Testicles form in the abdomen during fetal development. During the final months of development, the testicles gradually descend into the scrotum. If your son has a retractile testicle, the testicle originally descended as it should, but then it didn't remain in place.
Signs and symptoms of a retractile testicle include the following:
- The testicle may be moved by hand from the groin into the scrotum and won't immediately retreat to the groin.
- It may spontaneously appear in the scrotum and remain there for a time.
- It may spontaneously disappear again for a time.
The movement of the testicle almost always occurs without pain or discomfort. Therefore, a retractile testicle is noticed only when it is no longer seen or felt in the scrotum.
The position of one testicle is usually independent of the position of the other one. For example, a boy may have one normal testicle and one retractile testicle.
Retractile testicle is different from undescended testicle (cryptorchidism). The undescended testicle is one that never entered the scrotum. If a doctor attempted to guide an undescended testicle, it would cause discomfort or pain.
When to see a doctor
During regular well-baby checkups and annual childhood checkups, your son's doctor examines your son's testicles to determine if they're descended and appropriately developed. If you believe that your son has a retractile or ascending testicle — or have other concerns about the development of his testicles — see his doctor. He or she will tell you how often to schedule checkups to monitor changes in the condition.
If your son experiences pain in the groin or testicles, see your son's doctor immediately.
An overactive muscle causes a testicle to become a retractile testicle. The cremaster muscle is a thin pouch-like muscle in which a testicle rests. When the cremaster muscle contracts, it pulls the testicle up toward the body.
The main purpose of the cremaster muscle is to control the temperature of the testicle. In order for a testicle to develop and function properly, it needs to be slightly cooler than normal body temperature. When the environment is warm, the cremaster muscle is relaxed; when the environment is cold, the muscle contracts and draws the testicle toward the warmth of the body. The cremaster reflex can also be stimulated by rubbing the genitofemoral nerve on the inner thigh and by extreme emotion, such as anxiety.
If the cremaster reflex is strong enough, it can result in a retractile testicle, pulling the testicle out of the scrotum and up into the groin.
Causes of an ascending testicle
A small percentage of retractile testicles can become ascending testicles. This means the once-movable testicle becomes stuck in the "up position." Contributing factors may be:
- Short spermatic cord. Each testicle is attached to the end of the spermatic cord, which extends down from the groin and into the scrotum. The cord houses blood vessels, nerves and the tube that carries semen from the testicle to the penis. If growth of the spermatic cord doesn't keep pace with other body growth, the "tight" cord may pull the testicle up.
- A problem with the normal path of a descending testicle. The testicles develop in the abdomen during pregnancy, then drop down into the scrotum. Sometimes part of the fetal structure fails to detach from the abdomen, resulting in an upward pull on the testicle.
- Scar tissue from hernia surgery. An inguinal hernia is caused by a small gap in the abdominal lining through which a portion of the intestines can protrude into the groin. Scar tissue following surgery to repair the hernia may limit the growth or elasticity of the spermatic cord.
Retractile testicles are not associated with any ill effects, aside from a greater risk of the testicle becoming an ascending testicle.