Posterior compartment

· hamstring compartment

· separated from extensor compartment by lateral intermuscular septum

· not separated from adductor compartment

Posterior femoral cutaneous nerve

· branch of sciatic plexus (S2,3)

· runs vertically down just beneath fascia lata

hamstring muscles

Semimembranosus

Origin

· ischial tuberosity

· lateral part of upper smooth part

Path

· long flat ribbon-like tendon for 15 cm from origin

· replaced by muscle

· semitendinosus tendon lies on it

Insertion

· medial condyle of tibia

· 4 expansions

· oblique popliteal ligament to lateral condyle of femur

· into posterior capsule and posterior horn of medial meniscus

· anteriorly under superficial MCL to medial tibia

· over popliteus to soleal line

Semitendinosus

Origin

· ischial tuberosity

· medial part of upper smoth facet

· together with long head of biceps

Path

· proximal

· fleshy belly

· tendon of semimembranosus lies on it

· distal

· muscle becomes tendon

· lies on belly of semimembranosus

Insertion

· pes anserinus

· behind gracilis

Biceps femoris

Origin

· long head from ischial tuberosity

· medial part of upper smoth facet

· together with semitendinosus

· short head from femur

· linea aspera and upper part of lateral supracondylar line

Path

· 2 heads fuse into one tendon

Insertion

· head of fibula

· in front of styloid process

Sciatic nerve

· runs through hamstring component

· deep to long head of biceps

· on adductor magnus

· divides into tibial and common peroneal components

· handsbreadth above knee joint

· sometimes as high as pelvis

· supplied by artery of sciatic nerve

· branch of inferior gluteal a

· supplies hamstrings

· by tibial component (L5,S1)

· together with hamstring part of adductor magnus

· EXCEPT short head of biceps

· common peroneal component (L5,S1)