Lower Limb 2: Posterior Thigh and Popliteal Fossa

Question 1

Where would you find the medial and lateral linea aspera?

Answer 1

Posterior, superior 2/3 of the shaft of the femur

Question 2

Which is more superior, the epicondyle or the condyle?

Answer 2

The epicondyle

Question 3

Function of the fascia lata?

Answer 3

forms 3 intermuscular septa, separating the thigh into 3 compartments:
anterior extensor (of the leg at the knee)
posterior flexor (flex leg at knee and extend thigh at hip)
medial adductor (thigh at hip)

Question 4

What are the muscles of the posterior compartment of the thigh? (Hamstrings)

Answer 4

Semimembranosus
Semitendinosus
Biceps Femoris (long head)
(Hamstring part of adductor magnus muscle)

Question 5

What is the common origin of the hamstrings?

Answer 5

Ischial tuberosity

Question 6

What is the innervation of the hamstrings?

Answer 6

Sciatic nerve, tibial division

L5, S1, S2

Question 7

Where does Semimembranosus insert?

Answer 7

Groove and adjacent bone on posterior surface of medial tibial condyle

Question 8

Where does Semitendinosus insert?

Answer 8

Medial surface of superior tibia

Question 9

Where does Biceps Femoris (long head) insert?

Answer 9

Head of fibula

Question 10

Why is Biceps Femoris (short head) not considered to be part of the hamstrings?

Answer 10

Does not share common origin or innervation

Origin: lateral linea aspera, lateral supracondylar ridge of femur
Insertion: head of fibula
Innervation: Sciatic nerve, Common Peroneal divison (L4-S2)

Question 11

What are the functions of the hamstrings?

Answer 11

Flex leg at knee
Extend thigh at hip
Biceps femoris rotates laterally
Semi’s rotate medially

Question 12

Why is part of adductor magnus considered to be one of the hamstrings?

Answer 12

Shares the same common origin (ischial tuberosity) and nerve supply of the hamstrings (sciatic nerve, tibial division L5, S1, S2)

Question 13

Describe the dual innervation of the adductor magnus muscle

Answer 13

Adductor part - Obturator nerve (L2, L3, L4)

Hamstring part - Sciatic nerve, tibial division (L5, S1, S2)

Question 14

describe the blood supply of the hamstrings

Answer 14

upper part: inferior gluteal artery
Middle (main part): profunda femoris artery and its penetrating branches
Lower part: Popliteal artery

Question 15

describe the course of the sciatic nerve through the thigh

Answer 15

Descends into the hamstrings, where it divides at a variable point in the leg
Splits into the Tibial division and the common fibular (peroneal) nerve
Common fibular deviates laterally, both enter the popliteal fossa

Question 16

What forms the floor and roof of the popliteal fossa?

Answer 16

Floor - popliteal surface of femur

• capsule of the knee joint and oblique popliteal ligament
• strong fascia covering popliteus

Roof - skin
- superficial fascia

Question 17

What are the boundaries of the popliteal fossa?

Answer 17

Supero-lateral: biceps femoris tendon
Supero-medial: semimembranosus
Infero-medial: medial head of gastrocnemius
Infero-lateral: lateral head of gastrocnemius

Question 18

How is the posterior compartment of the leg divided?

Answer 18

Divided into a superficial and a deep compartment by the transverse intermuscular septum.

Question 19

What muscles are in the superficial compartment of the posterior leg?

Answer 19

Gastrocnemius
Soleus
Plantaris

Question 20

Which muscle of the posterior leg can act as a flexor of the knee as well as a plantarflexor of the ankle joint?

Answer 20

Gastrocnemius

Plantaris

Question 21

What does the Tibial nerve innervate?

Answer 21

Supplies all muscles in posterior thigh except short head of biceps femoris
+ supplies hamstring part of adductor magnus
supplies muscles of posterior compartment of the leg
Intrinsic muscles in the sole of the foot except first 2 dorsal interossei
Skin on posterolateral side of lower half of the leg, medial ankle, foot, little toe and skin on sole.

Question 22

What does the Common Peroneal (fibular) nerve do?

Answer 22

Innervates short head of biceps femoris in post. thigh
all muscles in anterior and lateral compartments of the leg
Extensor digitorum brevis on dorsal foot
first 2 dorsal interossei in sole of foot
skin over lateral leg and ankle + dorsal aspect of foot and toes

Question 23

What are the contents of the popliteal fossa?

Answer 23

From lateral to medial:
N - V - A
Nerve (tibial) - vein - artery