Muscle
Vastus lateralis
Large lateral contributor to knee extension
High-yield
Vastus lateralis is usually described as the largest quadriceps component. It works with the other heads to guide the patella and control loading, including when the knee bends under body weight.
Overview
This broad quadriceps muscle occupies the outer thigh. It starts on the proximal femur and adjoining shaft, then joins the extensor tissues around the patella to help straighten and control the knee.
Reference facts
- Origin
- Greater trochanter, proximal intertrochanteric/gluteal region, lateral linea aspera and adjoining intermuscular septum
- Insertion
- Base and lateral border of the patella through quadriceps tendon and retinacular tissues; onward to the tibial tuberosity through the patellar ligament
- Action
- Extends the knee and contributes to patellar control with the rest of the quadriceps
- Innervation
- Muscular branches of the femoral nerve, conventionally L2-L4
- Blood supply
- Predominantly lateral circumflex femoral branches, with profunda femoris perforating contributions
Clinical correlation
For most infants, vaccination guidance recommends the anterolateral thigh over this muscle because it offers suitable muscle mass. That recommendation depends on correct anatomical placement; it does not mean every part of the thigh is an equivalent injection site.
Frequently asked questions
What does the vastus lateralis do?
The vastus lateralis extends the knee and contributes to patellar control with the rest of the quadriceps.
What nerve innervates the vastus lateralis?
The vastus lateralis is innervated by the muscular branches of the femoral nerve, conventionally L2-L4.
Where does the vastus lateralis attach?
Origin: Greater trochanter, proximal intertrochanteric/gluteal region, lateral linea aspera and adjoining intermuscular septum. Insertion: Base and lateral border of the patella through quadriceps tendon and retinacular tissues; onward to the tibial tuberosity through the patellar ligament.
What is the blood supply of the vastus lateralis?
Predominantly lateral circumflex femoral branches, with profunda femoris perforating contributions.