Skeletal Radiology

, Volume 47, Issue 6, pp 763–770 | Cite as

Gemelli-obturator complex in the deep gluteal space: an anatomic and dynamic study

  • Ramon BaliusEmail author
  • Antonio Susín
  • Carles Morros
  • Montse Pujol
  • Dolores Pérez-Cuenca
  • Xavier Sala-Blanch
Scientific Article



To investigate the behavior of the sciatic nerve during hip rotation at subgluteal space.

Materials and methods

Sonographic examination (high-resolution ultrasound machine at 5.0–14 MHZ) of the gemelli-obturator internus complex following two approaches: (1) a study on cadavers and (2) a study on healthy volunteers. The cadavers were examined in pronation, pelvis-fixed position by forcing internal and external rotations of the hip with the knee in 90° flexion. Healthy volunteers were examined during passive internal and external hip rotation (prone position; lumbar and pelvic regions fixed). Subjects with a history of major trauma, surgery or pathologies affecting the examined regions were excluded.


The analysis included eight hemipelvis from six fresh cadavers and 31 healthy volunteers. The anatomical study revealed the presence of connective tissue attaching the sciatic nerve to the structures of the gemellus-obturator system at deep subgluteal space. The amplitude of the nerve curvature during rotating position was significantly greater than during resting position. During passive internal rotation, the sciatic nerve of both cadavers and healthy volunteers transformed from a straight structure to a curved structure tethered at two points as the tendon of the obturator internus contracted downwards. Conversely, external hip rotation caused the nerve to relax.


Anatomically, the sciatic nerve is closely related to the gemelli-obturator internus complex. This relationship results in a reproducible dynamic behavior of the sciatic nerve during passive hip rotation, which may contribute to explain the pathological mechanisms of the obturator internal gemellus syndrome.


Deep gluteal syndrome Gemelli-obturator internus complex Sciatic nerve Obturator internal gemellus syndrome 



To Iñigo Iriarte (ARS Medica, Bilbao, Spain) for interpreting and doing the drawings and for Luis Vidal PhD for the management of the article.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© ISS 2017

Authors and Affiliations

  • Ramon Balius
    • 1
    • 2
    Email author
  • Antonio Susín
    • 3
  • Carles Morros
    • 4
  • Montse Pujol
    • 1
    • 5
  • Dolores Pérez-Cuenca
    • 4
  • Xavier Sala-Blanch
    • 6
    • 7
  1. 1.Consell Català de l’EsportGeneralitat de CatalunyaBarcelonaSpain
  2. 2.Sports Medicine DepartmentClínica DiagonalBarcelonaSpain
  3. 3.Math DepartmentUPC-BarcelonaTechBarcelonaSpain
  4. 4.Anesthesiology, Reanimation and Pain TherapyClínica DiagonalBarcelonaSpain
  5. 5.Facultad de FisioteràpiaUniversitat Internacional de CatalunyaSant Cugat del VallésSpain
  6. 6.Anatomy and Embryology Unit, Faculty of MedicineUniversitat of BarcelonaBarcelonaSpain
  7. 7.Department of AnesthesiologyHospital ClínicBarcelonaSpain

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