Lower Limb 2 Flashcards
What is a nerve plexus?
Formed when peripheral spinal nerve roots merge and split to produce a network of nerves
What nerves emerge from a nerve plexus?
Multisegmental peripheral nerves
What plexus supplies the lower limb?
Lumbosacral plexus
What are the 3 nerves that emerge from the lumbar plexus?
Lateral cutaneous nerve of the thigh
Femoral nerve
Obturator nerve
What trunk comes out of the lumbar plexus?
Lumbosacral trunk
What are the 4 main nerves that come out of the sacral plexus?
Superior gluteal nerve
Inferior gluteal nerve
Sciatic nerve
Posterior cutaneous nerve of the thigh
What spinal nerves make up the lumbosacral plexus?
L2-5, S1-3
What nerve supplies the anterior compartment of the thigh?
Femoral nerve
What spinal nerves is the femoral nerve made of?
L2, 3, 4
What nerve supplies the medial compartment of the thigh?
Obturator nerve
What spinal nerves is the obturator nerve made of?
L2, 3, 4
What nerve supplies the posterior thigh, anterior/posterior leg and the foot?
Sciatic nerve
What spinal nerves if the sciatic nerve made of?
L4, 5, S1, 2, 3
What is the terminal branch of the femoral nerve?
Saphenous nerve
What does the saphenous nerve supply?
Antero medial leg
Medial foot
What nerve supplies the adductor muscles in the thigh?
The obturator nerve
What muscle is a landmark for nerves passing from the buttock to the interior pelvis?
Piriformis
Where does the superior gluteal nerve enter the buttock?
Superior to the piriformis
What muscles does the superior gluteal nerve innervate?
Gluteus medius
Gluteus minimus
Tensor fasciae latae
Where does the inferior gluteal nerve enter the buttock?
Inferior to the piriformis
What muscles does the inferior gluteal nerve innervate?
Gluteus maximus
Where does the sciatic nerve enter the buttock?
Inferior to the piriformis
Where does the superior posterior cutaneous nerve of the thigh enter the buttock?
Inferior to the piriformis
In relation to the gluteus maximus, where does the sciatic nerve run?
Deep to it
In the posterior leg, what does the sciatic nerve split into?
Common peroneal nerve
Tibial nerve
What does the common peroneal nerve bifurcate into?
Superficial peroneal nerve and deep peroneal nerve
What does the superficial peroneal nerve supply?
Lateral muscles, skin of dorsum of foot
What does the deep peroneal nerve supply?
Anterior muscles and skin of cleft between 1st and 2nd toes
Where is the common peroneal nerve most susceptible to injury?
Below the knee where it comes around to the anterior leg
What muscles does the tibial nerve supply?
Superficial and deep muscle compartments of the posterior leg
How does the tibial nerve enter the foot?
At the ankle it passes posteriorly to the medial malleolus
What are the terminal branches of the tibial nerve?
Lateral and medial plantar nerves
What is a useful acronym for remembering the dermatomes of the anterior leg?
L3 to the knee
L4 to the floor
What are autonomous zones?
Regions of non overlapping sensory supply from an individual spinal root
What are the main arteries that supply the lower limb?
Iliac arteries
What blood vessel bifurcates to form the left and right common iliac arteries?
Abdominal aorta
What does the internal iliac artery supply?
Lateral thigh and buttock
What does the external iliac artery supply?
The lower limb apart from the lateral thigh and buttock
What does the external iliac artery go under when passing from the pelvis into the thigh?
Inguinal ligament
What does the external iliac artery become as it descends?
Femoral artery
What does the femoral artery become as it descends?
Popliteal artery
Where does the popliteal artery run?
The posterior leg
What is the main artery of the thigh? Where does it come from?
Deep femoral artery, is a branch of the femoral artery
What does the femoral artery pass through before entering the posterior leg as the popliteal artery?
The hiatus of the adductor magnus muscle
Where can the femoral pulse be palpated?
On the anterior thigh at the most proximal point in the thigh in the middle
What are the arteries that supply the femur?
Lateral and medial circumflex arteries
Acetabular branch of the obturator artery
Which artery supplying the head of the femur is more important in children and why?
Acetabular branch of the obturator artery as their bones are still growing
Why are the arteries supplying the femur important in terms of fracture?
Damage to the bloody supply can cause avascular necrosis of the femoral head
What does the popliteal artery become as it descends?
Tibial artery
What branches arise from the popliteal artery to supply the knee?
Genicular branches
What does the tibial artery become as it descends?
Posterior tibial artery
Anterior tibial artery
What branches off the posterior tibial artery?
Peroneal artery
What does the posterior tibial artery become as it enters the foot?
Medial plantar artery
Lateral plantar artery
What arteries supply the posterior and lateral aspects of the leg?
Posterior tibial artery
Peritoneal artery
What does the anterior tibial artery run along?
Interosseous membrane
What does the anterior tibial artery become as it enters the foot?
Dorsalis pedis artery
Where is the popliteal pulse palpated?
Posterior knee
Where is the plantar pulse palpated?
Medial aspect of bottom of foot near heel
Where is the dorsalis pedis pulse palpated?
Medial aspect of foot, halfway between the big toe and ankle
Where in the ankle does the posterior tibial artery run?
Medially in between the calcaneal tendon and tendons of posterior muscles
What artery does the dorsalis pedis artery give rise to on the dorsal aspect of the foot?
Arcuate artery/arch
What do the medial and lateral plantar arteries form on the plantar surface of the foot?
Plantar arch
How are the arcuate and plantar arches connected?
By perforating arteries
What are the 2 routes by which venous return occurs in the lower limb? How are they different to each other?
Deep- accompanies the arteries
Superficial- close to the limb surface
What is special about the deep venous drainage of the lower limb?
The veins accompany and have the same names as the arteries (the blood just flows in different ways)
What are venae comitantes?
Distal deep veins in the lower limb that arent single
They are multiple veins that form a network of smaller veins with arteries which they accompany. they allow heat exchange and the artery pulse promotes venous flow
How are valves in the lower limb veins arranged?
To only allow distal to proximal flow of blood
What do veins of the lower limb run between and why?
Muscles so that when they contract the blood is also pushed eg the calf pump
What dangerous condition can poor venous drainage in the lower limb cause?
Deep vein thrombosis (DVT)
How do compression socks reduce the risk of deep vein thrombosis?
They squeeze the superficial veins and promote venous drainage via the deep system
What are the 2 main superficial veins of the leg?
Long saphenous vein
Short saphenous vein
What does the long saphenous vein drain into?
The femoral vein
Where does the long saphenous vein run?
Past the anterior malleolus, up the inner leg then pierces the fascia latae to drain into the femoral vein
What does the short saphenous vein drain into?
The popliteal vein
Where does the short saphenous vein run along?
Posterior to lateral malleolus, rungs along the posterior leg then drains into the popliteal veins
What are the superficial veins often harvested for?
Venous grafts, most commonly coronary artery bypass grafts
How are deep and superficial veins connected? What is special about connections between them?
By perforating veins- they have a valve that only allows flow from superficial to deep
What are varicose veins? How do they form?
They form when there is valvular malfunction in the perforating veins between deep and superficial veins. It causes build up of blood in the superficial veins and can be painful. There is higher risk of DVT as venous drainage is impaired
How do lymphatic vessels in the lower limb run?
Alongside veins so there is a deep and superficial set
What are the 2 main sets of nodes in the lower limb? What do they each drain?
Popliteal nodes- drain distal limb
Inguinal nodes- drain limb and pudendal region, perineum, anus and parts of the lower abdomen
What does the superficial posterior leg lymph vessel run along?
The short saphenous vein
What is the femoral triangle outlined by?
Superiorly: inguinal ligament
Medially: adductor longus
Laterally: sartorius
What does the femoral triangle contain?
Femoral nerve
Femoral artery
Femoral vein
Superficial and deep lymph nodes
Out of the femoral artery vein and nerve which is most lateral and which is most medial?
Nerve is most lateral, then artery and vein is most medial
What is the popliteal fossa outlined by?
Superiorly: semimembranosis and biceps femoris muscles
Inferiorly: lateral and medial heads of gastrocnemius muscles
What does the popliteal fossa contain?
Tibial and common peroneal nerves
Popliteal artery and vein
Popliteal lymph nodes
What is the fascia covering the popliteal fossa pierced by?
The short saphenous vein
