Structures within the abdomen or abdominal wall can be the source of stomach discomfort, according to the American College of Gastroenterology. But structures outside the abdomen--such as tissues in the chest, back and pelvis--can also cause stomach pain or the perception of stomach pain. Certain conditions may be responsible for pain, specifically in the lower right side of the abdomen.
Appendicitis
Appendicitis can cause lower right abdominal pain. According to the National Institute of Diabetes and Digestive and Kidney Diseases, appendicitis is a painful swelling and infection of the appendix. The appendix is a small, finger-shaped pouch that projects outward from the large intestine on the lower right side of the abdomen. It is considered a vestigial organ, that is, an organ that has no apparent purpose, though at some point during the evolutionary process, it may have performed an important function.
If the appendix's lumen or inside is blocked, mucus that usually passes through the appendix can accumulate and cause infection or appendicitis. Feces, parasites or growths are common causes of a blocked appendix. The NIDDK states that common signs and symptoms associated with appendicitis include aching pain that begins around the navel and grows sharper over time, pain that shifts from the navel to the lower right abdominal quadrant, nausea and vomiting, and loss of appetite.
Ectopic Pregnancy
An ectopic pregnancy can cause pain in the lower right quadrant of the abdomen. MedlinePlus states that an ectopic pregnancy occurs when a fertilized egg becomes embedded in tissue outside the womb or uterus. Tissues outside the uterus cannot support the growth and development of a fetus. Ectopic pregnancies usually occur in the fallopian tubes--the tubes that carry eggs from the ovary to the uterus--although they can also occur in the ovary, stomach area or cervix.
Possible causes of an ectopic pregnancy include scarring of the fallopian tubes by a previous ectopic pregnancy, infection or surgery. Hormonal factors, birth defects of the fallopian tubes and smoking can also cause blockages in the fallopian tubes. Common signs and symptoms associated with ectopic pregnancy include pain in the lower abdomen on the affected side, abnormal vaginal bleeding, breast tenderness, nausea and loss of menses or a period.
Testicular Torsion
Testicular torsion can cause lower right abdominal pain. According to MayoClinic.com, testicular torsion occurs when the spermatic cord--the cord that supplies blood to a testicle--becomes twisted, cutting off circulation to the affected testicle. Testicular torsion is characterized by sudden, severe pain and swelling in the scrotum.
MayoClinic.com states that testicular torsion is most common among males between the ages of 10 and 25, although the condition can occur at any age. A person with testicular torsion possesses an inherited trait that allows the testicles to rotate freely within the scrotum. Physical activity, scrotal injuries and sleep may contribute to the onset of testicular torsion. Along with sudden pain and swelling in one testicle, common signs and symptoms associated with testicular torsion include nausea and vomiting, lower abdominal pain and one testicle positioned higher than the other. Testicular torsion is a medical emergency that requires immediate surgical intervention.
