GENERAL INFORMATION
The quadriceps femoris is a group of four muscles located in the anterior compartment of the thigh. It is the largest muscle group in the body and plays a key role in knee extension and hip flexion. The four muscles that make up the quadriceps femoris are the rectus femoris, vastus lateralis, vastus medialis, as well as vastus intermedius.
ORIGIN
- Rectus femoris: Anterior inferior iliac spine (AIIS) of the pelvis.
- Vastus lateralis: Greater trochanter of the femur and the lateral lip of the linea aspera.
- Vastus medialis: Intertrochanteric line and the medial lip of the linea aspera.
- Vastus intermedius: Anterior and lateral surfaces of the femur.
INSERTION POINT
All four muscles of the quadriceps femoris group converge to form a common tendon called the quadriceps tendon. The quadriceps tendon inserts onto the patella and continues as the patellar ligament, which attaches to the tibial tuberosity.
MAJOR ARTERIES
The quadriceps femoris is primarily supplied with blood by the femoral artery and its branches, including the deep femoral artery. These arteries provide the necessary oxygen as well as nutrients for muscle function.
NEURAL INNERVATION
The quadriceps femoris muscles are innervated by the femoral nerve, which arises from the lumbar plexus. The femoral nerve supplies motor innervation to the quadriceps muscles, allowing for muscle activation and control.
TRIGGER POINT
Trigger points of quadriceps femoris can develop in the quadriceps muscles due to muscle tension, overuse, or injury. These trigger points may cause pain and discomfort in the thigh and can refer pain to other areas, such as the knee or hip.
CONCENTRIC FUNCTION
The primary function of the quadriceps femoris is concentric contraction, which produces knee extension. It works to straighten the knee joint, allowing for activities such as walking, running, jumping, as well as squatting.
ECCENTRIC FUNCTION
The quadriceps femoris also functions eccentrically to control knee flexion, especially during activities that involve descending stairs or lowering the body into a squatting position. Eccentric contraction helps decelerate the movement and provide stability to the knee joint.
ISOMETRIC FUNCTION
The quadriceps femoris muscles can also contract isometrically to stabilise the knee joint during activities such as standing or maintaining a fixed position.
RELATED MUSCLE-SCIENTIFIC NAMES
- Rectus femoris (Musculus rectus femoris)
- Vastus lateralis (Musculus vastus lateralis)
- Vastus medialis (Musculus vastus medialis)
- Vastus intermedius (Musculus vastus intermedius)
ANTAGONIST
The primary antagonist to the quadriceps femoris is the hamstring muscle group, which includes the biceps femoris, semitendinosus, and semimembranosus. The hamstrings flex the knee joint while the quadriceps extend it, creating a reciprocal relationship for joint movement as well as stability.
COMMON INJURIES
- Quadriceps strain or tear: Sudden, forceful movements, overstretching, or direct trauma can cause muscle fibre damage.
- Tendonitis: Inflammation of the quadriceps tendons, often due to overuse.
- Patellar dislocation: Displacement of the kneecap from its normal position.
- Quadriceps tendinopathy: Degeneration of the quadriceps tendons due to chronic overuse.
EXERCISES
- Squats: A compound exercise that targets the quadriceps femoris and other lower body muscles.
- Lunges: Engage the quadriceps and improve lower limb strength and stability.
- Leg presses: Focus on strengthening the quadriceps as well as other lower body muscles.
- Leg extensions: Isolate the quadriceps for targeted strengthening.
- Step-ups: Enhance quadriceps strength and functional movement.
STRETCHES
- Standing quadriceps stretch: Stand upright and pull one foot towards the buttocks to stretch the quadriceps.
- Seated quadriceps stretch: Sit with legs extended and pull one foot towards the buttocks to stretch the quadriceps.
- Lying quadriceps stretch: Lie on the stomach and pull one foot towards the buttocks.
- Sartorius stretch: Sit with one leg extended and the other leg crossed over, pulling the knee towards the opposite shoulder.
- Hip flexor stretches: Improve flexibility in the hip flexors, indirectly benefiting the quadriceps.