The pampiniform plexus is a loose network of small veins found within the male spermatic cord.

The plexus begins in the scrotum with veins arising from the mediastinum testis, an area of connective tissue at the back of the testis. The veins of the plexus ascend along the spermatic cord at the front of the ductus deferens.

The pampiniform plexus helps regulate the temperature of the testes by acting as a “heat exchange” mechanism to cool down the blood. The arteries supplying the testes run through the plexus where the blood is cooled from abdominal arterial temperature to testicular temperature.

The anterior (front) section of the plexus comes together to form the internal spermatic vein, which passes through the inguinal canal (at the side of the groin area) and ascends into the retroperitoneum (a space in the abdominal cavity). The walls of the plexus veins house a complex muscle structure, which propels blood flow (against gravity) towards the left renal vein.

Male infertility or testicular pain may often be associated with a varicocele, which is an abnormal distension (enlargement) of the pampiniform plexus. Varicoceles are caused by retrograde (reversed) blood flow or impaired drainage of the testicular or internal spermatic vein. Varicoceles are the most common, treatable cause of male infertility.