Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (1,044 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Five fused vertebrae forming a triangle-shaped structure at the back of the pelvis. It articulates superiorly with the lumbar vertebrae, inferiorly with the coccyx, and anteriorly with the ilium of the pelvis. The sacrum strengthens and stabilizes the pelvis.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Sacrums; Sacra; Sacral Vertebrae; Vertebrae, Sacral; Sacral Vertebra; Vertebra, Sacral.
Where it fits in the MeSH classification
- Broader topics
- Spine
Related concepts
- Vertebrae
- Pelvis
- Lumbar Vertebrae
- Coccyx
- Ilium
Research landscape
PubMed indexes 10,964 records tagged with the MeSH heading “Sacrum” (counts retrieved 2026-10-31). 1,911 of them (17.4%) were published from 2020 onward, and the busiest period so far is through 1999 with 3,522 records.
Reviews account for 965 records (8.8%) and meta-analyses for 49. Randomized controlled trials number 150 (1.4%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 3,522 |
| 2000-2009 | 2,214 |
| 2010-2019 | 3,317 |
| 2020 onward | 1,911 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 965 | 8.8% |
| Meta-analyses | 49 | 0.4% |
| Randomized controlled trials | 150 | 1.4% |
Method: PubMed query "Sacrum"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Accuracy of clinical neurological examination in diagnosing lumbo-sacral radiculopathy: a systematic literature review | 2017 | Systematic review Design not recorded in structured metadata | 60 | cc by PMID 28231784 · DOI · PMC5324296 |
| Global incidence of spinal perineural Tarlov's cysts and their morphological characteristics: a meta-analysis of 13,266 subjects | 2021 | Meta-analysis Design not recorded in structured metadata | 53 | cc by PMID 33452905 · DOI · PMC8164596 |
| Sacral neuromodulation in children and adolescents with chronic constipation refractory to conservative treatment | 2016 | Research article Design not recorded in structured metadata | 37 | cc by PMID 27294660 · DOI · PMC4947479 |
| Fixation of unstable sacral fractures by transpedicular system: a prospective study | 2026 | Research article Design not recorded in structured metadata | 0 | cc by PMID 41233652 · DOI · PMC12881057 |
Accuracy of clinical neurological examination in diagnosing lumbo-sacral radiculopathy: a systematic literature review [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundLumbar radiculopathy remains a clinical challenge among primary care clinicians in both assessment and diagnosis.
- Closing excerpt
- Whether these tests are able to detect the presence of disc herniation and subsequent nerve root compression or hyper-sensitivity of the sacral and femoral plexus due to mechanical irritation still remains debatable.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (359 words)
BackgroundLumbar radiculopathy remains a clinical challenge among primary care clinicians in both assessment and diagnosis. This often leads to misdiagnosis and inappropriate treatment of patients resulting in poor health outcomes, exacerbating this already debilitating condition. This review evaluated 12 primary diagnostic accuracy studies that specifically assessed the performance of various individual and grouped clinical neurological tests in detecting nerve root impingement, as established in the current literature.MethodsEight electronic data bases were searched for relevant articles from inception until July 2016. All primary diagnostic studies which investigated the accuracy of clinical neurological test (s) in diagnosing lumbar radiculopathy among patients with low back and referred leg symptoms were screened for inclusion. Qualifying studies were retrieved and independently assessed for methodological quality using the 'Quality Assessment of Diagnostic tests Accuracy Studies' criteria.ResultsA total of 12 studies which investigated standard components of clinical neurological examination of (sensory, motor, tendon reflex and neuro-dynamics) of the lumbo-sacral spine were included. The mean inter-observer agreement on quality assessment by two independent reviewers was fair (k = 0.3 - 0.7). The diagnostic performance of sensory testing using MR imaging as a reference standard demonstrated a sensitivity (confidence interval 95%) 0.61 (0.47-0.73) and a specificity of 0.63 (0.38-0.84). Motor tests sensitivity was poor to moderate, ranging from 0.13 (0.04-0.31) to 0.61 (0.36-0.83). Generally, the diagnostic performance of reflex testing was notably good with specificity ranging from (confidence interval 95%) 0.60 (0.51-0.69) to 0.93 (0.87-0.97) and sensitivity ranging from 0.14 (0.09-0.21) to 0.67 (0.21-0.94). Femoral nerve stretch test had a high sensitivity of (confidence interval 95%) 1.00 (0.40-1.00) and specificity of 0.83 (0.52-0.98) while SLR test recorded a mean sensitivity of 0.84 (0.72-0.92) and specificity of 0.78 (0.67-0.87).ConclusionsThere is a scarcity of studies on the diagnostic accuracy of clinical neurological examination testing. Furthermore there seem to be a disconnect among researchers regarding the diagnostic utility of lower limb neuro-dynamic tests which include the Straight Leg Raise and Femoral Nerve tests for sciatic and femoral nerve respectively. Whether these tests are able to detect the presence of disc herniation and subsequent nerve root compression or hyper-sensitivity of the sacral and femoral plexus due to mechanical irritation still remains debatable.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 28231784 · DOI · PMC5324296
Global incidence of spinal perineural Tarlov's cysts and their morphological characteristics: a meta-analysis of 13,266 subjects [2]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundSpinal perineural Tarlov's cysts (TCs) are considered incidental findings that occasionally might exert pressure upon nerve roots and correspond with patients' signs and symptoms.
- Closing excerpt
- The purported high incidence in PGAD requires confirmation in case-control studies for the risk-ratio calculation.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (281 words)
BackgroundSpinal perineural Tarlov's cysts (TCs) are considered incidental findings that occasionally might exert pressure upon nerve roots and correspond with patients' signs and symptoms. Purpose of this meta-analysis is to deliver global incidence and characteristics (location, size, and shape) of TCs.MethodsFollowing PRISMA checklist, all major databases were searched by two authors for radiologic studies reporting incidence and morphologic features (location, size, and shape) of TCs. Anatomical Quality Assessment tool was applied for risk of bias evaluation. Meta-analysis of random-effects model was employed. Subgroup analysis for regional distribution, gender, sacral levels, age, correspondence with symptoms, and persistent genital arousal disorder (PGAD) were planned ahead.Results22 radiologic studies of level 3 evidence involving 13,266 subjects were included. Global pooled prevalence of TCs was 4.18% (95% CI 2.47-6.30). Mean pooled sagittal diameter was 11.86 mm (95% CI 10.78-12.93). Sacral cysts strongly prevailed over the other segments. Of the sacral, S2 level was the most common (46.7% [95% CI 29.4-60.5]). Geographically, the highest incidence was found in Europe (6.07% [95% CI 1.49-13.00]), followed by North America (3.82% [95% CI 0.49-9.44]), and Asia (3.33% [95% CI 1.52-5.75]). TCs were more common in women than in men (5.84% vs 3.03%, p 2). Subjects with PGAD had incidence of 37.87% (95% CI 2.45-81.75). TCs in pediatric population are rare-0.53% (95% CI 0.02-1.51). 15.59% of TCs corresponded with symptoms.ConclusionsSpinal perineural (Tarlov) cysts are found in a minority of population. S2 level of the sacral bone is affected most frequently. There is female predominance. Correspondence with symptoms is seen in less than one-fifth of TCs. Studies with stronger evidence level are needed to corroborate the results. The purported high incidence in PGAD requires confirmation in case-control studies for the risk-ratio calculation.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 33452905 · DOI · PMC8164596
Sacral neuromodulation in children and adolescents with chronic constipation refractory to conservative treatment [3]
Abstract reading summary — source excerpts
- Opening excerpt
- PurposeFunctional constipation in children and adolescents is a common and invalidating condition.
- Closing excerpt
- 6) after 3 weeks of test treatment (p ConclusionSNM is a therapeutic option for children with chronic constipation not responding to intensive oral and/or laxative therapy, providing benefits that appear to be sustained over prolonged period of time.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (186 words)
PurposeFunctional constipation in children and adolescents is a common and invalidating condition. In a minority of patients, symptoms persist despite optimal conservative therapy. The aim of this study was to evaluate whether the short-term effects of sacral neuromodulation (SNM) in children and adolescents with constipation are sustained over prolonged period of time.MethodsPatients aged 10-20 years, with refractory constipation, fulfilling the Rome III criteria, were included in our study. If SNM test treatment showed >50 % improvement in defecation frequency, a permanent stimulator was implanted. Primary outcome measure was defecation frequency during 3 weeks. Secondary endpoints were abdominal pain and Wexner score. To assess sustainability of treatment effect, a survival analysis was performed. Cross-sectional quality of life was assessed using the EQ-5D VAS score.ResultsThirty girls, mean age 16 (range 10-20), were included. The mean defecation frequency increased from 5.9 (SD 6.5) in 21 days at baseline to 17.4 (SD 11.6) after 3 weeks of test treatment (p ConclusionSNM is a therapeutic option for children with chronic constipation not responding to intensive oral and/or laxative therapy, providing benefits that appear to be sustained over prolonged period of time.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 27294660 · DOI · PMC4947479
Fixation of unstable sacral fractures by transpedicular system: a prospective study [4]
Abstract reading summary — source excerpts
- Opening excerpt
- PurposeThis study aimed to assess the functional and radiological outcome of transpedicular fixation system for managing unstable sacral fractures in adults.
- Closing excerpt
- Trial registration(ID/NCT06888583) retrospectively registered.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (218 words)
PurposeThis study aimed to assess the functional and radiological outcome of transpedicular fixation system for managing unstable sacral fractures in adults.MethodsThis prospective case series study included 21 patients with unstable type C sacral fractures according to AO Spine classification of sacral fractures. The patients were treated by a transpedicular fixation system connecting the lower lumbar spine to the ilium, as a vertical element, which was bilateral in seven cases and unilateral in 14 cases. A transverse element connecting both sides of the posterior pelvic ring was added to augment fixation in the transverse plane. The minimum period of follow-up was 12 months.ResultsMean Majeed Score was 84,29 ± 9.97; excellent, good and fair classes were present in 14 (66.7%), five (23.8%) and two (9.5%) patients, respectively. There was a significant reduction of the vertical, anterior posterior and rotational displacement postoperatively in comparison to preoperative measures. There was a significant improvement in neurological deficit postoperatively. Eight (38.1%) patients developed complications postoperatively. Wound Infection was the most common complication.ConclusionThe use of transpedicular fixation as a vertical element combined with a transverse element connecting both sides of the posterior pelvic ring, to treat unstable sacral fractures, offers adequate fixation strength that helps to achieve union in a well reduced position, leads to satisfactory functional outcome and improves neurological deficit.Trial registration(ID/NCT06888583) retrospectively registered.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41233652 · DOI · PMC12881057
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Congenital lumbosacral lipomas [5]
- Research article Sacropelvic fixation: techniques and complications [6]
- Research article Incidence and risk factors for proximal junctional kyphosis: a meta-analysis [7]
- Research article Robot-assisted sacrocolpopexy for pelvic organ prolapse: a systematic review and meta-analysis of comparative studies [8]
- Research article The controversy surrounding sacral insufficiency fractures: to ambulate or not to ambulate? [9]
- Research article Fragility fractures of the sacrum: how to identify and when to treat surgically? [10]
References
- Tawa N, Rhoda A, Diener I. Accuracy of clinical neurological examination in diagnosing lumbo-sacral radiculopathy: a systematic literature review. . 2017. PMID 28231784 · DOI · PMC5324296
- Klepinowski T, Orbik W, Sagan L. Global incidence of spinal perineural Tarlov's cysts and their morphological characteristics: a meta-analysis of 13,266 subjects. . 2021. PMID 33452905 · DOI · PMC8164596
- van der Wilt AA, van Wunnik BP, Sturkenboom R, Han-Geurts IJ, Melenhorst J, Benninga MA, et al.. Sacral neuromodulation in children and adolescents with chronic constipation refractory to conservative treatment. . 2016. PMID 27294660 · DOI · PMC4947479
- Elmoghany ME, Gharbo NO, Ayoub MA, Farouk OA, Mashal HEY. Fixation of unstable sacral fractures by transpedicular system: a prospective study. . 2026. PMID 41233652 · DOI · PMC12881057
- Pierre-Kahn A, Zerah M, Renier D, Cinalli G, Sainte-Rose C, Lellouch-Tubiana A, et al.. Congenital lumbosacral lipomas. Childs Nerv Syst. 1997. PMID 9272285 · DOI
- Kebaish KM. Sacropelvic fixation: techniques and complications. Spine (Phila Pa 1976). 2010. PMID 21102300 · DOI
- Liu FY, Wang T, Yang SD, Wang H, Yang DL, Ding WY. Incidence and risk factors for proximal junctional kyphosis: a meta-analysis. Eur Spine J. 2016. PMID 26994925 · DOI
- Serati M, Bogani G, Sorice P, Braga A, Torella M, Salvatore S, et al.. Robot-assisted sacrocolpopexy for pelvic organ prolapse: a systematic review and meta-analysis of comparative studies. Eur Urol. 2014. PMID 24631406 · DOI
- Babayev M, Lachmann E, Nagler W. The controversy surrounding sacral insufficiency fractures: to ambulate or not to ambulate?. Am J Phys Med Rehabil. 2000. PMID 10892628 · DOI
- Wagner D, Ossendorf C, Gruszka D, Hofmann A, Rommens PM. Fragility fractures of the sacrum: how to identify and when to treat surgically?. Eur J Trauma Emerg Surg. 2015. PMID 26038048 · DOI · PMC4523697
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.