Neurovasculature of the lower limb Flashcards
What are the superior and inferior gluteal arteries branches of?
internal iliac arteries
What are the arteries of the gluteal region? (in order of course) (9)
- superior gluteal
- inferior gluteal
- medial femoral circumflex
- lateral femoral circumflex artery
- deep artery of the thigh
- first perforating artery
- femoral artery
- second perforating artery
- third perforating artery
What do the arteries around the hip also known as?
cruciate anastomosis
Which branches does the cruciate anastomosis involve?
branches of internal iliac and profunda femurs arteries
Why is the cruciate anastomosis clinically important?
allows blood to bypass a blockage of the external iliac or proximal femoral arteries
= allows collateral supply
What is the artery that supplies the anterior compartment of the thigh, what is it a continuation of and what is it’s boundary?
femoral artery
continuation of external iliac artery
boundary - inguinal ligament
What are the arteries that supply the posterior compartment of the thigh?
4 perforating arteries
profunda femoris artery
What artery supplies the medial compartment of the thigh and what is it a branch of?
obturator artery
internal iliac artery
What is the femoral artery called when it enters the popliteal fossa from the anterior compartment of the thigh?
popliteal artery
When can pulsation of the popliteal artery be felt?
when knee is flexed
What does the genicular anastomosis allow?
maintenance of blood supply to the leg during knee flexion
as knee flexion may impinge the popliteal artery
What is the artery of the anterior compartment of the leg and where is it derived from?
anterior tibial artery
terminal branch of popliteal artery
What is the artery of the posterior compartment of the leg and where is it derived from?
posterior tibial artery
terminal branch of popliteal artery
What is the artery of the lateral compartment of the leg?
fibular artery
branch of posterior tibial artery
Where does the femoral artery go through to get to the popliteal fossa to become the popliteal artery?
adductor hiatus
What are the arteries of the dorsal aspect of the foot (top of foot) and what is it a continuation of?
dorsalis pedis artery
continuation of anterior tibial artery
What are the arteries of the plantar aspect of the foot (sole of the foot) and where are they derived from?
medial and lateral plantar arteries
bifurcation of posterior tibia artery
What is the deep plantar arch?
anastomosis of the deep plantar branch of the dorsal is pedis artery with lateral plantar artery
What plantar arch is present in only 5% of the population?
superficial plantar arch
What is important to do in palpation of lower limb arteries (pulses)?
compare left and right limbs
What arteries do you palpate (pulses) in the lower limb? (4)
- femoral - relatively superficial in groin
- popliteal - leg in flexion to open up pop fossa and compress it
- posterior tibial - behind medial malleolus of the ankle
- dorsalis pedis - anterior aspect of foot over dorsum - gap between 1st and 2nd toes
Where is the femoral artery in the femoral triangle?
quite superficial
As the femoral artery is quite superficial in the femoral triangle what is it vulnerable to?
injury and laceration
The femoral artery is easily accessible in people for what?
for ABG in emergencies if poor peripheral perfusion/pulses
for minimally invasive procedures (catheters):
- coronary angioplasty
- coronary angiography
- embolisation of berry aneurysm
What temporary problems can minimal invasive procedures cause?
- false aneurysms
- big haematomas
- bleeding
What is peripheral vascular disease (PVD)?
- arteries of the pelvis and lower limbs affected by atheroscelorosis
What can happen in peripheral vascular disease?
the lower limb arteries can become occluded by embolus or thrombus
What is acute ischaemia caused by?
acute occlusion by thrombus or emboli
usually by trauma or compartment syndrome
How worrying is acute ischaemia of the limb?
a medical emergency
requires urgent revascularisation
What is the presentation of acute ischaemic leg? (6Ps)
- pain - due to anaerobic reps of cells - build up of lactic acid
- pallor
- perishingly cold
- pulseless
- paraesthesia
- paralysis
What is the treatment for acute ischaemic leg?
- revascularisation to prevent tissue loss
- imaging will show site of occlusion
- graft from the common femoral to popliteal bypasses the occluded vessel
In acute ischaemia of the leg what do atheroscelorotic changes often affect which artery?
lower femoral artery
How does the body try to compensate for the acute ischaemic limb?
collateral circulation via anastomoses between branches of profunda femoris and popliteal
What are the symptoms of chronic ischaemia?
- assymptomatic
- mild intermittent claudication
- severe intermittent claudication
- rest pain/ night pain
- tissue loss/ ulceration/ gangrene
Why might the symptoms and signs of acute ischaemia be less marked in someone already affected by chronic ischaemia?
onset is slow
may not have much changes with 6 Ps
What is claudication?
pain when walking
What are the superficial veins of the lower limb?
- great saphenous veins
2. short saphenous vein
Where do the superficial veins lie?
subcutaneous tissue
superficial to deep fascia
What do the superficial veins drain into?
deep veins
femoral and popliteal
What are the major arteries accompanied by?
deep veins of the limb
What veins are venae commitantes (or accompanying veins)?
anterior and posterior tibial veins
fibular veins
What do the venae commitantes (anterior and posterior tibial veins, fibular veins) join to to become the femoral vein?
popliteal vein
What are perforating veins?
drain blood from the superficial veins into the deep veins?
What do perforating veins contain to prevent the back flow of blood?
valves
What is venous return aided by?
muscular contraction - muscle pump
deep fascia - compression stocking
What can the femoral vein be used for in an emergency?
emergency IV access
When can the femoral vein be temporarily accessed?
- trauma
- burns
- people with difficult access - obesity, shock, IVDU, thromboses peripheral veins
- venepuncture in emergencies
Where does the great saphenous vein lie immediately in front of and what can this site be used for?
medial malleolus
obtain IV access
What are varicose veins?
increased pressure in spahenous veins that can be caused by proximal venous obstruction - pregnancy or pelvic tumour
What happens in varicose veins?
veins become dilated and incompetent
blood then may stagnate in the skin - leading to breakdown and ulceration
What are the complication so varicose veins?
- bleeding
- superficial thrombophelbitis
- venous/varicose ulcers - medial side of the ankle, dermatitis and skin thickening
What is deep vein thrombosis?
abnormal clotting in the pelvis or legs
What can happen to the clots in a DVT?
clots can break off an travel to the lungs - PE
What happens if the DVT remains untreated?
1-2% mortality from PE
What do 50% of patients with DVT have?
pain and swelling in affected leg
What are the risk factors for DVT? (7)
- previous VTE
- immobility
- recent surgery
- malignancy
- pregnancy
- IV drug use
- sepsis
What is the lumbar plexus formed from?
anterior rami L1-L4
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 rams that joins L5
What nerves does the lumbar plexus give rise to?
obturator nerve - L2-L4
femoral nerve - L2-L4
What nerves does the sacral plexus give rise to?
sciatic nerve - L4-S3
superior gluteal nerve L4-S1
Inferior gluteal nerve L5-S2
Why are the nerves of the lumbar and sacral plexus rarely damaged?
because they are deep within pelvis and abdomen
What does the femoral nerve supply?
anterior compartment of the thigh
What does the femoral nerve pass under to enter the thigh?
inguinal ligament
What is the terminal branch of the femoral nerve and what doe sit pass through and what doe sit supply?
saphenous nerve
adductor hiatus
lies more lateral
What does the obturator nerve supply?
medial compartment of the thigh
What does the obturator nerve divide into and where do these divisions lie?
anterior and posterior branches
lie either side of the adductor brevis
What does the sciatic nerve supply?
posterior thigh and all of the leg and foot
What is the sciatic nerve composed of?
tibial nerve - anteiror divisions of the anterior rami
Common fibular nerve - posterior division of the anterior rami
Where does the sciatic nerve usually bifurcate?
in distal thigh
When is the sciatic nerve at risk of injury? (2)
intramuscular injections
hip injuries and dislocations
Where should intramuscular injections be performed?
superolateral quadrant - gluteal maximus
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 fibular branch of the common fibular nerve supply
anterior compartment of the leg
Why is the common fibular vein vulnerable?
as it winds around the neck of the fibula
What happens in an injured common fibular nerve?
paralysis of dorsiflexor muscles
resulting in foot drop and altered gait
What does the tibial nerve supply?
posterior compartment of the leg
Where does the tibial nerve bifurcate and what does it bifurcate into?
where - deep to the flexor retinaculum
what - medial and lateral plantar nerve
How big is the medial plantar nerve in comparison to the lateral plantar nerve?
it is smaller
What muscles and digits does the medial plantar nerve supply?
4 muscles
skin to medial 3 1/2 digits
What does the lateral plantar nerve supply?
all other plantar muscles
skin to lateral 1 1/2 digits
NOTE
learn dermatomes
Myotomes
What nerve root is involved in lateral external rotation of the hip?
L5,L1
Myotomes
What nerve roots are involved in medial internal rotation of the hip?
L1,L2 and L3
Myotomes
What nerve roots are involved in adduction of the hip?
L1,L2,L3 and L4
Myotomes
What nerve roots are involved in abduction of the hip?
L5 and S1
Myotomes
What nerve roots are involved in subtalar inversion?
L4 and L5
Myotomes
What nerve roots are involved in subtalar eversion?
L5 and S1
Myotomes
What nerve roots are involved in dorsiflexion of the toes?
L5 and S1
Myotomes
What nerve roots are involved in plantar flexion of the toes?
S1 and S2
Myotomes
What nerve roots are involved in extension of the hip?
L4 and L5
Myotomes
What nerve roots are involved in flexion of the hip?
L2 and L3
Myotomes
What nerve roots are involved in flexion of the knee?
L5 and S1
Myotomes
What nerve roots are involved in extension of the knee?
L3 and L4
Myotomes
What nerve roots are involved in dorsiflexion of the ankle?
L4 and L5
Myotomes
What nerve roots are involved in plantar flexion of the ankle?
S1 and S2