Lecture 4: Neurovasculature of the Lower Limb Flashcards
From where do the superior and inferior gluteal arteries branch?
Internal iliac
What is the clinical importance of the anastomosis between branches of the internal iliac and profunda femoris arteries (cruciate anastomosis).
Allows blood to bypass a blockage of the external iliac or proximal femoral arteries.
e.g. superior gluteal artery anastamoses with inferior gluteal artery
Where does the femoral artery begin?
Inguinal ligament - a continuation of the external iliac
What is the obdurator artery a branch of?
Branch of the internal iliac
What are the important arteries of the thigh?
Anterior compartment
- Femoral artery
- Continuation of external iliac
- Boundary - inguinal ligament
Posterior compartment
- Perforating arteries (4)
- profunda femoris artery
Medial compartment
- Obturator artery
- A branch of the internal iliac
What happens to the femoral artery at the knee?
- The femoral artery passes from the anterior compartment to enter the popliteal fossa
- Here it is named the popliteal artery
Pulsation can best be felt when the knee is flexed
What is the genicular anastamosis?
Maintains blood supply to the leg during knee flexion which may impinge the popliteal artery.
What are the branches of the genicular anastamosis?
- Superior lateral
- Superior medial
- Middle
- Inferior lateral
- Inferior medial
What are the main arteries of the leg?
Anterior compartment
- Anterior tibial artery
- Terminal branch of popliteal artery
Posterior compartment
- Posterior tibial artery
- Terminal branch of popliteal artery
Lateral compartment
- Fibular artery
- Branch of posterior tibial artery
What are the main arteries of the foot?
Dorsal aspect
- Dorsalis pedis artery
- Continuation of anterior tibial artery
Plantar aspect
- Medial and lateral plantar arteries
- Bifurcation of posterior tibial artery
What are the 6 Ps and what is their relevance?
Pain Pallor Perishingly cold Pulseless Paraesthesia Paralysis
Signs and symptoms of the acutely ischemic leg.
What is peripheral vascular disease?
- The arteries of the pelvis and lower limbs are affected by the same disease processes as other arteries (coronary, cerebral) = atherosclerosis
- The lower limb arteries can become occluded by embolus or thrombus
- Acute ischaemia – usually acute occlusion by thrombus or emboli; can also be caused by trauma or compartment syndrome
What are the possible presentations of chronic ischaemia?
- Asymptomatic
- Intermittent claudication – mild
- Intermittent claudication - severe
- Rest pain / night pain
- Tissue loss / ulceration / gangrene
What are the superficial veins of the lower limb?
- Great and short saphenous veins.
- Lie in subcutaneous tissue, superficial to deep fascia
- Drain into deep veins (femoral and popliteal)
What are the features of the deeps veins of the lower limb?
- Accompany the major arteries
- Anterior and posterior tibial veins and the fibular veins are actually venae comitantes.
- These joint to form the popliteal vein which in turn becomes the femoral vein.
What is the function of the perforating veins?
- Drain blood from the superficial veins to the deep veins
- Contain valves to prevent backflow
- Venous return from deep venous aided by
muscular contraction - ‘muscle pump’
deep fascia - ‘compression stocking’
What is the clinical importance of the femoral vein?
Temporary access:
- Trauma
- Burns
- Otherwise very difficult access (shock, IVDU, thrombosed peripheral veins, obesity)
What is the clinical importance of the great saphenous vein
- Lies immediately in-front of the medial malleolus
- Site can be used in emergencies to obtain IV access
Why might varicose veins ulcerate?
The veins become dilated and incompetent
Blood then may stagnate in the skin – leading to breakdown and ulceration
From what branches is the lumbar plexus formed?
Anterior rami of L1-L4
From what branches is the sacral plexus formed?
Anterior rami of L4-S5
What joins the sacral plexus?
Lumbosacral trunk - branch of L4 anterior ramus that joins L5.
What does the lumbar plexus give rise to?
- Obturator nerve (L2-L4)
- Femoral nerve (L2-L4)
What does the sacral plexus give rise to?
- Sciatic nerve (L4-S3)
- Superior (L4-S1) and inferior (L5-S2) gluteal nerves
What are the features of the femoral nerve?
- Supplies anterior compartment of thigh
- Passes under inguinal ligament to enter thigh
- Terminal branch is saphenous nerve which passes through adductor hiatus to supply skin of medial leg
What are the features of the obturator nerve?
- Supplies medial compartment of thigh
- Divides into anterior and posterior branches that lie on either side of adductor brevis
What are the features of the sciatic nerve?
- Supplies posterior thigh and all of the leg and foot
- Really composed of 2 nerves: Tibial nerve (anterior divisions of anterior rami) and Common fibular nerve (posterior divisions of anterior rami)
- Usually bifurcates in distal thigh, however, already separate as leave the pelvis in 12% population
What are the features of the common fibular (peroneal) nerve?
- bifurcates into superficial and deep branches
- duperficial branch supplies lateral compartment of the leg
- deep fibular supplies anterior compartment of the leg
- vulnerable as it winds round the neck of the fibula
What would be the consequence of injury to the common fibular/peroneal nerve
Paralysis of dorsiflexor muscles resulting in ‘foot-drop’ and altered gait
What is supplied by the tibial nerve?
- Supplies posterior compartment of the leg
- Bifurcates deep to the flexor retinaculum into medial and lateral plantar nerves.
What is the medial plantar nerve?
Smaller than lateral – only supplies 4 muscles but supplies skin to posteromedial 3 ½ digits
What is the lateral plantar nerve?
Supplies all other plantar muscles and skin to posterolateral 1 ½ digits
Which myotomes are responsible for lateral external rotation of the hip?
L1 and L5
Which myotomes are responsible for medial internal rotation of the hip?
L1, L2, L3
Which myotomes are responsible for abduction of the hip?
L5 and S1
Which myotomes are responsible for adduction of the hip?
L1, L2, L3 & L4
Which myotomes are responsible for inversion of the foot?
L4 and L5
Which myotomes are responsible for eversion of the foot?
L5 and S1
Which myotomes are responsible for dorsiflexion of the FOOT?
L5 and S1
Which myotomes are responsible for plantarflexion of the foot AND ankle?
S1 and S2
Which myotomes are responsible for the dorsiflexion of the ANKLE?
L4 and L5
Which myotomes are responsible for extension of the hip?
L4 and L5
Which myotomes are responsible for flexion of the hip?
L2 and L3
Which myotomes are responsible for flexion of the knee?
L5 and S1
Which myotomes are responsible for extension of the knee?
L3 and L4
