Ductus Deferens

The "ductus deferens" (also called the "vas deferens") is a muscular tube that begins at the lower end of the epididymis and passes upward along the side of the testis to become part of the spermatic cord. It passes through the inguinal canal, enters the abdominal cavity, and courses over the pelvic brim. From there, it extends back into the pelvic cavity, where it ends behind the urinary bladder. Near its termination, it becomes dilated into a portion called the "ampulla." Just outside the prostate gland, the tube becomes slender again and unites with the duct of a seminal vesicle. The fusion of these two ducts forms an ejaculatory duct, which passes through the substance of the prostate gland and empties into the urethra through a slit-like opening.