Retroperitoneal part of the femoral nerve. Normal ultrasound features.

The retroperitoneal part of the normal femoral nerve has been studied in 34 healthy subjects with ultrasound (US) to evaluate its course, thickness and anteroposterior diameter. A correlative cadaver study was also undertaken; a cadaver was scanned during dissection, and 12 cadavers were studied macroscopically to evaluate the length of the retroperitoneal part of the nerve. Because the femoral nerve could be well seen in its course in the retroperitoneum with US, it is suggested in this study which--to the authors' knowledge--is the first report on imaging of the femoral nerve, that sonography may serve as an initial imaging tool to detect lesions of the nerve itself as well as lesions adjacent to it.