Right Lower Quadrant Pain: Location and Common Causes
Anatomical Location
The right lower quadrant (RLQ) is the area of the abdomen located below the umbilicus (belly button) and to the right of the midline. This region extends from the midline to the right flank and from the umbilicus down to the groin 1.
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Clinical Significance and Common Causes
RLQ pain accounts for nearly 50% of patients presenting to emergency departments with abdominal pain, with appendicitis being the most common surgical cause. 1
Most Common Etiologies:
Appendicitis is the most frequent surgical pathology responsible for RLQ pain in the United States and the most common cause requiring emergent surgery 1
Right-sided colonic diverticulitis represents a less frequent but important cause of RLQ pain 1, 2
Ureteral stones can present with RLQ pain when affecting the right ureter 1
Colitis (inflammatory or infectious) affecting the right colon or terminal ileum 1, 2
Intestinal obstruction, particularly when involving the terminal ileum or cecum 1
Additional Differential Diagnoses:
Gynecologic pathology in women of reproductive age, including ovarian torsion, ectopic pregnancy, pelvic inflammatory disease, and adnexal masses 1
Mesenteric adenitis, particularly in younger patients 2
Meckel diverticulum 2
Inflammatory bowel disease (Crohn's disease affecting the terminal ileum) 1, 2
Right colon cancer, especially in elderly patients 1
Psoas abscess or retroperitoneal pathology, particularly when accompanied by hip flexion weakness 4
Key Clinical Pearls:
In pregnant patients, pain location may not reliably correlate with appendicitis, as the appendix is displaced superiorly by the gravid uterus 1
Clinical examination alone has historically poor diagnostic accuracy for appendicitis, with negative appendectomy rates as high as 25% without imaging 1
Rebound tenderness in the RLQ has the highest positive predictive value (65%) for complicated appendicitis 5