Epididymis

A long, coiled tube that runs along the back of the testis and connects the vasa efferentia (small tubes leading from the testis) to the vas deferens (the sperm duct leading to the urethra). Sperm cells, which are produced in the testis, mature as they pass slowly along the epididymis and are then stored in the seminal vesicles until ejaculation takes place. Disorders of the epididymis include epididymo-orchitis and epididymal cysts. Infection or injury can block the epididymis, which, if both testes are affected, may result in infertility.