A varicocele is the abnormal dilation and tortuosity of the veins in the pampiniform plexus that run along the spermatic cord into the scrotum. The spermatic cord provides nourishment through the blood vessels and contains nerves and lymph glands as well as the vas deferens. Varicoceles are reported to be found in 15% of all males. They are found to be the cause of infertility in 30-40% of the cases. The varicoceles develop when a defective valve in the vein allows the normal one-way flow of blood to back up into the abdomen. Blood then flows from the abdomen into the scrotum where a hostile environment for sperm development is created. Most varicoceles develop slowly and do not show symptoms. Some are large and visible as twisting veins in the scrotal sac. These veins disappear when lying down and the valsalva maneuver (bear down or cough) is used to demonstrated their filling distention.

They are more common on the left side, but do also occur bilaterally. The right internal spermatic vein drains directly into the inferior vena cava, whereas the left internal spermatic vein drains into the left renal vein at a 90-degree angle. This angle prevents the formation of a valve. As a result, 85-99% of the varicoceles are left-sided and only 1% are bilateral.

Varicoceles may cause infertility because they are associated with low sperm counts and decreased mobility. Sonographically they appear as an extratesticular collection of tortuous tubular structures.

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