Posterior Hip Musculature

Question 1

Semitendinosus

Answer 1

Origin
- Ischial tuberosity
Insertion
- Anteromedial aspect of the tibial shaft
Action
- Extends hip
- Flexes knee
- Medially rotates the tibia (open chain)
Nerve
- Tibial portion of sciatic
- L5, S1-2

Question 2

Semimembranosus

Answer 2

Origin
- Ischial tuberosity
Insertion
- Posterior medial aspect of the medial tibial condyle
Action
- Extends hip
- Flexes knee
- Medially rotates the tibia (open chain)
Nerve
- Tibial portion of sciatic
- L5, S1-2

Question 3

Biceps Femoris

Answer 3

Origin
- Long head: ischial tuberosity
- Short head: lateral lip of the linea aspera
Insertion
- Head of fibula
Action
- Flexes knee
- Extends hip (long head)
- Laterally rotates tibia (open chain)
Nerve
- Long head: tibial portion of sciatic
- Short head: common peroneal of sciatic