Knee Extension

Electrode Placement
Application Instruction by Dr. Lucinda Baker

Electrode placement for knee extension. The patella is marked with a circle, distally. The large electrodes are placed along the thigh. The proximal electrode is very proximal and towards the lateral side. The distal electrode is placed either at midline, as shown here, or slightly to the medial side. Too much medial a placement of the distal electrode can create a powerful Vastus Medialis cramp. If this occurs, keep the distal electrode midline to slightly lateral.

Knee Extension

Video Instruction
Audio Transcript:

Electrode placement for knee extension. The patella is marked with a circle, distally. The large electrodes are placed along the thigh. The proximal electrode is very proximal and towards the lateral side. The distal electrode is placed either at midline, as shown here, or slightly to the medial side. Too much medial a placement of the distal electrode can create a powerful Vastus Medialis cramp. If this occurs, keep the distal electrode midline to slightly lateral.

Knee Extension

Muscle Anatomy

Muscles involved in knee extension:

Rectus Femoris
Origin: Straight head from anterior inferior iliac spine. Reflected head from groove just above acetabulum
Insertion: Base of Patella

Vastus Intermedius
Origin: Superior half of anterior and Lateral surfaces of femur
Insertion: Lateral border of Patella

Vastus Medialis
Origin: Superior half of anterior and medial surfaces of femur
Insertion: Medial condyle of tibia

Vastus Lateralis
Origin: Superior half of anterior and Lateral surfaces of femur
Insertion: Lateral border and Base of Patella

Sartorius
Origin: Anterior Superior iliac spine
Insertion: Supero-medial tibia
Other actions: Hip flexion, lateral hip rotation

Knee Extension

Nerve Anatomy

Nerves involved in knee extension:

Rectus Femoris
Nerve innervation: Muscular branches of femoral nerve
Nerve root: L2, L3, L4

Vastus Intermedius
Nerve innervation: Muscular branches of femoral nerve
Nerve root: L2, L3, L4

Vastus Medialis
Nerve innervation: Muscular branches of femoral nerve
Nerve root: L2, L3, L4

Vastus Lateralis
Nerve innervation: Muscular branches of femoral nerve
Nerve root: L2, L3, L4

Sartorius
Nerve innervation: Femoral nerve
Nerve root: L2, L3, L4