Veins of the lower extremity

# The Femoral Canal
- This short, conical medial compartment of the femoral sheath lies between the medial edge of the sheath and the femoral vein.
- The space allows for the femoral vein to expand during times of increased venous return from the lower limb.
- It contains a few lymph vessels, sometimes a deep inguinal lymph node, loose connective tissue, and fat.
- It is also the route by which the efferent lymph vessels from the deep inguinal lymph nodes pass to the external iliac lymph nodes.
- The canal is widest at its abdominal end, the femoral ring, and extends distally to the level of the proximal end of the saphenous ring.

# The Femoral Vein
- This large thigh vein ends posterior to the inguinal ligament, where it becomes the external iliac vein.
- It leaves the femoral triangle a little medial to the midinguinal point and the femoral artery.
- In the inferior part of this triangle, the femoral vein lies deep to the femoral artery.
- Within the femoral triangle, the femoral vein receives the profunda femoris and the great saphenous veins and other tributaries.

## The Femoral Vein in the Adductor Canal
- The femoral vessels enter the adductor canal where the sartorius muscle crosses over the adductor longus muscle, the vein lying posterior to the artery.
- The femoral artery and vein leave the adductor canal through the tendinous opening in the adductor magnus muscle, known as the adductor hiatus.
- As soon as the femoral vessels enter the popliteal fossa, they are called the popliteal vessels.

# The Popliteal Vein
- This vessel is formed at the distal border of the popliteus muscle by the union of the venae comitantes of the anterior and posterior tibial arteries.
- As it ascends through the popliteal fossa, the popliteal vein crosses from the medial to the lateral side of the popliteal artery.
- Throughout its course, it lies superficial to and in the same fibrous sheath as the popliteal artery.
- The popliteal vein ends at the adductor hiatus where it becomes the femoral vein.
- The small saphenous vein pierces the roof of the popliteal fossa and drains into the popliteal vein. The other tributaries of the popliteal vein correspond with the branches of the popliteal artery.

# The Small Saphenous Vein
- This lateral superficial vein begins posterior to the lateral malleolus.
- It is formed by the union of veins arising from the lateral part of the dorsal venous arch, the dorsum of the fifth digit (little toe), and the lateral edge of the foot and sole.
- The small (short) saphenous vein passes along the lateral side of the foot with the sural nerve and ascends along the lateral side of the tendo calcaneus.
- This vein passes on the deep fascia between the two heads of the gastrocnemius muscle to the popliteal fossa.
- It has several communications with the great saphenous vein on the medial side of the leg.
- Before piercing the popliteal fascia just inferior to the knee flexion crease, the small saphenous vein frequently gives off a branch that unites with another vein to form the accessory saphenous vein.
- When present, this vein becomes the main communication between the great and small saphenous veins.
- The small saphenous vein has several valves.

## The Small Saphenous Vein in the Popliteal Fossa
- In the popliteal fossa, the small saphenous vein usually perforates the deep popliteal fascia and usually ends in the popliteal vein.
- Sometimes, it ends in the great saphenous vein or in one of the superior gluteal veins.

# The Great Saphenous Vein
- This is the largest vein and the longest in the body.
- It ascends from the foot to the groin in the subcutaneous connective tissue.
- The great (long) saphenous vein begins at the medial end of the dorsal venous arch of the foot and passes anterior to the medial malleolus of the tibia, where it is accompanied by the saphenous nerve.
- It then ascends obliquely across the inferior third of the tibia to the medial aspect of the knee.
- Here it lies superficial to the medial epicondyle, about a hands-breath or 10 cm posterior to the medial border of the patella.
- From here, it ascends superolaterally to the saphenous opening in the deep fascia and enters the femoral vein.

# The Superficial Veins of the Lower Extremity
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# The Deep Veins of the Lower Extremity
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