Knee Muscles

Origin: AIIS

Insertion: Tibial tuberosity via patellar tendon

Action: Hip flexion and knee extension

• Vastus lateralis

• Vastus medialis

• Sartorius

• Rectus femoris

Origin: Linea aspera

Insertion: Tibial tuberosity via patellar tendon

Action: Knee extension

• Vastus lateralis

• Vastus medialis

• Sartorius

• Rectus femoris

Origin: Linea aspera

Insertion: Tibial tuberosity via patellar tendon

Action: Knee extension

• Vastus lateralis

• Vastus medialis

• Sartorius

• Rectus femoris

Origin: Anterior femur 
Insertion: Tibial tuberosity via patellar tendon 
Action: Knee extension

• Vastus lateralis

• Vastus medialis

• Vastus intermedialis

• Rectus femoris

Origin: Ischial tuberosity 
Insertion: Anteromedial surface of proximal tibia 
Action: Hip extension and knee flexion

• Semimembranosus

• Semitendinosus

• Biceps femoris long head 

• Biceps femoris short head 

Origin: Ischial tuberosity 
Insertion: Posterior surface of medial condyle of tibia Action: Hip extension and knee flexion

• Semimembranosus

• Semitendinosus

• Biceps femoris long head

• Biceps femoris short head

Origin: Ischial tuberosity  
Insertion: Fibular head 
Action: Hip extension and knee flexion 

• Semimembranosus

• Semitendinosus

• Biceps femoris long head

• Biceps femoris short head

Origin: Lateral lip of linea aspera 
Insertion: Fibular head 
Action: Knee flexion

• Semimembranosus

• Semitendinosus

• Biceps femoris long head

• Biceps femoris short head

Origin: Lateral condyle of femur

Insertion: Posterior medial condyle of tibia

Action: Initiates knee flexion

• Popliteus

• Gastrocnemius

• Gracilis

• Tensor fascia latae

Origin: Medial and lateral condyles of femur

Insertion: Posterior calcaneus

Action: Knee flexion and ankle plantar flexion

• Popliteus

• Gastrocnemius

• Gracilis

• Tensor fascia latae