Muscles of the posterior compartment

Question 1

Describe the muscles of the posterior compartment of the thigh

Name these muscles

Answer 1

Collectively known as the hamstrings they act to extend the hip and flex the knee. They are all innervated by the sicatic nerve (L4-S3)

Biceps femoris
Semitendenous
Semimembranous

Question 2

What is biceps femoris

What innervates it?

Answer 2

Most lateral muscle in the posterior compartment.Contains tow heads, the common tendon can be felt on the lateral posterior knee

Sciatic nerve

Question 3

What are the attachments of the biceps femoris

What are its actions

Answer 3

Long head- ischial tuberosity of pelvis,
short head- linea aspera on posterior femur
Insert at head of fibula

Flexion of the knee. Also extends thigh at hip and laterally rotates hip and knee

Question 4

What is semitendinous

What innervates it?

Answer 4

Largely tendinous msucle. Lie medially to the biceps femoris

Tibial part of sciatic nerve (L4-S3)

Question 5

What are its attchments of semitendinous

What are its actions?

Answer 5

Originates from the ischial tuberosity
attaches to the medial tibial tuberosity

Flexion of the leg at the knee joint, medially rotates the thigh at the hip joint adn the leg at the knee joint

Question 6

What is semimembranous

What innervates it?

Answer 6

Flat and broad muscle that lies under the semitendinousus

Tibial part of sciatic nerve (L4-S3)

Question 7

What is semimembranous attachments?

What are its actions?

Answer 7

Originates from ischial tuberosity
Inserts at medial tibial condyle

Flexes leg at knee joint.Extends the thigh at the hip. Medially rotates the thigh at the hip joint and the leg at the knee joint.

Question 8

What occurs during a hamstring strain?

Answer 8

Excessive stretching or tearing of the muscle fibres, often seen in running or kicking sports. Damage to these muscle fibres are likely to rupture the surrounding blood vessels producing a heamatoma