Simultaneous pain in your stomach and buttocks usually traces to shared nerve pathways, overlapping anatomy, or a single condition that affects both your gut and your pelvic floor. Your abdomen and rectum sit close together, and the nerves serving them often converge in the spinal cord, which means irritation in one area can register as pain in the other. The range of possible causes is wide, from everyday constipation and irritable bowel syndrome to conditions that genuinely need medical attention, so understanding the pattern matters more than the pain itself.
Why These Two Areas Are Connected
Your abdominal organs and the muscles and nerves around your rectum and buttocks are not as separate as they feel from the outside. The lower intestines, rectum, and pelvic floor muscles all receive nerve signals that travel along overlapping routes before entering the spinal cord. When one structure becomes inflamed or irritated, the brain can misread where the signal is coming from and project pain to a neighboring region. This is the same general principle behind why a heart attack sometimes causes jaw pain: the wiring is shared, and the brain’s map is imprecise.
The pelvis is essentially a bowl that holds your lower intestines, bladder, reproductive organs, and rectum. Anything that swells, spasms, or becomes inflamed inside that bowl can press on nearby structures. A cramping colon can irritate the muscles of the pelvic floor; a spasming anal sphincter can trigger reflex tension in the lower abdomen. This anatomical proximity is the single biggest reason these two complaints show up together so often.
Irritable Bowel Syndrome and Rectal Sensitivity
IBS is one of the most common reasons people experience both abdominal cramping and rectal discomfort at the same time. The condition involves disordered gut motility and heightened sensitivity of the intestinal lining, and that sensitivity extends all the way down to the rectum. Research measuring how much rectal distension triggers pain found that about two-thirds of IBS patients had rectal hypersensitivity, meaning their rectum registered pain at lower-than-normal thresholds.1PubMed Central. Relationship between rectal sensitivity, symptoms intensity and quality of life in patients with irritable bowel syndrome In practical terms, a volume of stool or gas that would feel unremarkable to someone else can feel genuinely painful if you have IBS.
People with IBS often describe the dual pain as cramping in the lower belly that coincides with a pressure or aching sensation in the rectum and sometimes deeper into the buttocks. The cramping usually eases somewhat after a bowel movement, though rectal soreness can linger. Stress and certain foods can ramp up the sensitivity, and many people notice the combination is worse during high-anxiety periods or after eating triggering meals.
Proctalgia Fugax
If the rectal part of your pain comes on suddenly, feels sharp or cramping, and disappears within minutes, you may be experiencing proctalgia fugax. This is a functional pain syndrome caused by spontaneous spasms of the anal sphincter muscles. The episodes can be intense enough to make you break out in a sweat, but they generally resolve on their own.2PubMed Central. Proctalgia fugax Because the pelvic floor muscles connect to the lower abdominal wall through shared fascia and nerve pathways, people having a proctalgia fugax episode sometimes also report a dull ache or cramping in the lower abdomen.
Proctalgia fugax is surprisingly common and is considered benign, though the pain itself can be alarming. It tends to strike at night and is more frequent in people who also deal with anxiety or IBS. If your episodes are brief, infrequent, and self-limiting, this is likely the explanation. If they last longer than about 20 minutes or happen repeatedly, a doctor can help distinguish this from other causes of anorectal pain.
Crohn’s Disease and the Perianal Connection
Inflammatory bowel disease, particularly Crohn’s disease, is one of the more serious reasons stomach and buttock pain overlap. Crohn’s can inflame any part of the digestive tract, and it has a well-documented tendency to also affect the tissue around the anus and rectum. Perianal Crohn’s disease produces abscesses, fistulas (abnormal tunnels between the bowel and the skin near the buttocks), skin tags, fissures, and strictures.3PubMed Central. Perianal Crohn’s Disease These complications cause deep, throbbing pain in and around the buttocks that exists alongside the abdominal cramping, diarrhea, and weight loss that Crohn’s produces higher up in the gut.
A key red flag here is when someone presents with a perianal fistula and also has unexplained abdominal pain, weight loss, or chronic diarrhea. A systematic review developing a diagnostic index for this scenario found that abdominal pain and weight loss were strongly associated with undiagnosed Crohn’s in patients who initially showed up with perianal problems.4PubMed Central. Early diagnosis of Crohn’s disease in patients presenting with a perianal fistula: systematic review and development of a perianal red flags index If you have recurring perianal abscesses or fistulas along with belly pain and unintended weight loss, it is worth asking a gastroenterologist about Crohn’s specifically.
Endometriosis Affecting the Bowel
For people with a uterus, endometriosis is an underappreciated cause of simultaneous abdominal and rectal or buttock pain. Endometrial tissue can grow on or into the wall of the bowel, particularly the rectum and sigmoid colon. Bowel endometriosis often produces changes in bowel habits like constipation or diarrhea, painful bowel movements, painful periods, and pain during sex.5PubMed Central. Bowel Endometriosis: Current Perspectives on Diagnosis and Treatment The pain from bowel endometriosis can radiate into the buttocks and lower back because the implants irritate the nerves that run through the pelvis.
What makes bowel endometriosis tricky is that the symptoms overlap heavily with IBS, and many people are initially given an IBS diagnosis before anyone considers endometriosis. A distinguishing clue is cyclical worsening: if your stomach and buttock pain predictably gets worse around your period, that pattern points toward endometriosis rather than a purely functional gut problem. Some people with bowel endometriosis have no symptoms at all, which means the condition can be present for years before it causes noticeable problems.
Pelvic Infections
Infections in the pelvis can produce pain that radiates in both directions, hitting the lower abdomen and the rectum or buttocks simultaneously. Pelvic inflammatory disease, an infection of the reproductive organs usually caused by sexually transmitted bacteria, is a classic example. A case report described a patient who presented with severe, spasmodic rectal pain alongside lower abdominal discomfort, vaginal discharge, and cervical tenderness. Imaging revealed ovarian inflammation pressing against pelvic structures, and the rectal spasms resolved once the infection was treated with antibiotics.6PubMed Central. Pelvic Inflammatory Disease With Presumptive Tubo-Ovarian Abscess Presenting With Rectal Spasm
Infectious proctitis is another possibility, particularly in people who have had receptive anal contact. Bacteria and viruses including gonorrhea, chlamydia, herpes simplex, and syphilis can infect the rectal lining and cause pain, discharge, and bleeding localized to the rectum that is often accompanied by crampy lower abdominal pain from the resulting inflammation spreading upward.7PubMed Central. Infectious proctitis: what every gastroenterologist needs to know These infections are treatable, but they need the right antibiotic or antiviral, so getting tested matters.
Sacroiliac Joint Problems and Referred Pain
Not every case of combined stomach-and-buttock pain originates in the gut. The sacroiliac joints, where your spine meets your pelvis, can refer pain to both the lower abdomen and the buttocks when they are inflamed or misaligned. Case reports have documented patients with chronic lower back pain and unexplained lower abdominal pain that turned out to be sacroiliac joint dysfunction. In those cases, injecting the sacroiliac joint with anesthetic and corticosteroid relieved both the back pain and the abdominal pain.8PubMed. Unexplained lower abdominal pain associated with sacroiliac joint dysfunction: report of 2 cases
This is an easy diagnosis to miss because most people, and many clinicians, do not associate lower belly pain with a joint problem in the back. If your abdominal and buttock pain worsens with certain body positions, after prolonged sitting, or when climbing stairs, and imaging of your gut has come back clean, the sacroiliac joint is worth investigating. Physical therapists and physiatrists are often the ones who catch this after gastroenterologists have ruled out everything else.
Pudendal Nerve Irritation
The pudendal nerve runs through a narrow canal near the base of your pelvis and supplies sensation to the perineum, rectum, and surrounding structures. When this nerve gets compressed or irritated, the pain can show up in the buttocks, rectum, and lower abdomen all at once. A case report described a patient who developed burning and tingling pain in the buttock and ischial areas that radiated into the genital region and thighs, linked to inflammation of the tissues near the nerve’s anatomical pathway around the ischial tuberosity.9Reumatismo. Pudendal nevralgia as an unusual presenting symptom of axial spondyloarthritis
Pudendal neuralgia typically worsens with sitting and improves when standing or lying down, which is a useful distinguishing feature. People describe it as burning, stabbing, or a “pins and needles” feeling deep in the pelvis. It can result from prolonged cycling, pelvic surgery, childbirth, or inflammatory conditions that cause swelling around the nerve’s path. Because the pain distribution is so spread out, pudendal neuralgia often gets mistaken for a gut problem or a urinary issue before anyone thinks to evaluate the nerve itself.
Opioid and Medication Side Effects
If you are taking opioid pain medication for any reason, the drugs themselves can cause both abdominal and rectal pain. Opioids slow gut motility throughout the digestive tract, leading to constipation, bloating, abdominal cramping, and spasms. They also disrupt anorectal function, causing sphincter dysfunction that leads to straining, hemorrhoids, and a sensation of incomplete evacuation. Research on opioid-induced bowel dysfunction found that roughly a third of patients on opioid analgesics reported a feeling of anal blockage.10PubMed Central. Opioid-Induced Constipation and Bowel Dysfunction: A Clinical Guideline
The resulting fecal impaction, where hardened stool accumulates in the rectum, can press on pelvic nerves and cause deep aching in both the lower abdomen and the buttocks. This is not limited to prescription opioids; over-the-counter medications containing codeine and even chronic overuse of loperamide (the active ingredient in many anti-diarrheal products) can produce similar effects. If your dual pain started or worsened after beginning a new medication, that timing is worth mentioning to your doctor.
Pelvic Congestion Syndrome
Pelvic congestion syndrome is caused by dilated veins in the pelvis, somewhat like varicose veins in the legs but located internally. It produces a dull, heavy aching in the lower abdomen that can radiate into the buttocks, thighs, and lower back. A large study of over 2,300 women found that dilated pelvic veins appeared in about 12% of those scanned, and among premenopausal women the rate was higher, around 21%. Chronic pelvic pain of unclear cause had been documented in about 18% of women with the dilated veins.11PubMed Central. A forgotten disease: Pelvic congestion syndrome as a cause of chronic lower abdominal pain
The pain from pelvic congestion syndrome tends to worsen after standing for long periods, after sex, and around menstruation. It is sometimes accompanied by urinary symptoms like frequent urination or discomfort while urinating, even when no infection is present. Because the symptoms are vague and overlap with so many other conditions, pelvic congestion syndrome has earned the label of a “forgotten disease.” Diagnosis usually requires imaging that specifically looks for dilated veins, which standard ultrasounds and CT scans may miss unless the radiologist is looking for them.
The Pelvic Appendix
The appendix does not always sit where the textbooks put it. In a substantial number of people, the appendix hangs down into the pelvis rather than pointing upward or sideways. When a pelvic-positioned appendix becomes inflamed, it can irritate the rectum and bladder directly, producing rectal pain and urgency alongside the expected abdominal symptoms. A study examining the diagnostic accuracy of rectal examination for appendicitis found that the pelvic appendix was the most common anatomical variant encountered during surgery.12Journal of Life Science and Public Health. Diagnostic Accuracy of Per-Rectal Examination in Acute Appendicitis: Correlation with Anatomical Appendix Type
This matters because pelvic appendicitis can present differently from the classic textbook description. Instead of sharp pain in the lower right abdomen, you might feel vague lower belly discomfort with prominent rectal or buttock pain, leading both patients and doctors to look in the wrong direction initially. If you develop worsening abdominal pain with rectal discomfort, fever, and loss of appetite over a day or two, appendicitis should be on the list even if the pain does not match the stereotype.
How Doctors Sort It Out
When someone presents with pain in both the abdomen and the anorectal or buttock area, doctors generally start by ruling out structural problems that need urgent attention. A clinical review on anorectal and pelvic pain outlined the typical workup: anoscopy to check for fissures and hemorrhoids, flexible sigmoidoscopy to look for inflammation of the rectal lining (which can point to inflammatory bowel disease), and pelvic MRI if an abscess or fistula is suspected.13PubMed Central. Anorectal and Pelvic Pain Blood work, stool tests, and sometimes CT imaging help narrow things further.
The diagnostic process often depends on what additional symptoms you bring to the table. Bloody stools and weight loss push toward IBD. Cyclical worsening around periods points toward endometriosis. Pain that worsens with sitting and eases when standing suggests pudendal nerve involvement. Fever and discharge suggest infection. Giving your doctor a clear description of the pain pattern, timing, and associated symptoms is genuinely one of the most useful things you can do to speed up the process.
When to Seek Urgent Care
Most causes of simultaneous stomach and buttock pain are not emergencies, but a few demand prompt attention. Seek medical care quickly if you have severe, escalating abdominal pain with fever, which can signal appendicitis, a pelvic abscess, or another acute infection. Uncontrolled rectal bleeding or bloody diarrhea with abdominal pain warrants same-day evaluation. Sudden inability to pass stool or gas combined with distension and vomiting suggests a bowel obstruction. And any new combination of pelvic pain with unexplained weight loss, night sweats, or a change in bowel habits lasting more than a few weeks deserves investigation even if it does not feel like an emergency, because these patterns sometimes point to inflammatory or malignant conditions that benefit from early detection.