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The anatomy and function of the obturator externus
Ravindra Gudena1, Abdullah Alzahrani1, Pamela Railton1
1Orthopaedic Trauma and Lower Extremity Reconstruction, University of Calgary, Calgary, Alberta - Canada.
Summary
The Obturator Externus muscle aids in hip joint stability. This study reveals its role in external rotation and adduction, clarifying its functional anatomy.
Area of Science:
- Anatomy
- Biomechanics
- Orthopedics
Background:
- Limited understanding of the Obturator Externus (OE) muscle's anatomy and function.
- Existing descriptions focus on its origin, tendon path, and insertion.
- Need for detailed investigation into its relationship with the acetabulum and its actions.
Purpose of the Study:
- To describe the morphology of the Obturator Externus muscle.
- To elucidate its anatomic relationship to the acetabulum.
- To postulate the functional actions of the Obturator Externus muscle.
Main Methods:
- Dissection of eighteen fresh human cadaveric hips.
- Utilized a plastic pelvis and femur model.
- Employed a string model technique (based on Beck et al.) to simulate muscle action.
Main Results:
- Detailed description of Obturator Externus muscle morphology.
- Demonstrated its stabilizing role for the femoral head within the acetabulum.
- Mechanical modeling indicated primary action as external rotation (neutral and 90° flexion) and secondary action as adduction (hip flexion).
Conclusions:
- The Obturator Externus muscle is crucial for hip joint stability.
- Its primary function is external rotation of the femur.
- It also contributes to adduction, particularly during hip flexion.
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