Nerves and vessels of the lower limb Flashcards
Where do nerves to the lower limb emerge from?
Lumbosacral plexus
L2-S3
What does the femoral nerve supply?
Anterior compartment of thigh
What does the obturator nerve supply?
Medial (adductor) compartment of thigh
What does the sciatic nerve supply?
Posterior thigh
Anterior and posterior leg
Foot
Which muscle is an important landmark in relation to the nerves and vessels of the gluteal region?
Piriformis muscle- one of the lateral rotator group of gluteal muscles
What does the sciatic nerve divide into?
Tibial nerve
Common peroneal nerve
What does the tibial nerve supply?
Posterior compartment of the leg- superficial and deep calf muscles
What does the tibial nerve divide into?
Medial and lateral plantar nerves at the sole of the foot
What do the medial and lateral plantar nerves supply?
Muscles of the foot and regions of sensation in the foot
What does the common peroneal nerve divide into?
Deep and superficial peroneal nerves
What are the roots of the femoral nerve?
L2-4, posterior fibres
What are the roots of the obturator nerve?
L2-4, anterior fibres
What are the roots of the sciatic nerve?
L3-S3, anterior and posterior fibres
What are the roots of the superior gluteal nerve?
L4-S1
What are the roots of the inferior gluteal nerve?
L5-S2
What does the superior gluteal nerve supply?
Gluteus medius and minimus, tensor fascia lata
What does the inferior gluteal nerve supply?
Gluteus maximus
What is the segmental motor supply to hip flexors?
L2-3
What is the segmental motor supply to hip extensors?
L4-5
What is the segmental motor supply to knee extensors?
L3-4
What is the segmental motor supply to knee flexors?
L5-S1
What is the segmental motor supply to ankle dorsiflexors (extensors)?
L4-5
What is the segmental motor supply to ankle plantarflexors (flexors)?
S1-2
When assessing nerve function, what is seen in a root injury such as prolapsed intervertebral disc at L5/S1?
Motor- loss of eversion
Sensory- loss of sensation outer border of foot
Reflex- loss of ankle jerk (S1)
Autonomic- minimal
When assessing nerve function, what is seen in a lesion of common peroneal nerve at fibular neck?
Motor- foot drop
Sensory- dorm of foot at least
Reflex- none
Autonomic- minimal
What arteries supply the lower limb?
Abdominal aorta Common iliac arteries (internal and external) Femoral artery (deep femoral artery is main supply to thigh) Popliteal artery -Posterior tibial artery -Anterior tibial artery -Peroneal artery -Dorsalis pedis
What do the femoral artery and vein pass through from the anterior compartment to the popliteal fossa?
Hiatus of adductor magnus muscle
What are the superficial veins of the lower limb?
Dorsal venous arch Long saphenous vein Short saphenous vein Perforating veins Sapheno-femoral junction Blood flow is from superficial to deep.
What are the deep veins of the lower limb?
Run alongside arteries, venae comitantes 'Muscle pump' in the calf. Anterior and posterior tibial veins Popliteal vein (receives SSV) Profunda femoris vein Femoral vein (receives LSV) External iliac vein
When may cut-down of the LSV at medial malleolus be required?
To administer fluids in a shocked patient, ATLS
2cm lateral and proximal to medial malleolus
What happens in arterial embolism?
Sudden occlusion
Acute ischaemia
Intermittent claudication (muscle pain commonly in calf during activity, associated with arterial disease)
What is compartment syndrome?
The neuromuscular compartments of the limbs are enclosed in fibrous sheaths which confines them
Ischaemia caused by trauma-induced increased pressure in a confined limb compartment
Commonly the anterior, posterior and lateral compartments of the leg
What is required in acute compartment syndrome (trauma-associated)?
Emergency fasciotomy to prevent death of muscles in the affected compartment
How do varicose veins occur?
Perforating veins connecting superficial and deep veins contain a valve that allows flow only from superficial to deep.
If the valve is compromised, blood is pushed from deep to superficial veins, leading to varicose veins.
Why is the muscle pump in the calf important?
In the leg, deep vessels are sandwiched between layers of calf muscles.
During walking and running, contractions of these muscles squeeze the thin-walled veins and push blood up them.
Immobility means less efficient venous return from the foot and leg
Sluggish deep venous return can lead to deep vein thrombosis.
What is the purpose of elastic surgical socks?
Compress superficial veins, promoting more vigorous deep venous return to prevent DVT.
