A7 - Lower limb bones & NV supply

Question 1

What arteries are at risk of damage with fractures of the femur?

Answer 1

Medial and lateral circumflex arteries

Question 2

Which artery contributes to vascular anastomoses around the knee joint?

Answer 2

Descending genicular arteries

Question 3

What bones contribute to the medial longitudinal arch of the foot?

Answer 3

Calcaneus, talus, navicular, 3 cuneiforms and the first 3 metatarsals

Question 4

What bones contribute to the lateral longitudinal arch of the foot?

Answer 4

Calcaneus, cuboid, 4th and 5th metatarsals

Question 5

Describe the course of the femoral artery

Answer 5

1- External iliac becomes the femoral artery when it enters the femoral triangle by passing under the inguinal ligament
2- Gives off profunda femoris branch within the femoral triangle
3- Passes through the adductor canal under the sartorius
4- Passes through adductor hiatus
5- Enters popliteal fossa and becomes the popliteal artery

Question 6

What are the branches of the femoral artery?

Answer 6

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Descending genicular arteries
Profunda femoris artery (deep femoral)
Superficial epigastric
Superficial circumflex iliac artery
Superficial external pudendal artery
Deep external pudendal arteries

Question 7

What are the branches of the popltieal artery?

Answer 7

Anterior tibial
Posterior tibial
Fibular artery (may come off posterior tibial in some people)

Question 8

What arteries supply the anterior, posterior and lateral compartments of the leg?

Answer 8

Anterior = anterior tibial
Posterior = posterior tibial
Lateral = fibular artery

Question 9

What are the 2 main superficial veins of the leg? What side of the leg are they found and where do they drain into?

Answer 9

Great saphenous vein = MEDIAL
- Drains into femoral vein

Short saphenous vein = LATERAL
- Drains into popliteal vein

Question 10

What does the anterior tibial artery eventually become?

Answer 10

Dorsalis pedis artery

Question 11

What does the posterior tibial artery eventually become?

Answer 11

Medial and lateral plantar arteries (bottom of foot)

Question 12

Which bone forms the heel of the foot?

Answer 12

Calcaneus

Question 13

What articulates at the proximal tibiofibular joint?

Answer 13

Head of fibular articulates with the lateral condyle of the tibia (tibial ‘plateau surface’)

Question 14

What type joint is the proximal tibiofibular joint?

Answer 14

Plane type synovial joint

Question 15

What articulates at the distal tibiofibular joint?

Answer 15

Fibular articulates with the fibular notch of the tibia

Question 16

What articulates at the ankle joint?

Answer 16

1: Distal end of tibia with trochlear of talus
2: Medial malleolus of tibia with medial surface of talus
3: Lateral malleolus of fibular with lateral aspect of talus

Question 17

What are the bones of the foot?

Answer 17

7 tarsal bones: calcaneus, navicular, talus, cuboid, 3 cuneiforms (medial, intermediate, lateral)
5 metatarsals: 1= big toe, 5 = little toe
3 phalanges for each toe, except the big toe (2)

Question 18

Which bone of the foot is at highest risk of avascular necrosis and why?

Answer 18

Talus - as no muscles attach here

Question 19

Which tarsal bones of the foot are in the proximal and distal rows?

Answer 19

Proximal = calcaneus, navicular, talus
Distal = cuboid, 3 cuneiforms - medial, intermediate and lateral

Question 20

What bones contribute to the transverse arch of the foot?

Answer 20

Metatarsal bones, cuboid and 3 cuneiform bones

Question 21

What is pes cavus?

Answer 21

Unusually high medial longitudinal arch, impairs the ability to shock absorb while walking = increased stress on ball and heel of foot

Question 22

What is pes planus?

Answer 22

Longitudinal arches have been lost, may cause few symptoms or can cause pain in children, aching in adults

Question 23

What branches does the deep femoral (profunda femoris) artery give off?

Answer 23

‘Let Me Pass’
- Lateral circumflex femoral artery
- Medial circumflex femoral artery
- Perforating branches

Question 24

What artery supplies the medial compartment of the thigh and where is it derived?

Answer 24

Obturator artery
From the internal iliac artery

Question 25

What forms the deep plantar arch? What does it supply?

Answer 25

Dorsalis pedis
Lateral plantar artery
= Deep plantar arch supplies the toes

Question 26

What are the 3 main nerves of the lower limb and where do they arise?

Answer 26

Sciatic = L4-S3
Femoral = L2-L4
Obturator = L2-L4

Question 27

What are the branches of the sciatic nerve and where do they supply?

Answer 27

Divides into common fibular (peroneal) and posterior tibial nerves. Common fibular divides into superficial and deep peroneal nerves:
- Posterior tibial = posterior compartment of leg
- Superficial peroneal = lateral compartment of leg
- Deep peroneal = anterior compartment of leg

Question 28

What nerve if damaged would cause foot drop?

Answer 28

Common fibular nerve

Question 29

Where does the obturator nerve provide motor and sensory innervation?

Answer 29

Motor: medial muscles of thigh, except hamstring portion of adductor magnus
Sensory: skin over proximal part of medial thigh

Question 30

Where does the femoral nerve provide motor and sensory innervation?

Answer 30

Motor: anterior muscles of thigh
Sensory: supplies cutaneous branches to anteromedial thigh and medial side of leg and foot

Question 31

Where does the sciatic nerve provide motor and sensory innervation?

Answer 31

Motor: posterior muscles of thigh
Sensory: lateral leg and foot via terminal branches

Question 32

Where would a patient lose feeling if they lost S3 and S4 sensory innervation?

Answer 32

condition called ‘saddle anaesthesia’ = patient experiences urinary incontinence and loses all feeling in that area, i.e. cannot feel when they wipe

Question 33

How can you tell if a femur is a L or R one?

Answer 33

Head inserts medially, then from the top to bottom it should angle inwards
Also has linear aspera (thick ridge) on posterior surface

Question 34

Where is the quadrate tubercle found?

Answer 34

On the intertrochanteric crest of the femur

Question 35

How can you tell if the tibia is a L or R one?

Answer 35

Inferior end has medial malleolus
Superior end has ‘tibial tuberosity’ - prominent bulge on anterior side

Question 36

What is found between the medial and laeral condyles of the tibia?

Answer 36

Intercondylar tubercles (/ eminence) = bumpy

Question 37

How can you tell if the fibular is a L or R one?

Answer 37

Hold it by its head (thicker end) in your right hand, then position the lateral malleolus so it is facing laterally - if the malleolar fossa (indentation on distal end) is facing towards you = R one, if away from you = L

Question 38

How can you orientate a patella?

Answer 38

Has an apex that points down, then the anterior surface is rough, and the posterior surface is smooth