Knee Flexors

Question 1

Biceps Femoris

Answer 1

Origins: Long head- inferomedial aspect of ischial tuberosity
Short head- low1/2 of lat linea aspera, upp1/2 of lat supracondylar line of femur
Insertion: head of fibula

Innervation: Sciatic L5-S2

Only muscle to lat rot knee

Question 2

Semitendinosus

Answer 2

Origin: inferomedial aspect of ischial tuberosity
Insertion: anteromedial aspect of prox. Tibia

Innervation: Sciatic L5-S2

Med rots knee

Question 3

Semimembranosus

Answer 3

Origin: superolateral aspect of ischial tuberosity
Insertion: posteromedial surface of med tib condyle (crosses knee)

Innervation: Sciatic L5-S2

Med rots knee

Question 4

Popliteus

Small/flat/deep/post muscle part of popliteal fossa floor

Answer 4

Origin: lat fem condyle
Insertion: prox surface of post tibia

Innervation: Tibial L4-S1

Unlocks ext knee, med rot knee

Question 5

Plantaris (weak)

Not present in everyone

Answer 5

Origin: lat supracondylar line, above lat head of gastroc
Insertion: sup aspect of med,post calcaneum (crosses lat->med)

Innervation: Tibial L4-S1

Weak PF

Question 6

Gastrocnemius

Answer 6

Origins: heads of med and lat fem condyles posteriorly
Insertion: Achilles’ tendon into post-sup calcaneus (heel)

Innervation: Tibial S1-2

PF

Question 7

Sartorius

Answer 7

Origin: ASIS
Insertion: superomedial part of tibia (in front of semitend/grac)

Innervation: Femoral L2-3

Question 8

Gracilis

Answer 8

Origin: body and inferior ramus of pubis
Insertion: med surface shaft of tibia (between sart/semitend)

Innervation: Obturator L2-3