Knee Movement and Function

Question 1

What are the origins and insertions of the knee flexors?

Answer 1

Semimembranosus: Origin @ the ischial tuberosity and inserts @ the medial condyle of the tibia

Semitendinosus: Origin @ the ischial tuberosity and inserts @ the medial aspect of the proximal part of the tibia (PES ANSERINUS)

Long Head of Biceps Femoris: Origin @ the ischial tuberosity and inserts @ the head of the fibula

Short Head of Biceps Femoris: Origin @ the linea aspera and lateral supracondylar line of the femur and inserts @ the head of the fibula

Medial Head of Gastrocnemius: Origin @ the medial condyle and the popliteal surface of the femur and inserts @ the calcaneal tendon

Lateral Head of Gastrocnemius: Origin @ the lateral condyle and the lateral supracondylar line of the femur, inserts @ the calcaneal tendon

Sartorius: Origin @ the ASIS and inserts @ the medial aspect of the proximal part of the tibia (PES ANSERINUS)

Gracilis: Origin @ the body of the and pubis and inserts @ the medial aspect of the proximal part of the tibia (PES ANSERINUS)

Popliteus: originates from the femur and the posterior horn of the lateral meniscus, and inserts on the proximal tibia.

Question 2

What are the origins and insertions of the knee extensors?

Answer 2

Quads:

Vastus Medialis: Inserts @ the intertrochanteric line and medial to the linea aspera and extending inferiorly to the medial supracondylar line. Inserts @ the tibial tuberosity via the quads tendon and patellar ligament

Vastus Intermedius: Inserts @ the anterior and lateral surfaces of the body of the femur. Inserts @ the tibial tuberosity via the quads tendon and patellar ligament

Vastus Lateralis: Origin @ the intertrochanteric line, the greater trochanter, gluteal tuberosity and lateral to the linea aspera of the femur. Inserts @ the tibial tuberosity via the quads tendon and patellar ligament

Rectus Femoris: Origin @ the ASIS and inserts @ the tibial tuberosity via the quadriceps tendon/patellar tendon

Tensor Fasciae Latae: Origin @ the ASIS and inserts fully into the IT band

Question 3

What are the origins and insertions of the knee medial rotators?

Answer 3

Popliteus: Origin @ the groove of the popliteus muscle and inserts @ the posterior surface of the tibia (generates rotation but also pulls the meniscus)

The medial muscles:
Semitendinosus
Semimembranosus
Sartorius
Gracilis

Question 4

What are the origins and insertions of the knee lateral rotators?

Answer 4

Long Head of Biceps Femoris:
Origin @ the ischial tuberosity and inserts @ the head of the fibula

Short Head of Biceps Femoris:
Origin @ the lower half of the linea aspera and the lateral supracondylar line. Inserts @ the head of the fibula