Educational only — not medical advice. This page explains a published mechanism of a medical condition for general education. It is not a diagnosis, not a treatment plan, and not a substitute for evaluation by a qualified clinician.
ACNES: Why One Spot on Your Belly Hurts When Every Scan Is Normal
A 107-second narrated 3D animation of anterior cutaneous nerve entrapment syndrome (ACNES), a trapped nerve in the belly wall that is often missed after a normal GI workup. It shows the sharp turn where the nerve gets caught, Carnett's test and how the condition is treated, with the full transcript and the references behind its claims.
Transcript
What the video says, beat by beat
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Stomach pain in one spot, normal scans
“Stomach pain in one spot, and every scan comes back normal? The cause may be a trapped nerve in the belly wall, not in your gut.”[1,3,4]
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A sharp turn through a tight ring
“Nerves from your lower ribs wrap around to the front of your belly. At the edge of the long stomach muscle, each one turns sharply and passes through a tight ring of tissue on its way to the skin.”[1,2]
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A nerve caught at the ring
“That ring is where a nerve can get caught, sometimes after surgery or near a laparoscopy scar, and often with no clear trigger at all. The pain is sharp or burning, in a spot you can cover with a fingertip.”[1,15]
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Carnett's test
“A thirty-second test helps sort it out. Lying flat, you press on the spot, then lift your head to tighten your stomach muscles. If the pain stays the same or gets worse, the belly wall is the likely source. If it eases, the cause is more likely inside.”[3,5]
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The injection is the test
“A numbing injection at the spot confirms it. If the pain drops by at least half within twenty minutes, it points to that nerve. Repeat injections alone give lasting relief to about one in five people.”[3,6,7]
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Removing the trapped ending
“When the test confirms the nerve and the pain keeps coming back, a small operation removes the trapped nerve endings. It has the best long-term results of any treatment studied, and about six in ten people stay pain-free for years.”[9,10,11,12,13]
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Signs the problem is inside the abdomen
“Pain that comes on suddenly and severely, vomiting blood, black or bloody stools, or a belly that turns hard and rigid point to a problem inside the abdomen. Those need the nearest emergency room, or call 911.”[14]
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Find the exact spot
“Pain you can cover with a fingertip deserves a closer look.”[3]
What the science says
References
According to PubMed: every journal reference below was verified against its live PubMed record on October 6, 7 or 10, 2026, and the MedlinePlus page against its current version (reviewed January 13, 2026). Numeric findings from individual studies are attributed to those studies and are not promises of results. BodyParts3D models the intercostal nerve trunks but not their front skin branches, so the branch and the fibrous ring in the film are drawn from the anatomy described in references 1 and 2. The film shows the T10 nerve as an example. ACNES can involve any of the lower intercostal nerves, from T7 to T12.
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Scheltinga MR, Roumen RM. Anterior cutaneous nerve entrapment syndrome (ACNES). Hernia. 2018;22(3):507-516.
Covers: a review of ACNES — the terminal branches of the lower intercostal nerves that reach the front of the abdominal wall, why the abdominal wall is so often overlooked as a source of chronic abdominal pain, the history and examination, and treatment from injections to removal of the terminal nerve branches
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Applegate WV. Abdominal cutaneous nerve entrapment syndrome. Surgery. 1972;71(1):118-124.
Covers: the original description of the syndrome — the anterior cutaneous branch turning sharply to pass through the rectus abdominis toward the skin, where it can be trapped. The film's ring is drawn from this description (no abstract is indexed)
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Shian B, Larson ST. Abdominal Wall Pain: Clinical Evaluation, Differential Diagnosis, and Treatment. Am Fam Physician. 2018;98(7):429-436.
Covers: ACNES as the most common and most often missed cause of abdominal wall pain, typically at the lateral edge of the rectus abdominis. A positive Carnett's test (tenderness that stays the same or worsens when the abdominal muscles are tensed). A local anesthetic injection can confirm the diagnosis when pain improves by 50% afterward
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Koop H, Koprdova S, Schürmann C. Chronic Abdominal Wall Pain. Dtsch Arztebl Int. 2016;113(4):51-57.
Covers: abdominal wall pain is 2-3% of chronic abdominal pain overall and up to 30% when no other cause is found. Reported long-term relief was 20-30% after a single lidocaine injection and 40-50% after repeated injections, from a small number of clinical studies
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Otero Regino W, Jaramillo Trujillo G, Otero Parra L, et al. Comparison of two maneuvers to identify Carnett's sign in patients with chronic abdominal pain. Randomized controlled clinical trial. Rev Gastroenterol Peru. 2025;45(1):8-15. [Article in Spanish]
Covers: lifting the head and shoulders and lifting both legs identified Carnett's sign similarly well (a randomized trial of 1,320 patients)
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Boelens OB, Scheltinga MR, Houterman S, Roumen RM. Randomized clinical trial of trigger point infiltration with lidocaine to diagnose anterior cutaneous nerve entrapment syndrome. Br J Surg. 2013;100(2):217-221.
Covers: a double-blind trial of 48 patients — 10 ml of 1% lidocaine just beneath the anterior rectus fascia at the point of maximal pain gave a successful response (pain at least halved, or down two points on a five-point verbal scale) 15-20 minutes after injection in 13 of 24, against 4 of 24 after saline
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Mol FMU, Heukelsfeldt Jansen C, Boelens OB, et al. Adding steroids to lidocaine in a therapeutic injection regimen for patients with abdominal pain due to anterior cutaneous nerve entrapment syndrome (ACNES): a single blinded randomized clinical trial. Scand J Pain. 2018;18(3):505-512.
Covers: 136 patients given three injections two weeks apart — adding methylprednisolone did not raise the success rate (lidocaine alone 38% vs lidocaine plus steroid 31% at 6 weeks, 20% vs 18% at 12 weeks). Lidocaine alone gave long-term relief in about 1 in 5
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Boelens OB, Scheltinga MR, Houterman S, Roumen RM. Management of anterior cutaneous nerve entrapment syndrome in a cohort of 139 patients. Ann Surg. 2011;254(6):1054-1058.
Covers: 139 patients (77% women, mean age 47) — 81% of those injected (94 patients) had at least 50% relief after the first lidocaine injection, 33% stayed pain-free after a course of injections that included a corticosteroid, and neurectomy helped 49 of 69 (71%) who needed it
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Boelens OB, van Assen T, Houterman S, Scheltinga MR, Roumen RM. A double-blind, randomized, controlled trial on surgery for chronic abdominal pain due to anterior cutaneous nerve entrapment syndrome. Ann Surg. 2013;257(5):845-849.
Covers: neurectomy against sham surgery, with patients and the lead investigator blinded — at six weeks, 16 of 22 patients had a successful response after neurectomy, against 4 of 22 after the sham operation
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van Assen T, Boelens OB, van Eerten PV, et al. Long-term success rates after an anterior neurectomy in patients with an abdominal cutaneous nerve entrapment syndrome. Surgery. 2015;157(1):137-143.
Covers: success held in 61% at an average of 32 months after anterior neurectomy
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Ten Have T, van Geffen ST, Zwaans WAR, et al. Pulsed radiofrequency or surgery for anterior cutaneous nerve entrapment syndrome: Long-term results of a randomized controlled trial. Pain Pract. 2024;24(2):288-295.
Covers: long-term follow-up of the randomized trial in reference 13 — at a median of almost six years (71.5 months), 13 of 21 (62%) in the neurectomy group were pain-free with no further treatment, against one patient in 23 after a single pulsed radiofrequency session (five more were pain-free after repeated sessions)
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De Troyer A, Allaeys M, Verelst F, Berrevoet F. Management strategies for anterior cutaneous nerve entrapment syndrome: a scoping review. Hernia. 2026;30(1):72.
Covers: 18 studies and 3,007 patients — neurectomy gave long-term relief in 61% and the best long-term effect of any treatment. Pulsed radiofrequency succeeded in about 20%, with a median effect of four months
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Maatman RC, van Kuijk SMJ, Steegers MAH, et al. A Randomized Controlled Trial to Evaluate the Effect of Pulsed Radiofrequency as a Treatment for Anterior Cutaneous Nerve Entrapment Syndrome in Comparison to Anterior Neurectomy. Pain Pract. 2019;19(7):751-761.
Covers: the one randomized trial comparing the two (66 patients, not blinded) — pain fell further after neurectomy at eight weeks, and 17 of 28 (61%) met the success threshold against 12 of 32 (38%) after pulsed radiofrequency, a difference that did not reach statistical significance
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MedlinePlus (U.S. National Library of Medicine). Abdominal pain — When to contact a medical professional.
Covers: get immediate help for sudden, sharp abdominal pain. Vomiting blood or blood in the stool (bright red, maroon, or black and tarry). A belly that is rigid and hard to the touch. Trouble breathing
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Smelt H, Pouwels S, Apers JA, Said M, Smulders J. Anterior Cutaneous Nerve Entrapment Syndrome: Two Case Reports of the Forgotten Diagnosis After Bariatric Surgery. Cureus. 2020;12(6):e8499.
Covers: two patients with ACNES after laparoscopic bariatric surgery, each diagnosed only after a long delay and many imaging studies, both briefly pain-free after a lidocaine test injection and pain-free after neurectomy (case reports)