Sperm held in the epididymis eventually drain into the vas deferens (vas DEH-fuh — renz), a long, thin duct that travels up through the scrotum inside the spermatic cord. The vas deferens is close to the surface of the scrotum along this route, which makes the common male sterilization procedure, vasectomy (vuh-SEK-tuh-mee), relatively simple. (Vasectomy is described in Chapter 10.)
The spermatic cord exits the scrotal sac through the inguinal canal, an opening that leads directly into the abdominal cavity. From this point the vas deferens continues its upward journey along the top of the bladder and loops around the ureter, as shown in I Figure 4.6. (This pathway is essentially the reverse of the route taken by the testis during its prenatal descent.) Turning downward, the vas deferens reaches the base of the bladder, where it is joined by the excretory duct of the seminal vesicle, forming the ejaculatory duct.
chapter 4
I Figure 4.6 Male sexual anatomy: A cross-section side view of the male reproductive organs.
The two ejaculatory ducts (one from each side) are very short, running their entire course within the prostate gland. At their ends they open into the prostatic portion of the urethra (yoo-REE-thruh), the tube through which urine passes from the bladder.