Vastus Lateralis Muscle

Vastus Lateralis Muscle Anatomy

The vastus lateralis muscle is located on the lateral side of the thigh. This muscle is the largest of the quadriceps muscle which includes: rectus femoris, vastus intermedius, and vastus medialis. Together, the quadriceps act on the knee and hip to promote movement as well as strength and stability.

Origin

It originates from the,

• upper aspect of the intertrochanteric line,
• base of the greater trochanter and onto its anterior surface,
• from the proximal portion of the lateral lip of the linea aspera,
• lateral intermuscular septum.

Insertion

It inserts into the lateral side of the quadriceps tendon, joining with rectus femoris, vastus medialis, and vastus intermedius muscles, enveloping the patella, then by the patellar ligament into the tibial tuberosity.

Nerve supply

The Posterior division of the femoral nerve (L3, L4) supplies the muscle.

Blood supply

• The superior medial artery, which is a branch of the lateral circumflex femoral artery.
• The inferior medial artery, a branch of the artery of the quadriceps.
• The lateral artery, which is actually the first perforator of the deep femoral artery.

Action

It acts as an extensor of the knee.

Functional Contribution of the muscle

In everyday life, the quadriceps muscle group as a whole allows a person to stand up from sitting, walk up or down stairs along with basic walking and running. These muscles are not active while standing with knees fully extending, but become active during the heel-strike and toe-off phases of gait.

Strengthening Exercises:

1. Step-up Exercises

• Start with a box height that is comfortable for you to step up on.
• Be sure to keep your knee in alignment with your second toe.
• Step up and keep your pelvis level and your knee in alignment.
• Be sure to engage the buttocks muscles and fully lock out the knee.
• Return slowly back down to the ground.
• The focus should be on the slow eccentric (lowering) back to the ground for 1 second up and 3 seconds down.
• Perform 2 sets of 15-20 repetitions once per day.

Stretching Exercises:

• From a forward lunge position, flex the forward knee with the sole of the foot flat on the floor.
• Flex the knee of the rearward leg towards the buttocks, grasp the foot with your hand behind you and apply a medial rotation to the hip by pushing the foot away from the midline of the body.
• To gently increase the stretch, tilt the pelvis posteriorly and keeping the chest upright, lean into the forward hip.
• You may want to perform this stretch next to a wall or chair to aid in balance

Related pathology:

Some evidence has shown that in patients with patellofemoral pain syndrome vastus lateralis contracts prematurely when compared with vastus medialis which has been hypothesised to be a cause of knee pain. In more recent studies this theory has not been clinically proven and vastus lateralis/medialis timing has been shown to be uneven in healthy test subjects.

For More Lower Limb Muscle related post