Which muscle has the action of extending the knee and originates from the linea aspera of the femur?

Which muscle has the action of extending the knee and originates from the linea aspera of the femur?

• A. Vastus Medialis
• B. Vastus Lateralis
• C. Tibialis Anterior
• D. Gastrocnemius

Answer: (A)

Knee extension is carried out by the quadriceps femoris group, which pull on the patella to straighten the leg. The vastus medialis attaches along the medial part of the linea aspera on the femur (medial lip), so its line of pull supports extending the knee and also helps stabilize the patella medially during extension. The other muscles listed either act on different joints (tibialis anterior on the ankle) or have different attachment patterns (vastus lateralis attaches to the lateral lip of the linea aspera and also extends the knee, while gastrocnemius crosses the knee but primarily flexes the knee and plantarflexes the foot). Therefore, the muscle that both extends the knee and originates from the linea aspera on the femur is vastus medialis.

Knee extension is carried out by the quadriceps femoris group, which pull on the patella to straighten the leg. The vastus medialis attaches along the medial part of the linea aspera on the femur (medial lip), so its line of pull supports extending the knee and also helps stabilize the patella medially during extension. The other muscles listed either act on different joints (tibialis anterior on the ankle) or have different attachment patterns (vastus lateralis attaches to the lateral lip of the linea aspera and also extends the knee, while gastrocnemius crosses the knee but primarily flexes the knee and plantarflexes the foot). Therefore, the muscle that both extends the knee and originates from the linea aspera on the femur is vastus medialis.