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Neurovasculature of the Lower Limbs Manchester T&O socLearning outcomes By the end of this lecture and private study, you should be able to: • Describe the arterial supply of the lower limb • Describe the venous drainage of the lower limb • Describe the lymphatic drainage of the lower limb • Describe the nerve supply of the lower limb Slides & cert of attendance will be available after completion of feedback form at the endArterial supply • Oxygenated blood is ejected by the left ventricle to the ascending aorta à aortic arch à descending aorta (thoracic and abdominal) • common iliac arterieserminates into left and right • At sacroiliac joint, common iliac arteries give rise to external and internal iliac arteries • External iliac artery supplied the majority of the lower limb while the internal iliac also contributes Internal iliac arteries: Branches – anterior & posterior Anterior trunk • Obturator artery – lies on lateral wall of pelvis and passes through obturator canal (supplies muscles of the thigh’s adductor region) • Inferior gluteal artery – enters the gluteal region via the greater sciatic foramen, below piriformis muscle (supplies gluteal muscles and hip joint) • Internal pudendal artery - moves inferiorly to exit the pelvis via the greater sciatic foramen (main blood supply to perineum) • Umbilical, superior vesical, inferior vesical, middle rectal, vaginal female & uterine (female) arteries Posterior trunkInternal iliac arteries: Branches – anterior & posterior Posterior trunk • Superior gluteal artery – exits the pelvic cavity via the greater sciatic foramen, enters the gluteal region superiorly to the piriformis muscle (major blood supply to the muscles and skin of the gluteal region) • Iliolumbar, Lateral sacral arteries Posterior trunk In the thigh • Femoral artery & branches • Profunda femoris & branches External iliac à Femoral artery • M & L circumflex femoral etc • External iliac artery passes under the inguinal ligament and become femoral artery • Pulse: inferior to midpoint of the inguinal point • Gives off • Superficial epigastric artery • Superficial circumflex iliac artery • External pudendal arteries • Profunda femoris artery • Descends in the femoral triangle • Enters adductor canal to pass into the popliteal fossa In the thigh • Femoral artery & branches • Profunda femoris & branches Femoral artery à Profunda femoris • M & L circumflex femoral etc • Arises from the lateral aspect of the femoral artery and runs inferiorly between adductor longus and magnus, supplying the thigh musculature • Gives off: • Medial circumflex femoral artery • Lateral circumflex femoral artery • 3-4 perforators • There are rich anastomoses around the hip with the gluteal vessels (branches of internal iliac) and around the knee In the thigh • Femoral artery & branches • Profunda femoris & branches Blood supply of hip joint • M & L circumflex femoral etc Cruciate anastomosis • Medial circumflex femoral artery (and retinacular branches) • Lateral circumflex femoral artery • Obturator artery (and artery to head of femur) Trochanteric anastomosis • Medial circumflex femoral artery • Lateral circumflex femoral artery • Superior gluteal artery Note the retinacular vessels (branches of medial & lateral circumflex arteries) passing from the neck to the head of femur • Inferior gluteal artery An intracapsular neck of femur fracture can damage these blood vessels, removing the blood supply to the femoral head, leading to avascular necrosis Collateral circulation If there is a blockage between the external iliac artery and femoral artery, blood can reach the popliteal artery by: • Internal iliac à inferior gluteal artery à a perforating branch of the profunda femoris artery à the lateral circumflex artery à its descending branch à the superior lateral genicular artery à the popliteal artery • Via the anastomoses between obturator artery and branches of profunda femoris In the leg In the foot • Popliteal • AT • DP Popliteal artery • TPT • PT • PT • Peroneal • Moves through the popliteal fossa, between hiatus tendinous and lower border of popliteus muscle • Deepest structure in the popliteal fossa (difficult to get a pulse) • Medial aspect of the popliteal fossa • Gives rise to 5 genicular branches • Supplies the knee joint • It ends as the posterior and anterior tibial arteries Second most common site of aneurysm May be compromised in dislocation of the knee and fractures of the lower femurBlood supply of knee joint • 5 Genicular arteries • Branches of the femoral artery • Branches of the profunda femoris • A branch from the anterior tibial artery joint and form the genicular anastomosis In the leg In the foot • Popliteal • AT • DP Anterior tibial artery • TPT • PT • PT • Peroneal • Passes anteriorly superior to the interosseal membrane • Descends between the tibialis anterior and extensor digitorum longus • Accompanied by deep fibular nerve • Supplies the muscles in the anterior compartment of the leg (dorsiflexors) • At ankle, it becomes the dorsalis pedis artery In the leg In the foot • Popliteal • AT • DP Dorsalis pedis • TPT • PT • PT • Peroneal • Is a continuation of anterior tibial artery • The dorsalis pedis supplies the dorsum of the foot along with its branches: lateral tarsal, deep plantar, arcuate, 1st dorsal metatarsal. These branches give rise to dorsal digital arteries of the phalanges • Dorsalis pedis pulse is felt in the first intermetatarsal space, between the extensor digitorum longus and extensor hallucis longus tendons In the leg In the foot • Popliteal • AT • DP Posterior tibial artery • TPT • PT • PT • Peroneal • Accompanies the tibial nerve as it descends deep to the soleus muscle • Gives off the fibular, circumflex fibular, and nutrient arteries • Supplies the muscles of the posterior compartment of the leg (plantar flexors) • Becomes the medial and lateral plantar arteries after running posterior to the medial malleolus • Pulse can be felt behind the medial malleolus In the leg In the foot • Popliteal • AT • DP Lateral and medial plantar arteries • TPT • PT • PT • Peroneal • Posterior tibial artery splits the medial and lateral plantar arteries after running posterior to the medial malleolus • The medial and lateral plantar arteries supply the sole of the foot along with their branches: superficial and deep plantar arches, respectively • The deep arch gives rise to plantar digital arteries of the phalanges Plantar aspect of foot Superficial veins Deep veins • Great saphenous Of the foot & leg • Small saphenous • Dorsal venous arch Superficial veins of the lower limb • AT, PT, fibular, popliteal Of the thigh • Profunda femoris • Femoral • Originate from the dorsal venous network of the foot and dorsal veins of foot • Great (long) saphenous vein ascends 2.5.cm anterior to the medial malleolus, posterior to medial condyle of femur (hands breadth behind patella) • Pierces the fascia lata to join the femoral vein • Small (short) saphenous vein ascends posterior to lateral malleolus and penetrates the deep fascia of the leg between the heads of the gastrocnemius muscle • Merges with deep veins to form the popliteal vein Superficial veins Deep veins • Great saphenous Of the foot & leg • Small saphenous • Dorsal venous arch Deep veins of the lower limb • AT, PT, fibular, popliteal Of the thigh • Profunda femoris • They ascend beneath the deep fascia of the lower • Femoral limb • As a general rule, the deep veins accompany and share the name of the major arteries in the lower limb. • Often, the artery and vein are located within the same vascular sheath – so that the arterial pulsations aid the venous return. • Main venous structure in the foot = dorsal venous (Profunda into anterior tibial veinrficial veins, some drain femoris vein) • M & L plantar veins à combine to form the posterior tibial and fibular veins • AT + PT + fibular à popliteal & enter the thigh through the adductor canal à femoral vein • Mfemoris vein à drains into femoral veinfunda • Femoral vein exits the thigh & becomes the external iliac vein after passing under the inguinal ligamentVenous blood flow • Venous flow is from superficial to deep veins, via perforators • Arterial pulsation, negative intra-thoracic pressure and contraction of muscles (muscle pump) all help venous return to the heart, against gravity • Valves prevent against backflow If the valves in veins become incompetent, blood can flow back into the superficial veins, causing veins to dilate, resulting in varicose veins. Lymphatic vessels à Lymphatic nodes • Superficial • Inguinal • Deep • Superficial Lymph drainage of the lower limbs • Deep • Popliteal • Superficial lymph vessels accompany the superficial veins • The lymph vessels accompanying the great saphenous vein drain to the superficial inguinal lymph nodes leading to the deep inguinal lymph nodes then the external iliac nodes • The lymph vessels accompanying the small saphenous vein enter the popliteal lymph nodes • Deep lymph vessels accompany deep veins and enter the popliteal lymph nodes, accompany femoral vein to the deep inguinal nodes Lymphatic vessels à Lymphatic nodes • Superficial • Inguinal • Deep • Superficial Superficial inguinal nodes • Deep • Popliteal • “T” along inguinal ligament (horizontal grp) and saphenous vein (vertical grp) • Outside the femoral triangle (superficial to the fascia lata) along with the great saphenous vein and its tributaries • Receive lymph from: • Anterior abdominal wall (under umbilicus) • Skin of back (below iliac crests) • Perineum • Gluteal region • Superficial lower limb Lymphatic vesselsà Lymphatic nodes • Superficial • Inguinal • Deep • Superficial Deep inguinal nodes • Deep • Popliteal • Inside the femoral triangle, medial to femoral vein • Femoral canal is a short and conical space between the medial wall of the femoral sheath and the femoral vein – contains deep inguinal lymph nodes • Receive lymph from: • Lower limb (accompanying the femoral vessles, imclduing popliteal nodes) • Superficial inguinal nodes (some can proceed directly to external iliac nodes • External genitaliaDeep and superficial inguinal nodes drain to • External iliac nodes • Common iliac nodes • Lumbar lymph nodes • Cisterna chyli • Thoracic duct • Pirogov’s venous angle (left) • Venous system Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Lumbar plexus – Sacral plexus • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • Lumbar and sacral (lumbosacral) plexuses = ventral rami of L1-S4 • Supply the lower limbs, parts of the abdominal wall, pelvis and perineum (for this lecture will focus only on the nerves supplying the lower limbs) (Ventral rami) Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Lumbar plexus (L1-4) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • ventral rami of L1-L4 • formed within the psoas major muscle and anterior to the transverse processes of the lumbar vertebrae • has motor and sensory branches Note: A useful memory aid for the branches of the lumbar plexus is: I, I Get Leftovers On Fridays. This stands for the Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral cutaneous nerve of the thigh, Obturator and Femoral. Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Femoral Nerve (L2-4) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • Descends behind the inguinal ligament • Passes through the femoral triangle into the thigh • Gives off muscular, anterior cutaneous femoral and saphenous branches • Sensory Innervation • Skin on anterior surface of the thigh (by the anterior cutaneous femoral branch) • Skin of the medial leg and foot (by the saphenous nerve) • Motor Innervation • Innervates the muscles of the anterior thigh – the illiacus, pectineus, sartorius and quadriceps femoris. Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Saphenous nerve (L3-4) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • The terminal cutaneous branch • Enters the adductor canal with femoral vessels • Pierces the medial wall of the adductor canal and become superficial • Accompanies the great saphenous vein in the leg • Supplies the skin on the medial surface of the knee, anteromedial surface of leg and medial malleolus Saphenous nerve may be at risk in venous access or varicose vein surgery Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Obturator nerve (L2-4) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • Travels anteriorly on lateral pelvic • Sensory innervation wall towards obturator canal • Upper half of medial thigh • Passes through obturator canal • Motor innervation and enters the medial aspect of the • Obturator externus thigh • Muscles in the medial compartment of the thigh: adductor magnus, adductor longus, adductor brevis and gracilis Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Sacral plexus (L4-S4) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • formed by ventral rami of L4 and L5 (the lumbosacral trunk) and S1-4. • located on the surface of the posterior pelvic wall, deep to the piriformis muscle A useful memory aid for the major branches of the sacral plexus is ‘Some Irish Sailor Pesters Polly’. This stands for Superior Gluteal, Inferior Gluteal, Sciatic, Posterior cutaneous nerve of thigh, Pudendal. Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Gluteal nerves • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 Superior gluteal nerve (L4-S1) Inferior gluteal nerve (L5-S2) • Exits pelvis through greater sciatic foramen, enters gluteal • Exits pelvis through greater sciatic foramen, region superiorly to the piriformis muscle enters gluteal region inferiorly to the • Runs laterally between the gluteus medius and minimus piriformis muscle • Supplies gluteus medius, gluteus minimus and tensor fascia lata • Innervates gluteus maximus • No sensory function • No sensory function Piriformis Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Sciatic nerve (L4-S3) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • Enters the gluteal region through greater sciatic foramen inferior to piriformis – does not supply any structure in the gluteal region • Descends deep to gluteus maximus, midway between the ischial tuberosity and the greater trochanter, behind the hip joint Intragluteal injections should only be performed in the superolateral quadrant of the buttock, away from the sciatic nerve Lumbar plexus L1-4 Sacral plexus L4-S4 • Femoral nerve L2-4 • Gluteal nerves • Saphenous nerve L3-4 • Superior L4-S1 Sciatic nerve (L4-S3) • Obturator nerve L2-4 • Inferior L5-S2 • Sciatic nerve L4-S3 • In the posterior compartment of the thigh, it descends between the adductor magnus and bicep femoris • The sciatic nerve usually gives off its terminal branches at the apex of the popliteal fossa but in some cases can branch near the piriformis • Sensory Innervation • Motor Innervation • Muscles in the posterior compartment of the thigh – hamstring muscles • Adductor magnus (in addition to obturator nerve) • Sciatic nerve L4-S3 • Tibial nerve • M & L plantar Tibial nerve (L4-S3) • M calcaneal • Common fibular nerve • Deep • Superficial • Passes into the sole behind medial malleolus, deep to the flexor retinaculum • Divides into the medial and lateral plantar nerves • Sensory Innervation • Ankle joint • Skin of the heel • Motor Innervation • Plantaris • Popliteus • Muscles in the superficial posterior compartment of the leg; gastrocnemius and soleus • Muscles in the deep posterior compartment; tibialis posterior, flexor hallucis longus and flexor digitorum longus • Sciatic nerve L4-S3 • Tibial nerve • M & L plantar Tibial nerve (L4-S3) • M calcaneal • Common fibular nerve • Deep • Superficial The tibial nerve also supplies all the sole of the foot via three branches: • Medial calcaneal branches: These arise within the tarsal tunnel, and innervate the skin over the heel. • Medial plantar nerve: Innervates the plantar surface of the medial three and a half digits, and the associated sole area. • Lateral plantar nerve: Innervates the plantar surface of the lateral one and a half digits, and the associated sole area. Cutaneous innervation of sole • Sciatic nerve L4-S3 • Tibial nerve • M & L plantar Common [peroneal] Fibular Nerve (L4-S2) • M calcaneal • Common fibular nerve • Deep • Superficial • Descends laterally in the popliteal fossa towards the lateral compartment of the leg • Gives off lateral sural cutaneous branch (sensory) • Winds around the neck of the fibula and then divides into its terminal branches • Supplies the short head of biceps Plaster cast compression or trauma to the nerve – can lead to foot dropSural nerve • Formed by lateral cutaneous sural branch from the common fibular nerve and medial cutaneous sural branch from the tibial nerve • May be used as a nerve graft • Supplies the skin on the lower posterolateral surface of the leg and the lateral side of the foot and little toe • Sciatic nerve L4-S3 • Tibial nerve • M & L plantar Deep fibular nerve (L4-5) • M calcaneal • Common fibular nerve • Deep • Superficial • Arises between fibularis longus and neck of fibula • Sensory innervation • Passes between tibialis anterior and extensor digitorum • Space between the 1st and 2nd toes longus, descending down the interosseous membrane – accompanied by the anterior tibial artery • Motor innervation • Muscles in the anterior compartment of the leg; tibialis • Enters the dorsum of the foot passing under the extensor anterior, extensor hallucis longus, extensor digitorum retinaculum longus, fibularis tertius • Gives rise to dorsal digital nerve to toes 1-2 • Extensor digitorum brevis • Extensor hallucis brevis • Sciatic nerve L4-S3 • Tibial nerve • M & L plantar Superficial fibular nerve (L5-S2) • M calcaneal • Common fibular nerve • Deep • Superficial • Arises between fibularis longus and neck of fibula • Sensory innervation • Descends in lateral compartment of the leg • Skin on anterior distal leg • Skin on dorsum of foot • At distal 1/3 of leg, emerges from the deep fascia • Motor Innervation • Gives rise to cutaneous branches and dorsal digital nerves to 2nd-5th toes • Mlongus and fibularis brevisrtment of the thigh; fibularisReferences • My own notes • TeachMeAnatomy • Moore et al. Clinically Oriented Anatomy • Hansen JT. Netter's Clinical Anatomy • Putz & Pabst. Sobotta Atlas of Human Anatomy With special thanks to Dr. Enis Cezayirli Scan me J Thank you for listening! Please leave some feedback J Slides and certificates will be sent out after completion of feedback form Gluteal region and thigh next Thursday! Make sure to sign up J
