of the medial marginal vein of the foot, and courses        upward in front of the medial malleolus.
**** Runs behind the medial        border of tibia to the knee (together with saphenous nerve)
**** Hand's breadth behind        medial edge of patella
**** Posterior arch vein joins        it at or below the knee joint. In the vast majority of cases, the GSV        at calf level is anterior-dominant.
**** Spirals forward round the        medial convexity of the thigh
**** The GSV passes between        deep and superficial layers of fascia (see below diagram).
**** It ends (at the fossa        ovalis) by passing through the cribriform fascia covering the saphenous        opening (which lies about 3cm below and lateral to the pubic tubercle),        where it joins the femoral vein into its anteromedial side, 1-3cm below        the inguinal ligament (saphenofemoral junction).
**** '''External        pudendal artery'''        runs between GSV and CFV and is susceptible to injury
*** Structure:
**** It contains 7-20 valves,        mostly below knee level.
**** Longest vein in the body
*** Tributaries
**** Up to four tribs join the        GSV near the saphenofemoral junction:
**** '''Superficial        circumflex iliac'''
**** '''Superficial        (inferior) epigastric'''
**** '''Superficial        external pudendal'''
**** '''Deep        external pudendal'''
**** Can also see posteromedial        and anterolateral accessory branches
*** Fascial envelope: 60% have       type A, 30% type B, 10% type C (see below for diagram)
*** 8% have a lateral-dominant       system instead
*** Variant anatomy
**** Duplication of GSV
**** Some tributaries draining        directly into SFJ/CFV


* '''Small     saphenous vein'''     (SSV)
** Path:
*** Forms from the confluence       of the lateral aspect of the dorsal venous network of the foot (lateral       marginal vein of the foot)
*** Originates inferior and       posterior to the lateral malleolus, and ascends on the posterior aspect       of the calf between the gastrocnemius heads to the popliteal fossa.
*** It generally joins with the       popliteal vein within 5cm of the knee crease, however the confluence has       a variable location, and can be above-knee popliteal in 33%.
*** Note that SSV is intimately       associated with the sural nerve at the posterolateral aspect of the       ankle.
*** The SSV also lies within       its own fascial compartment and has 7-10 valves.
*** Lots of perforators
* '''Communicating     veins'''
** Cockett's perforators occur      at 3, 6 and 9cm above the medial malleolus, usually terminating in      posterior tibial veins
** Gastrocnemius veins emerge      from medial and lateral heads of gastrocnemius, and may join the      popliteal vein directly or merge with the SSV to form a common trunk then      enter popliteal.
** Intersaphenous (Giacomini)      vein courses up the posterior medial aspect of the thigh. It is often a      tributary of SSV
** Reticular veins are      thin-walled blue venules lying within the superficial compartment, often      connecting to telangiectasias
** Telangiectasias are dilated      venules, capillaries or arterioles 0.1 to 1.0mm in diameter. Arterial      telangiectasias are flat and red, while venous telangiectasias are raised      and blue.