Piriformis fossa - an anatomical and orthopedics consideration.
BACKGROUND
Piriformis fossa is an important anatomical landmark having significant clinical value in orthopedic surgery; but its location and anatomical relationship with surrounding structures are not clearly defined. Hence it is necessary to clearly describe it in respect to anatomical and orthopedic aspect.


METHODS
Fifty Cadaveric dry femoral bones and Dissection of the four hip specimens were used to study the Piriformis fossa in respect to location and its relationship with surrounding structures. Clinical importance of piriformis fossa was determined in reference to antegrade femoral nail insertion.


METHODS
Piriformis muscle and so called piriformis fossa are unrelated entities. Piriformis fossa is anatomical site of insertion of obturator externus. In dry cadaveric femora; fossa was not always located in the direction of femoral shaft. It was located in the direction of femoral shaft in 24% cases only. In 68% cases femoral canal was aligned lateral and in 8% cases, it lies medial to the fossa.


CONCLUSIONS
Piriformis fossa should be named as Trorchanteric fossa or Obturator fossa for better anatomical description. So called Piriformis fossa does not found to be universally corresponding to femoral shaft hence selection of entry site should be based on variable proximal femur and area on femur which corresponds to femoral shaft.
Associate Professor, Department of Orthopedics, ESI - Postgraduate Institute of Medical Sciences and Research , New Delhi, India .
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Lakhwani
Assistant Professor, Department of Anatomy, Sri Aurobindo Medical College and Postgraduate Institute , Indore (M.P.), India .
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Mittal
Professor and Head, Department of Anatomy, S. S. Medical College , Rewa (M.P.), India .
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Naik
Femoral nail; Piriformis fossa; Piriformis muscle; Trochanteric fossa