Lecture 6: Posterior Thigh and Popliteal Fossa

Question 1

What is the criteria for a muscle to be a “true” hamstring?

Answer 1

It must both flex the knee and extend the hip

Question 2

What two “hamstring” muscles are not true hamstrings?

Answer 2

The hamstring portion of the adductor magnus (does not cross the knee)

The short head of the biceps femoris (does not cross the hip)

Question 3

Where do all of the true hamstring muscles originate?

Answer 3

The ischial tuberosity

Question 4

What is the innervation for the true hamstrings?

Answer 4

Tibial Branch of the Sciatic Nerve

Question 5

Semitendinosus Muscle

What is its attachments?

Answer 5

Origin: Ischial Tuberosity

Insertion: Pes Anserinus (anteromedial aspect of superior tibia)

Posteromedial Aspect of thigh

Question 6

Semitendinosus Muscle

What is its action?

Answer 6

1. Extend Thigh
2. Flex Leg
3. Medially rotate flexed leg

Question 7

Semitendinosus Muscle

What is its innervation and blood supply?

Answer 7

Innervation: Tibial Division of Sciatic Nerve

Blood Supply: Perforating branches of Deep Femoral Artery and Inferior Gluteal Artery

Question 8

Semimembranosus Muscle

What is its attachments?

Answer 8

Origin: Ischial Tuberosity

Insertion: Posterior part of Medial Tibial Condyle

• Distal tendon divides into two parts
• Posteromedial Aspect of thigh*

Question 9

Semimembranosus Muscle

What is its action?

Answer 9

1. Extend Thigh
2. Flex Leg
3. Medially rotate flexed leg

Question 10

Semitendinosus Muscle

What is its innervation and blood supply?

Answer 10

Innervation: Tibial Division of Sciatic Nerve

Blood Supply: Perforating branches of Deep Femoral Artery and Inferior Gluteal Artery

Question 11

Long Head of Biceps Femoris Muscle

What is its attachments?

Answer 11

Origin: Ischial Tuberosity

Insertion: Lateral aspect of Fibular Head

Posterolateral aspect of thigh

Question 12

Long Head of Biceps Muscle

What is its action?

Answer 12

1. Extend Thigh
2. Flex Leg
3. Laterally rotate flexed leg

Question 13

Long Head of Biceps​ Muscle

What is its innervation and blood supply?

Answer 13

Innervation: Tibial Division of Sciatic Nerve

Blood Supply: Perforating branches of Deep Femoral Artery and Inferior Gluteal Artery

Question 14

Short Head of Biceps Femoris Muscle

What is its attachments?

Answer 14

Origin: Lateral lip of linea aspera and lateral supracondylar line

Insertion: Lateral aspect of Fibular Head

Posterolateral aspect of thigh

Question 15

Short Head of Biceps Muscle

What is its action?

Answer 15

1. Flex Leg
2. Laterally rotate flexed leg

Question 16

Short Head of Biceps​ Muscle

What is its innervation and blood supply?

Answer 16

Innervation: Common Fibular Division of Sciatic Nerve

Blood Supply: Perforating branches of Deep Femoral Artery and Inferior Gluteal Artery

Question 17

What three muscles insert to Pes Anserinus and what compartment do they belong to?

Answer 17

1. Sartorius Muscle (Anterior Compartment)
2. Gracilis Muscle (Medial Compartment)
3. Semitendinosus Muscle (Posterior Compartment)

Question 18

What ligament is Pes Anserinus superficial to?

Answer 18

Medial/tibial Collateral Ligament

Question 19

What is Pes Anserine Bursitis?

Answer 19

Inflammation of anserine bursa between Pes Anserinus and MCL (due to overuse or trauma)

-Constant pain aggravated by activity due to flexion and medial rotation of knee

Question 20

What are the differences between the different grades of avulsion fractures?

Answer 20

Avulsion Fracture: tendon or ligament pulls off a piece of the bone

• Grade I: small disruption with minor swelling and pain
  
  • Minimal loss of strength (if any)
• Grade II: partial tears with definite pain
  
  • Definite loss of strenth
• Grade III: complete tear with severe pain and hematoma
  
  • Complete loss of motor function

Question 21

What muscles do the perforating arteries supply?

Answer 21

• Posterior Thigh Muscles
  
  • ​​​​Semitendinosus Muscle
  • Semimembranosus Muscle
  • Biceps Femoris Muscle (both heads)
• Adductor Magnus Muscle

Peforating arteries pierce through Adductor muscles to go anterior to posterior

Question 22

What does the descending branch of the Lateral Circumflex Femoral Artery supply?

Answer 22

Genicular anastomosis

Question 23

What vessel gives rise to the Fibular Artery?

Answer 23

The posterior tibial artery

Question 24

What are the nerve roots of the Tibial Division of the Sciatic Nerve?

Answer 24

L4-S3

Question 25

What are the nerve roots of the Common Fibular Division of the Sciatic Nerve?

Answer 25

L4-S2

Question 26

What are the nerve roots of the hamstring muscles?

Answer 26

L5-S2

Question 27

What are the four borders of the popliteal fossa?

Answer 27

**Superomedially:** Semitendinosus and Semimembranosus **Superolaterally**: Biceps Femoris **Inferomedially**: Medial head of the gastrocnemius **Inferolaterally**: Lateral head of the gastrocnemius

Question 28

What are the contents of the popliteal fossa?

Answer 28

Superficial to Deep: * Nerves * Popliteal Vein and Lymph Nodes * Popliteal Artery and Branches

Question 29

What are the terminal branches of the Popliteal Artery?

Answer 29

Anterior Tibial Artery Posterior Tibial Artery

Question 30

Where does the Genicular Artery arise from? What does it supply?

Answer 30

From Femoral Artery in adductor canal Genicular anastomosis

Question 31

What are the two branches of the descending genicular artery?

Answer 31

The _Articular_ Branch and The _Saphenous_ Branch (*Both feed into genicular anastomosis at one point or another*)

Question 32

Which of the Genicular Arteries does not anastomose?

Answer 32

**Middle Genicular Artery**, which supplies the knee capsule

Question 33

What veins become the Popliteal Vein?

Answer 33

Anterior and Posterior Tibial Veins

Question 34

What nerve provides innervation to the entire posterior leg?

Answer 34

Tibial Nerve

Question 35

What nerve supplies the anterior and lateral compartments of the leg?

Answer 35

Common fibular nerve

Question 36

What does the common fibular nerve split into?

Answer 36

Superficial and Deep fibular nerves

Question 37

What nerve does the medial sural cutaneous nerve come off of?

Answer 37

Tibial nerve

Question 38

What nerve does the lateral sural cutaneous nerve come off of?

Answer 38

The common fibular nerve

Question 39

What nerve does the sural communicating branch come off of?

Answer 39

Lateral sural cutaneous nerve

Question 40

When does the medial sural cutaneous nerve become the sural nerve?

Answer 40

When it is joined by the sural communicating branch from the lateral sural cutaneous nerve.