MSK - Muscles of the Posterior Compartments of the Thigh

Question 1

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

Answer 1

Hamstrings

Question 2

What is the innvervation of the hamstrings?

Answer 2

The Sciatic Nerve

Question 3

What is the name of the muscle highlighted in red?

How many heads does it have?

Answer 3

Biceps Femoris

2

Question 4

Which side of the posterior knee can the short head of the Biceps Femoris be felt?

Answer 4

Lateral

Question 5

What are the attachments of the Biceps Femoris?

Answer 5

Long Head - Originates from the ischial tuberosity of the pelvis

Short Head - Originates from the linea aspera on posterior surface of the femur

**Together - **The heads form a tendon, which inserts into the head of the fibula

Question 6

What is the main action of the Biceps Femoris?

What else does the Biceps Femoris do?

Answer 6

Main - Flexion at the knee

Also extends the leg at the hip and laterally rotates the hip and the knee

Question 7

What is the innervation of the Biceps Femoris?

Answer 7

Sciatic Nerve

Question 8

What is the name of the muscle highlighted in blue?

Answer 8

Semitendinosus

Question 9

What are the attachments of the Semitendinosus?

Answer 9

It originates from the ischial tuberosity of the pelvis, and attaches to the medial surface of the tibia

Question 10

What are the actions of the Semitendinosus?

Answer 10

Flexion of the leg at the knee joint

Extension of thigh at the hip

Medially rotates the thigh at the hip join and the leg at the knee joint

Question 11

What is the innervation of the Semitendinosus?

Answer 11

Sciatic Nerve

Question 12

What is the name of the muscle highlighted in yellow?

Answer 12

Semimembranous

Question 13

What are the attachments of the Semimembranosus?

Answer 13

It originates from the ischial tuberosity, but does so more superiorly than the semitendinosus and biceps femoris. It attaches to the medial tibial condyle

Question 14

What are the actions of the Semimembranosus?

Answer 14

Flexion of the leg at the knee joint

Extension of the thigh at the hip

Medially rotates the thigh at the hip joint and the leg at the knee joint

Question 15

What is the innervation of the Semimembranosus?

Answer 15

Sciatic Nerve

Question 16

What does a hamstring strain refer to?

How are they often injured?

Answer 16

**Excessive stretch **or **tearing **of the muscle fibres

During sports that involve kicking or running

Question 17

What is damage to the muscle fibers also likely to damage?

What would this produce?

How would it be contained?

Answer 17

Surrounding blood vessels

Produces a haematoma

Contained by overlyng fascia lata

Question 18

How should a hamstring muscle strain be treated?

Answer 18

RICE Protocol

Rest

Ice

Compression

Elevation

Question 19

What has happened here?

Answer 19

Avulsion Fracture of the Ischial Tuberosity

Question 20

What is an avulsion fracture?

Answer 20

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

Question 21

How does an avulsion fracture of the ischial tuberosity occur?

During what activities does an avulsion fracture usually occur?

Answer 21

Hamstring tendons “tear off” a piece of ischial tuberosity

During sports that require rapid contraction and relaxation of the muscles