Posterior Thigh Muscles

Question 1

What are the muscles in the posterior compartment of the thigh known as?

Answer 1

The hamstrings

Question 2

What do the hamstrings consist of?

Answer 2

Biceps femoris Semitendinosus

Semimembranosus

Question 3

What do the hamstrings do as a group?

Answer 3

Extend at the hip and flex at the knee

Question 4

What are the hamstrings innervated by?

Answer 4

The sciatic nerve (L4-S3) as it descends through the thigh

Question 5

What to the hamstrings form?

Answer 5

Prominent tendons medially and laterally at the back of the knee

Question 6

What does the biceps femoris have?

Answer 6

Two heads, a long and a short

Question 7

Where does the biceps femoris lie?

Answer 7

More laterally

Question 8

Where can the common tendon of the two heads be felt?

Answer 8

Laterally at the posterior knee

Question 9

What happens to the biceps tendon at the lateral side of the head of the femur?

Answer 9

It is split by the fibular collateral ligament of the knee

Question 10

What is the innervation of the long head of the biceps femoris?

Answer 10

Tibial division of the sciatic nerve (L5, S1, S2)

Question 11

What is the innervation of the short head of the biceps femoris?

Answer 11

Common fibular division of the sciatic nerve (L5, S1, S2)

Question 12

What is the arterial supply of the biceps femoris?

Answer 12

Perforating arteries of the deep femoral artery

Question 13

What is the main action of the biceps femoris?

Answer 13

Flexes leg and laterally rotates it when the knee is flexed

Extends thigh

Question 14

What can be said of the semitendinosus?

Answer 14

It is a largely tendinous muscle

Question 15

Where does the semitendinosus muscle lie?

Answer 15

Medially to the biceps femoris

Question 16

What does the semitendinosus cover?

Answer 16

The majority of the semimembranosus

Question 17

What do the semitendinosus and semimembranosus share?

Answer 17

Innervation
Action
Arterial supply
Proximal attachment

Question 18

What shape is the semimembranosus?

Answer 18

Flattened, broad

Question 19

Where is the semimembranosus muscle located?

Answer 19

Underneath the semitendinosus

Question 20

What does the reflected attachment of the semimembranosus form

Answer 20

The oblique popliteal ligament to lateral femoral condyle

Question 21

What is the innervation of the semitendinosus and semimembranosus?

Answer 21

Tibial division of the sciatic nerve part of tibia (L5, S1, S2)

Question 22

What is the arterial supply of the semitendinosus and semimembranosus?

Answer 22

Perforating arteries of deep femoral arteries

Question 23

What is the main action of thesemitendinosus and semimembranosus?

Answer 23

Extend thigh
Flex leg and rotate it medially when knee is flexed
When knee and leg are flexed, can extend trunk

Question 24

What does a hamstring strain refer to?

Answer 24

Excessive stretch or tearing of the muscle fibres

Question 25

What is damage to the hamstring muscle fibres likely to do?

Answer 25

Rupture surrounding blood vessels, causing a haemotoma

Question 26

What contains a haemotoma formed by hamstring strain?

Answer 26

The overlying fascia lata

Question 27

When does an avulsion fracture occur?

Answer 27

When a fragment of bone breaks away from the main body of bone

Question 28

What happens in an avulsion fracture of the ischial tuberosity?

Answer 28

The hamstring tendons ‘tear off’ a piece of the ischial tuberosity