Short saphenous territory - Short saphenous vein - Accessory short saphenous vein
Duplications of the short saphenous vein are much less common
than duplications of the long saphenous vein. These duplicates
have a small diameter and are sometimes missed on an excessively
rapid ultrasound examination. Their parietal composition is
similar to that of the main short saphenous trunk, with a
linear wall of constant thickness. They travel parallel to
the short saphenous vein.
Their level of anastomosis with the deep network and their
site of transfascial penetration are variable and may differ
from those of the main short saphenous vein.
Two types of accessory short saphenous veins can be described
according to the depth of their course:

Accessory short saphenous veins situated in the same plane as
the main short saphenous vein (
Figure
86). These are more easily identified and more accessible
to treatment;

superimposed accessory saphenous veins, situated more deeply
than the main short saphenous vein (
Figure 87).
In this case, the main short saphenous vein has
a small caliber (2 to 3 mm) and travels in a fascial sheath
between the two gastrocnemius muscles. In the presence of reflux,
the suprafascial accessory saphenous trunk will become ectatic
(4 mm and more) and can then be mistaken for a solitary short
saphenous vein.
When these accessory veins have independent saphenopopliteal
junctions and when the main short saphenous vein is situated
below the popliteal crease, a "new saphenous" vein
may appear after stripping, as if a surgical procedure had
never been performed.

Further reading
Browse N.L., Burnand K., Thomas M. Diseases of the veins. Edward Arnold, Londres,
1988.