To evaluate the safe triangle within the femoral triangle for the potential space of the true anterior hip approach.

Cadaveric dissections were carried out on 28 femoral triangles from 14 cadavers. This study measured the length of the direct head of the rectus femoris from the anterior inferior iliac spine (AIIS) to the patella upper pole, the AIIS to the lateral border of the femoral nerve, and the entry point of the femoral nerve and vessel branches to the rectus. The safe portion within the risky femoral triangle was analyzed and applied to two clinical situations, a femoral head fracture and septic hip arthritis.

The examination showed that there were three terminal branches to the rectus femoris from the femoral nerve. The entry point of the first branch was at the proximal 20.0-28.9% portion of the rectus femoris. The second and the third branch entered at the proximal 22.5-37.5% and 24.9-41.0%, portion, respectively. The vessel entry was at 21.4-37.3%. The length from the AIIS to the femoral nerve was 3.5-8.0 cm. Using this space, the procedure was easier to perform in the two situations mentioned above.

The space within the femoral triangle between the proximal 20% of the rectus femoris and iliacus can be used as one of the potential spaces for femoral head fracture fixation and septic hip irrigation in children, and as an arthroscopy portal.