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 is the proximal attachment of the long head of the biceps femoris?

Answer 9

Ischial tuberosity

Question 10

What is the proximal attachment of the short head of the biceps femoris?

Answer 10

Linea aspera and lateral supracondylar line of the femur

Question 11

What is the distal attachment of the biceps femoris?

Answer 11

Lateral side of the head of the fibula

Question 12

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

Answer 12

It is split by the fibular collateral ligament of the knee

Question 13

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

Answer 13

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

Question 14

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

Answer 14

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

Question 15

What is the arterial supply of the biceps femoris?

Answer 15

Perforating arteries of the deep femoral artery

Question 16

What is the main action of the biceps femoris?

Answer 16

Flexes leg and laterally rotates it when the knee is flexed

Extends thigh

Question 17

What can be said of the semitendinosus?

Answer 17

It is a largely tendinous muscle

Question 18

Where does the semitendinosus muscle lie?

Answer 18

Medially to the biceps femoris

Question 19

What does the semitendinosus cover?

Answer 19

The majority of the semimembranosus

Question 20

What is the proximal attachment of the semitendinosus?

Answer 20

Ischial tuberosity

Question 21

What is the distal attachment of the semitendinosus?

Answer 21

Medial surface of the superior part of tibia

Question 22

What do the semitendinosus and semimembranosus share?

Answer 22

Innervation
Action
Arterial supply
Proximal attachment

Question 23

What shape is the semimembranosus?

Answer 23

Flattened, broad

Question 24

Where is the semimembranosus muscle located?

Answer 24

Underneath the semitendinosus

Question 25

What is the proximal attachment of the semimembranosus?

Answer 25

Ischial tuberosity

Question 26

What is the distal attachment of the semimembranosus?

Answer 26

Posterior part of medial condyle of tibia

Question 27

What does the reflected attachment of the semimembranosus form

Answer 27

The oblique popliteal ligament to lateral femoral condyle

Question 28

What is the innervation of the semitendinosus and semimembranosus?

Answer 28

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

Question 29

What is the arterial supply of the semitendinosus and semimembranosus?

Answer 29

Perforating arteries of deep femoral arteries

Question 30

What is the main action of thesemitendinosus and semimembranosus?

Answer 30

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

Question 31

What does a hamstring strain refer to?

Answer 31

Excessive stretch or tearing of the muscle fibres

Question 32

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

Answer 32

Rupture surrounding blood vessels, causing a haemotoma

Question 33

What contains a haemotoma formed by hamstring strain?

Answer 33

The overlying fascia lata

Question 34

When does an avulsion fracture occur?

Answer 34

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

Question 35

What happens in an avulsion fracture of the ischial tuberosity?

Answer 35

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