▶ Previous Artlcle : #2-2. Functions of the Venous System

 

Anatomy of lower limb veins

 

Compared to the arterial system, the anatomy of the venous system is more complicated with widely variable passage. Therefore, familiarizing oneself with the anatomy of the venous system is quite a difficult task. However, it is necessary to be well-versed in the venous anatomy in order to diagnose venous diseases. Most venous diseases occur in extremities, especially lower limbs. Thus, for the sake of convenience, this article will focus on the anatomy of lower limb veins.

 

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The of venous system of the lower limbs can be largely divided into following three categories according to anatomy and function; 1) superficial, subcutaneous veins, 2) deep, intramuscular veins and 3) communicating veins and perforating veins.

Superficial, subcutaneous veins have sturdy walls with a thick elastic muscular layer. They function as a reservoir of blood and are located between superficial fascia and subcutaneous fat. Deep, intramuscular veins carry blood into the heart and lie alongside deep fascia. Perforating veins penetrate fascia and are perpendicular to the skin surface. Communicating veins connect two different points in the venous system on the surface of fascia and are parallel to the skin surface.

 

Greater Saphenous Vein (GSV)

 

In one extremity, two main superficial, subcutaneous veins form a pair. In lower extremities, this pair consists of the greater saphenous vein (GSV) and lesser saphenous vein. These superficial, subcutaneous veins penetrate fascia and communicate with deep, intramuscular veins through communicating veins. The GSV begins in the dorsal arch of the foot and is often used as cut down site for intravenous infusion. In other words, it begins in the medial malleolus of the foot, traverses the inner calf and thigh and enters the common femoral vein through fossa ovalis at the inguinal region. This area is called the sapheno femoral junction (SFJ). This area where the GSV joins the femoral vein lies medial to the femoral artery, generally 3cm lateral and 3cm inferior to the pubic tubercle. The GSV is easy to find as its location is relatively consistent in the joining area of the femoral artery and pubic tubercle.

The diameter of a vein is very important as it serves as a phlebologic parameter for selecting a treatment. According to the statistics of my hospital, an average diameter of a normal GSV is 5~8mm. If it is thicker than this, blood regurgitation can be suspected. The diameter is measured at about 1cm below the SFJ. As the diameter varies widely, I measure the thickness of the SFJ as well as sites 2-3cm below the SFJ and use the biggest measurement. The anatomical structure of the area where the common iliac vein within the pelvis joins the inferior vena cava has great clinical importance. Here the right common iliac artery crosses atop the right common iliac vein, suppressing the vein and causing venous stasis in the left lower extremity. This phenomenon contributes to the higher incidence of venous diseases such as phlebothrombitis in the left lower limb compared to the right lower limb.

The GSV receives five small venous tributaries within a few centimeters before its integration into the femoral vein. In principle, in traditional surgical treatment of varicose veins, stripping and ligation of the GSV as well as all venous tributaries are performed (crossectomy).

The five venous tributaries are listed below.

① external pudendal vein

② superficial epigastric vein

③ circumflex iliac vein

④ medical accessory saphenous vein

⑤ lateral accessory saphenous vein

In the lower extremity, the saphenous nerve and GSV run alongside each other and damage to the saphenous nerve during stripping of this vein may cause paresthesia in the corresponding area of the skin.

According to the statistics of my clinical practice, 47% of all patients undergoing varicose vein surgery presented valve anomaly in the SFJ of GSV. As such, the GSV requires close examination as the valve damage most frequently occurs in this vein. The superficial, subcutaneous vein GSV, deep, intramuscular vein, CFV (Common Femoral Vein), and femoral artery, as well as lymph ducts etc. traverse through the SFJ. Therefore, in some cases, the CFV, not GSV, requires stripping. This frequently causes lymph damage leading to edema and seroma, etc. The operating surgeon must identify the exact location, size and reflux characteristics, etc. with ultrasound prior to the procedure to prevent error.

 

-To be  continued-

 

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