Citation, DOI, disclosures and article data
Citation:
Feger J, Knipe H, Ischial spine sign. Reference article, Radiopaedia.org (Accessed on 13 Mar 2025) https://doi.org/10.53347/rID-79760
Disclosures:
At the time the article was last revised Henry Knipe had the following disclosures:
- Micro-X Ltd, Shareholder (past)
These were assessed during peer review and were determined to
not be relevant to the changes that were made.
View Henry Knipe's current disclosures
The ischial spine sign is a radiographic sign on the AP view of the pelvis for the diagnosis of acetabular retroversion, which poses a form of pincer morphology and predisposes to femoroacetabular impingement.
Acetabular retroversion seems to result from a rotation of the entire acetabular complex, including the ischial spine 1.
Radiographic features
The triangular projection of the ischial spine is visible medially to the pelvic inlet or iliopectineal line. The sign is supposed to have a sensitivity and specificity of 90% and 71% 2 even with suboptimal pelvic tilt and or pelvic rotation and specificity of >90% with neutral orientation 1,2.
Limitations
Visibility of the ischial spine increases with pelvic tilt and ipsilateral pelvic rotation.
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1. Kalberer F, Sierra R, Madan S, Ganz R, Leunig M. Ischial Spine Projection into the Pelvis : A New Sign for Acetabular Retroversion. Clin Orthop Relat Res. 2008;466(3):677-83. doi:10.1007/s11999-007-0058-6 - Pubmed
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2. Kakaty D, Fischer A, Hosalkar H, Siebenrock K, Tannast M. The Ischial Spine Sign: Does Pelvic Tilt and Rotation Matter? Clin Orthop Relat Res. 2010;468(3):769-74. doi:10.1007/s11999-009-1021-5 - Pubmed
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3. Werner C, Copeland C, Ruckstuhl T et al. Radiographic Markers of Acetabular Retroversion: Correlation of the Cross-Over Sign, Ischial Spine Sign and Posterior Wall Sign. Acta Orthop Belg. 2010;76(2):166-73. - Pubmed
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4. Qoreishy M, S Hosseinzadeh H, Keipourfard A, Shoghli A. Diagnostic Value of Ischial Spine Sign in Patients with Acetabular Retroversion. Arch Bone Jt Surg. 2019;7(2):168-72. PMC6510926 - Pubmed
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