Ultrasound of the Acute Scrotum

Phebe Chen, MD, Susan John, MD


Appl Radiol. 2006;35(3):8-17. 

In This Article


The testicles and associated structures are located within the scrotum, formed by fusion of three fascial layers and divided by a median septum.[1] The septum is contiguous with the dartos muscle underneath the scrotal skin. The tunica vaginalis is a potential space formed from the processus vaginalis, an outpouching of the fetal peritoneum that descends into the scrotum along with the testis. An inner visceral layer covers the testis and epididymis, and an outer parietal layer lines the scrotum. The layers join at the posterolateral aspect of the testis where it attaches to the scrotal wall. The tunica albuginea forms a dense capsule around the testis, and a reflection of this capsule along the posterior border (the mediastinum testis) runs along the superior inferior axis of the testis. The mediastinum divides the testis into lobules and serves as a conduit through which the blood vessels, lymphatics, and spermatic tubules enter and leave the testis. The epididymal head is located superior to the testis, while the body and tail run posterior to the testis. The efferent ducts converge and, from the epididymal tail, become a single vas deferens, which continues in the spermatic cord. The spermatic cord also contains the testicular, cremasteric, and deferential arteries, pampiniform plexus, nerves, and lymphatics.[1,2,3] Four testicular appendages, remnants of embryonic ducts, include the appendix testis, appendix epididymis, vas aberrans, and the paradidymis; 92% of males have an appendix testis, and 34% have an appendix epididymis.[4]

The main blood flow to the testicle is via the testicular artery, with branches off the deferential and cremasteric arteries. These arteries course through the spermatic cord, along with their corresponding veins and nerves. The testicular artery pierces the tunica albuginea, forming capsular arteries that, in turn, form recurrent rami that course centrifugally toward the mediastinum. In 10% to 50% of normal testes, a single transmediastinal artery can be seen unilaterally running directly within the mediastinum and coursing in an opposite direction from the recurrent rami.[1,2,5]


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