Vasculature of the Lower Limb Flashcards
What are the superior and inferior gluteal arteries branches of?
The internal iliac arteries.
What is the cruciate anastomosis?
4-way anastomosis between branches of the internal iliac, profunda femoris and circumflex femoral arteries.
Where is the cruciate anastomosis located?
In the hip, posterior to the proximal femur.
Why is the cruciate anastomosis clinically important?
Allows blood to bypass blockage of external iliac or proximal femoral arteries.
What are the main arteries of the thigh? (3)
- Femoral artery
- Profunda femoris artery
- Obturator artery
Which artery supplies the anterior compartment of the thigh?
Femoral artery.
-continuation of external iliac
What is the boundary of the femoral artery?
Inguinal ligament.
Which arteries supply the posterior compartment of the thigh?
Perforating arteries (4). -branch of profunda femoris
Which tendon do the perforating arteries pierce to enter the back of the thigh?
Adductor magnus.
Which artery supplies the medial compartment of the thigh?
Obturator artery.
-branch of internal iliac
How does the abdominal aorta give rise to the femoral arteries?
Abdominal aorta
» common iliac arteries
» internal and external iliac arteries.
Femoral artery = continuation of external iliac artery.
What happens to the femoral artery at the knee?
- Passes from the anterior compartment to enter the popliteal fossa.
- Becomes popliteal artery.
When is the popliteal artery best palpated?
When the knee is flexed.
Where is the genicular anastomosis?
At the front/side of the knee.
What is the genicular anastomosis composed of?
5 genicular branches of the popliteal arteries.
sup lat, sup med, middle, inf lat, inf med
What is the function of the genicular anastomosis?
Maintains blood supply to leg during knee flexion.
-popliteal artery may be obstructed
What are the main arteries of the leg (below knee)? (3)
- Anterior tibial artery
- Posterior tibial artery
- Fibular artery
Which artery supplies the anterior compartment of the leg?
Anterior tibial artery.
-terminal branch of popliteal artery
Which artery supplies the posterior compartment of the leg?
Posterior tibial artery.
-terminal branch of popliteal artery
Which artery supplies the lateral compartment of the leg?
Fibular artery.
-branch of post tibial artery
Which arteries are terminal branch of the popliteal artery? (2)
Posterior and anterior tibial arteries.
What are the main arteries in the foot? (2)
-Dorsalis pedis artery
-Med & lat plantar arteries
(-Deep plantar arch)
Which artery supplies the dorsal aspect of the foot?
Dorsalis pedis artery.
-continuation of ant tibial artery
Which arteries supply the plantar aspect of the foot(sole)?
Medial and lateral planter arteries.
-bifurcation of posterior tibial artery
What is the (deep) plantar arch composed of?
Anastomosis of deep plantar branch of dorsalis pedis artery and lateral plantar artery.
What proportion of the population have a superficial plantar arch?
5%.
What does the posterior tibial artery bifurcate into?
Medial and lateral plantar arteries.
Which arteries are often palpated? (4)
- Femoral artery
- Popliteal artery
- Posterior tibial artery
- Dorsalis pedis artery
Where is the femoral artery palpated?
In the groin.
-generally superficial and easy to palpate
Where is the popliteal artery palpated?
Deep in the popliteal fossa, against the femur.
-best when knee flexed
Where is the posterior tibial artery palpated?
Behind malleolus (ankle). -medial prominence of lower tibia
Where is the dorsalis pedis artery palpated?
Imaginary line proximally from 1st and 2nd toes.
Why is the femoral artery vulnerable to injury?
Superficial in the femoral triangle.
Why is the femoral artery clinically important?
Important access point; catheter inserted»_space; target organ.
-minimally invasive procedures (e.g. coronary angiogram, embolisation of berry aneurysm)
What is peripheral vascular disease?
Narrowed arteries»_space; reduced blood flow to limbs.
-can occur in pelvis/lower limbs
What are the main causes of narrowed arteries in the lower limbs?
- Atherosclerosis
- Occlusion (thrombus/embolus)
What causes acute ischaemia? (3)
- Acute occlusion (e.g. thrombus)
- Trauma
- Compartment syndrome
How does acute ischaemia present?
6 P’s.
- pain
- pallor
- perishingly cold
- pulseless
- paraesthesia
- paralysis
How is acute ischaemia treated?
medical emergency
Depending on cause;
- Revascularisation (prevent irreversible damage)
- Imaging (show occlusion)
- Graft (from common femoral to popliteal)
Where do atherosclerotic changes often occur?
Lower femoral artery.
How does chronic ischaemia develop?
Asymptomatic
»Intermittent claudication
»Rest/night pain
»Tissue loss/ulceration/gangrene
What is intermittent claudication?
Cramping pain in the leg due to blockage of femoral artery.
Why are the symptoms of acute ischaemia less marked in someone already suffering from chronic ischaemia?
Collateral circulation is better developed.
What are the superficial veins of the lower limb? (2)
Great and short saphenous veins.
Where do the saphenous veins lie?
In subcutaneous tissue, superficial to deep fascia.
Where do the saphenous veins drain?
Into deep veins.
-femoral and popliteal veins.
Where is the great saphenous vein located?
Medial leg.
-anterior to medial mallelous
What are the deep veins of the lower limb?
- Ant/post TIBIAL veins and ant/post FIBULAR veins.
- Join»_space; POPLITEAL vein.
- Becomes FEMORAL vein.
What type of vessels are the tibial and fibular veins?
Venae comitantes.
-accompany the major arteries
What is the function of perforating veins?
Drain blood from superficial veins to deep veins.
What is venous return from deeps veins aided by? (2)
- Muscular contraction (‘pump’)
- Deep fascia (‘compression stocking’)
What do incompetent valves lead to?
Varicose veins.
Which veins can be used for emergency IV access? (2)
- Femoral vein
- Great saphenous vein
What can the femoral vein be used for?
- Temporary access (e.g. trauma, burns)
- Venepuncture (emergency)
NB. ideally use internal jugular/subclavian veins
What is the great saphenous vein used for?
Emergency IV access.
-lies immediately ant to medial mallelous
What causes varicose veins?
Increased pressure in saphenous veins due to proximal obstruction (e.g. pregnancy).
What can happen when veins become dilated (varicose veins)?
Blood may stagnate in skin»_space; breakdown and ulceration.
What are complication of varicose veins? (3)
- Bleeding
- Superficial thrombophlebitis
- Venous ulcers (med ankle)
What are the main risk factors for DVT?
- Immobility
- Surgery
- Malignancy
- Pregnancy
- Sepsis
What proportion of untreated DVT leads to mortality due to PE?
1-2%.
What is the main network of nerves in the lower limb?
Lumbosacral plexus.
-lumbar plexus and sacral plexus
What is the lumbar plexus formed from?
Anterior rami of L1-4.
What is the sacral plexus formed from?
Anterior rami of L4-S5.
What is the sacral plexus joined by?
Lumbosacral trunk.
-branch of L4 anterior rami that joins L5
Which nerves does the lumbar plexus give rise to? (2)
- Obturator nerve (L2-4)
- Femoral nerve (L2-4)
Which spinal cord levels is the obturator nerve composed of?
L2-4.
Which spinal cord levels is the femoral nerve composed of?
L2-4.
Which nerves does the sacral plexus give rise to? (3)
- Sciatic nerve (L4-S3)
- Superior gluteal nerve (L4-S1)
- Inferior gluteal nerve (L5-S2)
Which spinal cord levels is the sciatic nerve composed of?
L4-S3.
Which spinal cord levels are the gluteal nerves composed of?
Superior: L4-S1
Inferior: L5-S1
Where are the lumbar and sacral plexuses located?
Deep within pelvis and abdomen.
What does the femoral nerve supply?
Anterior compartment of the thigh.
How does the femoral nerve enter the thigh?
Passes under the inguinal ligament.
What is the terminal branch of the femoral nerve?
Saphenous nerve.
What does the saphenous nerve supply?
Skin of medial leg.
-passes through adductor hiatus
Which nerve supplies the medial compartment of the thigh?
Obturator nerve.
What does the obturator nerve divide into?
Anterior and posterior branches.
-lie on either side of adductor brevis
What does the sciatic nerve supply?
- Posterior thigh
- All of leg and foot
Which 2 nerves is the sciatic nerve composed of?
- Tibial nerve
- Common fibular nerve
What is the tibial nerve composed of?
Anterior divisions of anterior rami.
What is the common fibular nerve composed of?
Posterior divisions of anterior rami.
Where does the sciatic nerve normally bifurcate?
Distal thigh.
-pelvis in 12%
What is another name for the common fibular nerve?
Common perineal nerve.
How is the sciatic nerve injured?
- During intramuscular injections
- Hip injuries/dislocations
Where must intramuscular injection be performed?
Superolateral quadrant.
What does the common fibular nerve bifurcate into?
Superficial and deep branches.
What does the superficial branch of the common fibular nerve supply?
Lateral compartment of the leg.
What does the deep branch of the common fibular nerve supply?
Anterior compartment of the leg.
Where in the common fibular nerve vulnerable?
As it winds around the neck of the fibula.
What does injury to the common fibular nerve lead to?
Paralysis of dorsiflexor muscles.
|»_space;foot drop and altered gait
Which nerve supplies the posterior compartment of the leg?
Tibial nerve.
Where does the tibial nerve bifurcate?
Deep to the flexor retinaculum.
What does the tibial nerve birfurcate into?
Medial and lateral plantar nerves.
What does the medial plantar nerve supply?
- 4 muscles
- Skin to med 3 1/2 digits
What does the lateral plantar nerve supply?
- All other plantar muscles
- Skin to lat 1 1/2 digits
