The Role of Vastus Lateralis in Knee Extension

The vastus lateralis is a muscle on the outside part of the thigh. Injuries to the muscle include strains, tendinitis, femoral nerve compression, and others. Can rehabilitation like heat and ice, massage, and strength and mobility exercises help individuals return to normal activities and function?

Vastus Lateralis Muscle

The vastus lateralis is the largest of the four quadriceps muscles on the thigh’s outer portion. The vastus lateralis helps extend the knee joint and maintain the knee position when walking or running. The vastus lateralis functions to work with the other quad muscles to help extend the knee joint.

Anatomy

Most muscles are attached to bone points of attachment, called the origin and insertion points. The vastus lateralis origin and insertion points are as follows (Vieira, EPL. 2017)

Origin

• The origin is on the upper inter-trochanteric line of the femur or thigh bone.
• It also arises from the base of the greater trochanter and the linea aspera, the supracondylar ridge, and the lateral intermuscular septum.

Insertion

• From its origin, the muscle courses down the lateral thigh and inserts as part of the lateral quadriceps tendon on the tibial tubercle, an elevated portion of the upper shin.
• The muscle is a large, flat structure with different attachments and a flat aponeurosis or sheath of connective tissue on the outer thigh.

1. The femoral nerve from lower back levels two, three, and four controls or innervates the muscle.
2. Blood supply to the muscle goes through the lateral circumflex femoral artery of the upper thigh.

Function

The muscle works with the other quadriceps muscles to extend or straighten the knee. The quads are responsible for functional activities like walking, running, climbing stairs, and getting up from a seated position. The vastus lateralis and the iliotibial band, which courses down the lateral thigh next to this muscle, form the lateral wall of the thigh. The vastus lateralis is on the opposite side of the vastus medialis muscle on the inner portion of the thigh. These muscles work together to maintain the appropriate position of the patella/kneecap in the femoral groove of the thigh bone. Malfunctioning these muscles properly can lead to knee pain from patellofemoral stress syndrome. (American Academy of Orthopaedic Surgeons, 2024)

Conditions

Many different injuries and conditions can affect the vastus lateralis and quad muscles, especially in athletes or active individuals. These injuries can cause vastus lateralis pain and other problems. (Timothy J. Von Fange, 2024) Some of the injuries and conditions include:

Patellofemoral Stress Syndrome – PFSS

• This occurs when the kneecap tracks improperly in the femoral groove of the knee joint.
• This leads to pain and difficulty when walking and running.

Vastus Lateralis Strain

• A sudden force on the thigh can cause the quad muscle to be strained.
• If the vastus lateralis suffers a pull injury, individuals may have pain, muscle swelling, thigh bruising, and walking difficulties.

Patellar Tendinitis

• Irritation of the quad tendon that courses over the kneecap can cause patellar tendinitis.

Femoral Nerve Compression Weakness

• The femoral nerve may become pinched or irritated from a herniated disc, lumbar stenosis, or arthritis.
• Pain, numbness, tingling, or weakness in the thigh may result.

Iliotibial Band Friction Syndrome

• Tight or weak muscles can irritate the IT band, and the vastus lateralis muscle can be affected.

Injury Rehabilitation

Injury to the vastus lateralis or quad muscles can cause pain, swelling of the thigh, or limited walking ability. Various treatments are available to help expedite recovery. A primary healthcare provider may recommend working with a physical therapy team. Self-care techniques can include:

Heat and Ice

• Ice may be applied to the lateral thigh the first few days after injury to control pain and decrease swelling and inflammation.
• Ice should be applied for 10 to 15 minutes.
• Individuals may switch to heat two to three days after to promote circulation and improve tissue mobility.
• Heat should be applied for 10 to 15 minutes.

Massage

• Massage can help decrease pain and promote circulation.
• Massage techniques can improve tissue mobility before stretching to help improve quadriceps motion.

Exercises and Stretching

A physical therapy team will prescribe certain exercises and stretches to help regain strength and range of motion. After an injury, quad stretching can improve the mobility and function of the muscle group.

Prone Towel Quad Stretch

• Lie on your stomach and place a towel or strap around the ankle.
• Bend the knee up, and gently pull on the towel to bend the knee fully.
• A pulling sensation should be felt in the front of the thigh.
• Hold the stretch for 30 seconds and release.
• Repeat three times.

Half-kneeling Quad and Hip Flexor Stretch

• Kneel on one knee.
• Slowly move forward until a stretch is felt in the front of the hip and thigh.
• Hold this position for 30 seconds.
• Relax back to the starting position.
• Repeat three times.

Back Exercises

If femoral nerve irritation coming from the lower back is causing thigh pain or weakness, exercises to release the nerve may be helpful and can include:

• Prone press-ups
• Supine lumbar flexion
• Lumbar side glides

The exercises are designed to relieve pressure on the lumbar nerve, and postural correction exercises may be performed to maintain decompression.

Strengthening

Weakness to the vastus laterals and quads may be causing injury, and strengthening exercises may be prescribed during rehabilitation and can include:

• Hip-strengthening exercises
• Straight leg raises
• Leg extension exercises
• Lunges
• Squats

Strengthening exercises should be done two to four times weekly with appropriate rest between sessions.

Functional Training

A physical therapist may recommend functional training to restore normal function. (Ramírez-delaCruz, M. et al., 2022)

• Balance exercises and sport-specific plyometric training may be recommended to ensure the quad functions normally.
• Most quadriceps and vastus lateralis muscle injuries heal within six to eight weeks.
• Recovery may be shorter or longer depending on the nature of the injury.

Injury Medical Chiropractic and Functional Medicine Clinic

By understanding the anatomy and function of the vastus lateralis muscle, a healthcare provider can help individuals understand their specific injury and develop a treatment program to rehabilitate the muscle properly. At Injury Medical Chiropractic and Functional Medicine Clinic, we focus on what works for you and strive to develop fitness and better the body through research methods and total wellness programs. These natural programs use the body’s ability to achieve improvement goals, and athletes can condition themselves to excel in their sport through proper fitness and nutrition. Our providers use an integrated approach to create personalized programs, often including Functional Medicine, Acupuncture, Electro-Acupuncture, and Sports Medicine principles.

Knee Injury Chiropractor

References

Vieira EPL. (2017). Anatomic study of the portions long and oblique of the vastus lateralis and vastus medialis muscles. J Morphol Sci., 28(4), 0-. www.jms.periodikos.com.br/article/587cb49f7f8c9d0d058b47a1/pdf/jms-28-4-587cb49f7f8c9d0d058b47a1.pdf

American Academy of Orthopaedic Surgeons. (2024). Patellofemoral pain syndrome. orthoinfo.aaos.org/en/diseases–conditions/patellofemoral-pain-syndrome/

Timothy J Von Fange. (2024). Quadriceps muscle and tendon injuries. UpToDate. www.uptodate.com/contents/quadriceps-muscle-and-tendon-injuries/print

Ramírez-delaCruz, M., Bravo-Sánchez, A., Esteban-García, P., Jiménez, F., & Abián-Vicén, J. (2022). Effects of Plyometric Training on Lower Body Muscle Architecture, Tendon Structure, Stiffness, and Physical Performance: A Systematic Review and Meta-analysis. Sports medicine – open, 8(1), 40. doi.org/10.1186/s40798-022-00431-0