PT661 myology

Gracilis

• origin: body and inferior ramus of pubis

• insertion: superior part of medial tibia

• innervation: obturator n.

• action: hip adduction, knee flexion, medial rotation

Sartorious

• origin: anterior superior iliac spine (ASIS)

• insertion: superior part of medial tibia (pes anserine)

• innervation: femoral n.

• action: hip flexion, adduction, and external rotation; knee flexion

rectus femoris

• origin: anterior inferior iliac spine (AIIS)

• insertion: base of patella via the quadriceps tendon, tibial tuberosity via patellar ligament

• innervation: femoral n.

• action: extension of knee, helps iliopsoas flex hip joint, stabilizes the hip

Vastus intermedius

• origin: anterior and lateral surfaces of shaft of femur

• insertion: base of patella via the quadriceps tendon, tibial tuberosity via patellar ligament

• innervation: femoral n.

• action: extends the knee

vastus lateralis

• origin: greater trochanter and lateral lip of linea aspera

• insertion: base of patella via the quadriceps tendon, tibial tuberosity via patellar ligament, tibia via aponeurosis

• innervation: femoral n.

• action: extends knee

vastus medialis

• origin: intertrochanteric line and medial lip of linea aspera

• insertion: base of patella via the quadriceps tendon, tibial tuberosity via patellar ligament, tibia via aponeurosis

• innervation: femoral n.

• action: extends knee

popliteus

• origin: lateral surface of lateral condyle of femur and lateral meniscus

• insertion: posterior surface of tibia, superior to soleal line

• innervation: tibial n.

• action: weak knee flexion, unlocks in by laterally rotating femur on fixed tibia, medially rotate tibia in open kinetic chain

Biceps femoris

• origin:

  • long head: ischial tuberosity

  • short head: linea aspera and supracondylar line of femur

• insertion: lateral head of fibula

• innervation:

  • long head: tibial division of sciatic n.

  • short head: common fibular division of sciatic n.

• action: flexes knee, rotates knee laterally when flexed, extends hip

Semimembranosus

• origin: ischial tuberosity

• insertion: posterior part of medial condyle of tibia

• innervation: tibial division of sciatic n.

• action: extend hip, flexes knee and rotates medially, extends trunk when knee and hip are flexed

Semitendinosus

• origin: ischial tuberosity

• insertion: medial surface of superior part of tibia

• innervation: tibial division of sciatic n.

• action: extends hip, flexes knee and rotates medially, when knee and hip are flexed, extend trunk