The great saphenous vein (GSV, alternately "long saphenous vein"; ) is a large, subcutaneous,

superficial vein Superficial veins are veins that are close to the surface of the body, as opposed to deep veins, which are far from the surface. Superficial veins are not paired with an artery, unlike the deep veins, which are typically associated with an arte ...

of the leg. It is the longest vein in the body, running along the length of the lower limb, returning blood from the

foot The foot ( : feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made ...

, leg and

thigh In human anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone ...

to the

deep Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary), C ...

femoral vein at the

femoral triangle The femoral triangle (or Scarpa's triangle) is an anatomical region of the upper third of the thigh. It is a subfascial space which appears as a triangular depression below the inguinal ligament when the thigh is flexed, abducted and laterally rot ...

Structure

The great saphenous vein originates from where the dorsal vein of the

big toe Toes are the digits (fingers) of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being ''digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being ''plant ...

(the hallux) merges with the

dorsal venous arch of the foot The dorsal venous arch of the foot is a superficial vein that connects the small saphenous vein and the great saphenous vein. Anatomically, it is defined by where the dorsal veins of the first and fifth digit, respectively, meet the great saphen ...

. After passing in front of the

medial malleolus A malleolus is the bony prominence on each side of the human ankle. Each leg is supported by two bones, the tibia on the inner side (medial) of the leg