The epididymis is a tightly coiled tube that sits along the posterior aspect of each testicle, serving as the pathway through which sperm mature and are transported from the testis to the vas deferens. It consists of three segments: the head at the upper pole of the testis, the body along the posterior surface, and the tail at the lower pole. On scrotal ultrasound, the epididymal head is the most readily visible portion, typically appearing as a triangular or comma-shaped structure that is similar in echogenicity to, or slightly more echogenic than, the testis. Evaluating the epididymis is an important part of every scrotal ultrasound, as conditions like epididymitis, cysts, and spermatoceles commonly affect this structure.
Sonography Term