Testicular artery

Origin and course

The testicular arteries originate from the abdominal aorta, usually at the L2-L3 vertebral levels, just distally to the origin of the renal arteries. They descend through the pelvis by coursing inferolaterally and over the anterior surface of psoas major muscle, superficial to the genitofemoral nerve and ureter on each side. 

The left testicular artery reaches the pelvis by passing posterior to the descending colon, left colic artery and inferior mesenteric vein. While the right testicular artery passes posterior to the ileocolic and middle colic arteries and the distal ileum, and anterior to the inferior vena cava. They both enter the same sided deep inguinal ring and continue towards the testes through the spermatic cord.

Within the spermatic cord, the testicular artery is wrapped by the pampiniform venous plexus. This arrangement of the venous and arterial vessels creates a countercurrent exchange system, in which the heat of the arterial blood passes to the venous blood. This way, the arterial blood for the testes is 2-4°C cooler, i.e. 34-36°C, which is an optimal temperature for proper spermatogenesis.

Each testicular artery reaches the posterior margin of the ipsilateral testis near its inferior pole. It enters the mediastinum testis and splits into two terminal branches that enter the tunica vasculosa of testis and supply the testicular lobules.

Branches and supply

The testicular artery gives off two sets of collateral branches during its course;

• Ureteric branches in the abdomen, which contribute to the blood supply of the ureters
• Epididymal branches on its way through the spermatic cord, which contribute to the supply of the head, body and tail of the epididymis

The two terminal branches of the testicular artery arise in the tunica vasculosa of testis. Namely, they are the superior and inferior polar (segmental) branches. These branches course towards the superior and inferior poles of testis, respectively. Along the way, they give rise to the smaller centripetal arteries that enter and supply the testicular parenchyma. 

The branches of the testicular arteries anastomose with the branches of the cremasteric arteries and arteries to ductus deferens. Most commonly, the superior polar branch anastomoses with the artery to ductus deferens, while the inferior polar branch anastomoses with the branches of the cremasteric artery. 

Anatomical variations

The testicular arteries exhibit a certain degree of terminal branching variations. In about 15% of men, the artery has only one terminal branch; the superior polar branch, which after giving off the centripetal branches for the upper half of the testis, descends towards the inferior pole giving off the branches for the lower half of the testis. In around 8% of men, the testicular artery terminates by trifurcating into superior, middle and inferior segmental arteries.