Anatomic motor point localization for partial quadriceps block in spasticity

Objective: To identify the location of the vastus intermedius nerve and its motor point (point M) and to precisely identify its coordinates in relation to anatomic surface landmarks. Design: Descriptive study. Setting: Anatomy institute of a university school of medicine. Participants: Twenty-nine adult cadaver Limbs immobilized in anatomic position. Intervention: Anatomic dissection to identify point M, Anatomic surface landmarks were point F, the issuing point of femoral nerve under the inguinal ligament; point R, the middle of superior edge of the patella; segment FR, which corresponds to thigh length; point M', point M orthogonal projection on segment FR, Mean Outcome Measure: Absolute vertical coordinate, distance FM, relative vertical coordinate compared to the thigh length, FM'/FR ratio; absolute horizontal coordinate, distance MM', Results: The absolute vertical coordinate was 11.7 +/- 2cm. The relative vertical coordinate was at .29 +/- .04 of thigh length. The horizontal coordinate was at 2 +/- .5cm lateral to the FR line. Conclusion: Point M can be defined with relative precision by two coordinates. Application and clinical interest of nerve blocking using these coordinates in quadriceps spasticity should be studied.