Lower Extremity Anatomy PDF

Anatomy Lower Extremity The lower limb Connected to the trunk by the pelvic girdle. There are 6 major regions. (fig 5.1) Gluteal region Femoral region Knee region Leg region Ankle region Foot region Gluteal region Buttocks and the hip…includes thehip joint and the greater trochanter. Clinical n...

Anatomy Lower Extremity The lower limb Connected to the trunk by the pelvic girdle. There are 6 major regions. (fig 5.1) Gluteal region Femoral region Knee region Leg region Ankle region Foot region Gluteal region Buttocks and the hip…includes thehip joint and the greater trochanter. Clinical note ~~ the greater trochanter is often implicated in overuse inflammation and the target of treatment modalities. Femoral region Includes: Sub-trochanteric femur to the supracondylar femur Knee region Includes the distal femur proximal tibia and fibula and the patella. Clinical note ~~ the popliteal fossa is the soft space of the posterior knee region .. This is where the Bakers cyst is formed, usually indicative of meniscal pathology. Leg region Section of tibia and fibula just inferior of knee to just superior to ankle. Clinical note ~~ soft tissue compartments make it susceptible to compartment syndrome. Ankle region Includes distal tibia / fibula andthe articulation with the talus Heavily reliant on ligament forstability Clinical note: Lateral ligament complex and inversion sprain is MC varient ATF Ligament MC specifically Foot region Includes the subtalar joint, tarsal calcaneal joint and extends distally through the phalanges. Bony anatomy of the hip Includes the Ilium, Ischium, andPubis During puberty the 3 main sections of hip bone… ilium, ischium, and pubis.. Solidify via the triradiate cartilage.. And become the hip. All 3 contribute to the formation of the acetabulum Acetabulum faces laterally a n d slightly anterior, allowing it to accept the head of the femur. Femur Proximally consists of: Head Neck Greater and lesser trochanter. Clinical note ~~ the fovea is a medially placed depression in the head for ligament attachment to the acetabulum via ligamentum teres. The femoral neck is a very common site for fracture. Also note the angles of inclination and torsion in fig 5.4 Femur The femoral shaft is mostly smooth and has a slight anterior arc. There is a ridge posteriorly know aslinea aspera. femur The distal femur terminates as themedial and lateral femoral condyles. They articulate with the tibia andform the knee. Patella Is a large sesamoid bone. Is encapsulated in tendon and articulates at the intercondylar groove of the femur. The quad tendon proximally andthe patellar tendon (ligament) distally engulf the patella. MRI of the Knee Tibia Weight bearing bone of leg. Articulates with femur, talus, and with the fibula once proximally and again distally. Proximally this bone widens andflattens out to form the tibial plateau Clinical note~~ the meniscus are attached to the tibial plateau. Tibia The nutrient foramen is located posterior proximal 1/3 and allows major nutrition to tibia. The distal tibia terminates as the flat horizontal section that articulates with talus .. The tibial pilon , as well as a medial projection known as medial malleolus. Fibula Much thinner , the fibula acts mainly as a site for muscle attachment, has no real duty in weight bearing, but does widen and thicken distally to form the lateral malleolus. There is ligamentous attachment at the proximal and distal articulations of fibula to tibia. Fibula Also connecting the tibia and fibula is the sheet of connective tissue known as the interosseouss membrane. The lateral malleolus acts o tsupport the ankle joint. Clinical note~~ lateral ankle fractures and sprains are more common than medial sided injuries. Tarsus, metatarsus and phalanges Tarsus articulates with the leg, iscomprised of the talus, calcaneus,cuboid,navicular and 3 cuneiforms. Talus – articulates superiorly andmedially with tibia and laterally with the fibula Calcaneus – articulates superiorly with talus and anteriorly with cuboid. Tarsus continued Navicular – most medial of this ro w of bones, articulates with talus and cuneiforms. Clinical note ~~ a medial projection of navicular is a fairly common anomaly and may cause medial sided foot pain. Tarsus continued Cuboid – is the lateral border ofthe tarsus in the mid foot. Cuneiforms – set of 3 bones , medial, intermediate and lateral. They articulate with navicular posteriorly , cuboid laterally, and the appropriate metatarsal anteriorly. Metatarsus Consists of 5 metatarsals, connect tarsus and phalanges, and are numbered from medial to lateral 1- 5. Each metatarsal has a head , shaft , and a base. Clinical note ~~ the 3rd metatarsal is often implicated in stress fractures. Phalanges There are 14 phalanges per foot The 1st toe has 2 (proximal and distal) Toes 2-5 have 3 (proximal , middle, and distal) Each has a head, shaft, and base. Lymphatic drainage Lymph drainage of the lower limbruns side by side with venous drainage, and has a superficial and deep division. Superficial and deep lymph vessels accompany the saphenous veins and drain the LE via the popliteal lymph nodes and more proximally the inguinal lymph node system and continue into the external illiac lymph system proximally. Clinical note Lymphadenopathy at the inguinal lymph nodes may indicate malignancies of the genitalia, uterus or perineal abscesses. *Function of the lymphatic system: Runs in tandem with arteriovenous system. Assists in drainage of excess fluid within the tissues. Aids in immunity by filtering out microorganisms. Absorbs and transports fats and fat soluble vitamins. Arterial Feed to LE Arteries of the anterior medial thigh The abdominal aorta divides into the common illiac artery (R + L) in the pelvis. The common illiac divides into the external and internal illiac artery. The external illiac becomes thefemoral artery just distal to inguinal ligament The first major branch, the deepartery of the thigh, supplies muscle in the anterior compartment of thigh. 2 smaller branches of the femoral artery are the lateral and medial circumflex … which feed the femur and adjoining soft tissue. Obturator artery is an extension ofthe internal illiac artery and supplies muscle of the thigh. Other branches of the internal illiac artery include superior and inferior gluteal arteries as well as the pudendal artery. Superior and inferior gluteals supply the 3 gluteal muscles , fascia, and proximal hamstring and quad. Musculature. There are also many perforating arteries which supply muscle and fascia in the thigh. All the arteries in the gluteal areahave nerves that innervate the same structure. Otherwise the femoral artery continues through the adductor canal and terminates just distal to the adductor hiatus…becoming the popliteal artery. Popliteal fossa After the adductor hiatus the femoral artery becomes the popliteal artery, which passes through the popliteal fossa and bifurcates at the popliteus into anterior and posterior tibial arteries. Clinical note ~~ the popliteal artery lays just posterior to the knee joint capsule and must be protected during total knee arthroplasty. Specific to the knee Five genicular branches arise inthe popliteal fossa from the popliteal artery and supply the joint capsule and ligament of the knee. They are : Superior Lateral and superior medial Middle Inferior lateral and inferior medial Arteries of the leg Anterior tibial artery runs in the anterior compartment of the leg just between the tibia and the fibula. Just distal to the inferior extensor retinaculum of the ankle the anterior tibial artery becomes the dorsal artery (dorsalis pedis), which feeds the dorsum of the foot and contributes to the formation of the plantar arch. Clinical note – dorsalis pedis pulse is the detection of the dorsal artery. Plantar arch Distal to the dorsal artery of foot the lateral tarsal, arcuate, and plantar arteries continue to perfuse the bone and soft tissue of the mid and fore foot…eventually terminating in the metatarsal arteries and dorsal digital arties. Arteries of leg Posterior tibial artery is a continuation of the popliteal artery and runs through the posterior compartment …it bifurcates distal to flexor retinaculum into medial and lateral plantar arteries. It feeds the posterior and lateral aspect of leg, tibia and contributes to knee. Plantar Arteries Medial plantar artery feeds the medial side of the sole and great toe Lateral plantar artery continues into the deep arch , feeding the arch and lateral foot……eventually ending in digital arteries. Fibula artery is a branch of the posterior tibial artery and also runs in the posterior compartment. Also feeds the deep posterior compartment , and lateral aspect of the leg. There are many branches of the fibular artery which feed tissue and structure throughout the distal / lateral leg and foot. Venous return of LE The return system somewhat mimics the arterial system. There is a superficial system found in the subcutaneous tissue and a deep system which run deep to the fascia and accompany all major arteries. All have valves. Deep veins are usually paired and flank the artery theyaccompany. Distal to proximal The foot The deep and superficial network in the foot work together to drain the soft tissue and structure As the dorsal metatarsal veins, dorsal venous and plantar venous networks converge with the marginal veins they become the great and small saphenous veins (superficial layer) and anterior tibial ,posterior tibial and fibular veins (deep layer) in the leg. The leg 2 Major superficial veins Great saphenous Ascends anterior to medial malleolus Anastomoses freely with small saphenous Empties into the femoral vein Small saphenous • Ascends posterior to lateral malleolus • Ascends b/n the heads of gastrocnemius • Empties into popliteal vein Clinical note Saphenous vein grafts are occasionally utilized to bypass obstructions. The veins are used in reverse so the valves do not obstruct flow. Venous return is rarely affected due to collateral circulation. Deep veins of the leg Anterior tibial vein bisects the tibia and fibula, crossing to the posterior aspect of the knee Posterior tibial and fibular veins ascend in the posterior aspect of the leg to the posterior aspect of the knee All 3 empty into the popliteal vein in the popliteal fossa. Clinical note Varicose veins are usually caused by valve incompetence between the deep venous circulation and superficial circulation. The pressure from the congestion causes superficial veins to dilate. Lets not forget!! The genicular arterial complex also has a mirror venous complex that empties into the popliteal vein. The Thigh Popliteal vein ascends turning into the femoral vein proximal to adductor hiatus (posterior) Deep vein of thigh, superficial femoral, and great saphenous also ascend and lead into the femoral vein. (anteromedial) Once the femoral vein proceeds proximal to theinguinal ligament it becomes the external illiac vein in the pelvis. Anatomy is fun !!! Muscle of the gluteal region Gluteus maximus Origin – superior posterior ilium Insertion – illiac tibial tract, femur. Innervation – inferior gluteal nerve, L5, S1,S2 - Action – thigh extension, assist in lateral rotation. - Clinical note ~ the superior lateral aspect of gluteus maximus is considered a “safe” area for IM injections Gluteus medius Origin – posterior external surface ilium. Insertion – greater trochanter. Innervation – superior gluteal nerve L45, S1. Action - abduct and medially rotate thigh. Gluteus minimus Origin – posterior inferior aspect of the ilium Insertion – greater trochanter Innervation – superior gluteal nerve L45 S1 Action – abduct, medially rotate thigh Piriformis Origin – anterior surface sacrum Insertion – superior greater trochanter Innervation – branches of S1-2 Action – lateral rotation, abduct thigh and stabilize thefemoral head in acetabulum Clinical note - the insertion of the piriformis is often peeled back for access during total hip arthroplasty, then reattached. Tensor of fascia lata Origin – ASIS Insertion – iliotibial tract Innervation – superior gluteal nerve L5 S1 Action – abduct and laterally rotate thigh, Assists gluteus muscles and provides pelvic stabilization Obturator inturnus, gemelli (sup.&inf.) and quadratus femoris All play a role in lateral rotation and stabilization of femoral head Are innervated by L5 S1 nerve root Are small deep muscles of this region Anterior thigh muscles Together these muscles work to hip flex and extend the knee Include the group known as the “quads” Pectineus Origin – superior ramus of pubis Insertion – on femur just distal to lesser trochanter Innervation – femoral nerve L2 L3 Action – adducts and flexes thigh, assist in medial rotation Flat, square muscle found superio medialy Sartorius Origin – ASIS Insertion – superiomedial tibia Innervation – femoral nerve L2-3 Action – hip – flexion, abduction and lateral rotation ofthigh….knee – flexes leg. “Tailors muscle”..superficial..runs obliquely from lateral tomedial …crosses 2 joints. Clinical note ~ contusion at origin , usually sustained via contact sports, is known as a “hip pointer” Iliopsoas Origin – T12 – L5 vertebral bodies / transverse processes Insertion – lesser trochanter Innervation – L1–2-3 Action – flexion of thigh @ the hip, postural support, active while standing lliacus Origin – iliac crest,iliac fossa, and sacrum Insertion – lesser trochanter and just distal to it Innervation – femoral nerve L2-3 Action – hip flexion, postural support Quadriceps femoris “great extensor of the leg” Bulk of anterior musculature Consists of 4 parts--- Rectus femoris Origin – ant. Inf. illiac spine Insertion – joins with all the vastis muscles at quad tendon and attaches at tibia as the patella tendon Innervation – femoral nerve L2-3 Action – extends knee, helps in hip flexion Crosses hip joint and so helps hip flexion Not as effective a knee extensor when the hip is flexed Vastus lateralis Origin – greater trochanter and lateral linea aspera Insertion – same Innervation – same Action – knee extension Vastus medialis Origin – medial linea aspera Insertion – same Innervation – same Action – knee extension Known as the tear drop muscle due to distal medial prominence at knee Vastus intermedius Origin – anterior and lateral surfaces of shaft of femur Insertion - same Innervation – same Action – knee extension Medial thigh muscles Known as adductor group All innervated by obturator nerve L2-3-4 Adductor longus Origin – pubis, inferior to pubic crest Insertion – mid 1/3rd linea aspera of femur Action – adduction of thigh Most anterior of this group Adductor brevis Origin - Body and inferior ramus of pubis Insertion – proximal linea aspera of femur Action – adducts thigh, assist in flexion Deep to pectineus and adductor longus Adductor magnus Origin – pubis and ischium Insertion – gluteal tuberosity,linea aspera and adductor tubercle of femur Action – adduction,assist in flexion, and hasa function in extension of thigh as well Part adductor, part “hamstring” Obturator externus Origin – obturator foramen margins Insertion – trochanteric fossa of femur Action – lateral rotation of thigh and steadies head of femur in acetabulum Deep, fan shaped muscle in superiomedial aspect of thigh Gracilis Origin – body and inferior ramus of pubis Insertion – superioromedial tibia Action – adducts thigh, flexes leg and medial rotation of leg Only adductor to act at hip and knee, found medially Clinical note ~ it is a weak adductor and so is often harvested for transplantation where muscle has been damaged, usually the hand. Gracilis Harvesting Posterior thigh muscles Semitendinosus, semimebranosus,and biceps femoris are Known as the “hamstrings": make up 3 of the 4 muscles in this group , tibial division of sciatic nerve Cross 2 joints , have 2 actions : hip extension and knee flexion Short head of biceps femoris..not a hamstring, as it crosses only the kneejoint and is innervated by the fibular division of sciatic nerve Semitendinosus Origin – ischial tuberosity Insertion – superiomedial tibia Innervation – L5,S1-2 Tibial sciatic Action – see previous semimembranosus Origin – ischial tuberosity Insertion – posterior medial tibia Innervation – tibial sciatic L5 S1-2 Action – “ “ Biceps femoris long and short Origin – long – ischial tuberosity, short – lateral supracondylar aspect of femur Insertion – lateral head of fibula Innervation – long-tibial sciatic and short – fibular sciatic Anatomy is SUPER-FUN!!! Muscle of the Anterior compartment leg Tibialis anterior – origin –superior lateral 2/3rds tibia Insertion – medial cuneiform and 1st metatarsal Innervation –deep fibular nerve L4-5 Action – dorsiflex the ankle, inverts foot Clinical note ~ micro trauma from stress at attachment point with activity is known as shin splints Extensor hallucis longus Origin – middle fibula Insertion – dorsal base distal phalanx of great toe Innervation – deep fibular nerve L5 – S1 Action – extends great toe , dorsiflex ankle Extensor digitorum longus Origin – lateral condyle of tibia and interosseous membrane Insertion – mid and distal phalanges of lateral 4 digits Innervation – deep fibular nerve L5 S1 Action – extends lateral 4 digits , dorsiflex ankle Fibularis tertris Origin – anterior surface of fibula Insertion – dorsal base 5th metatarsal Innervation – deep fibular nerve L5-S1 Action – dorsiflexion, assist in eversion Muscle of the Lateral compartment Fibularis longus – origin – head and superior 2/3rds lateral fibula Insertion – base 1st metatarsal and medial cuneiform Innervation – superficial fibular nerve L5 – S1-2 Action – evert foot, assist plantar flexion Fibularis brevis Origin - inferiolateral fibula Insertion – dorsal 5th metatarsal base Innervation – superficial fibular nerve L5 S1-2 Action – evert foot , assist plantar flexion Superficial Muscle of the Posterior compartment Gastrocnemius – origin – lateral head ~ lateral aspect lateral femoral condyle…..medial head ~ popliteal surface of femur Insertion – posterior surface calcaneus via calcaneal tendon Innervation – tibial nerve S1-2 Action – plantarflexion of ankle, assist flexion of knee Soleus Origin – posterior head of fibula posterior tibia Insertion – posterior calcaneus Innervation- tibial nerve S1-2 Action – plantar flexion of ankle plantaris Origin – supracondylar line of femur Insertion – posterior calcaneus Innervation – tibial nerve S1-2 Action – weak assist plantar flexion Deep muscle of the posterior compartment Popliteus -Origin – lateral aspect lateral condyle of femur Insertion – posterior surface of tibia Innervation – tibial nerve L4-5 S1 Action – weakly flexes knee , unlocks it from full extension Flexor hallicus longus Origin – posterior inferior aspect of fibula Insertion – base of distal phalanx of great toe Innervation – tibial nerve S2-3 Action – flexes great toe Flexor digitorum longus Origin – medial inferior aspect of tibia and fibula Insertion – bases of distal phalanges of lateral 4 toes Innervation – tibial nerve S2,S3 Action – flexes lateral 4 toes * Clinical Note: Can be used for PTT reconstruction. Tibialis posterior Origin – posterior inferior tibia and fibula Insertion – navicular , cuneiforms, cuboid and bases of metatarsals 2-4 Innervation – tibial nerve L4-5 Action – plantar flex ankle , inverts foot Illiotibial Band Is a continuation distally of the tensor of fascia lata, and gluteus maximus acts as a lateral support / aponeurosis for the muscle of the anterolateral thigh. It attaches on the lateral proximal tibia Clinical note ~ lateral knee pain that migrates proximally , usually in an active patient … consider ITB friction syndrome. Compartment syndrome Strong septum's divide the compartments of the leg With pressure changes compartment syndromes are an emergent concern The 5 ps of compartment syndrome are pain, pallor, paresthesia, paralysis andpulselessness A fasciotomy may be necessary to avoid tissue damage / ischemia Compartments lower leg https://www.youtube.com/watch?v=XXp0EtKtlF8 Dermatomes Sensation in subcutaneous and cutaneous tissue ofthe lower limb is supplied by the branches of the lumbar and sacral plexus. Figure 5.9 in text illustrates the dermatonal pattern of L1- L5 as well as S1S4. Know this Nerves of the lower extremity Regional Anesthesia: Spinal/epidural and peripheral nerve blocks are used for a variety of procedures. Can be used for intraoperative anesthesia and post-operative pain control. Reduces the amount of pain medication required during surgery and post-operatively. Common peripheral nerve block locations include: Adductor canal Popliteal Important nerves clinically Sciatic nerve Largest nerve in body Up to 19% of patients with posterior hip dislocation experience some sciatic nerve dysfunction Sciatica can be diagnosed via positive straight leg raise, and tenderness to palpation in the sciatic notch of pelvis Superior gluteal nerve to superior gluteal nerve results in a weakness of gluteus medius. causes a pelvic tilt with ambulation and a “gluteal gait ” A positive trendelenburg test indicates superior gluteal nerve dysfunction. Injury This Patellar tendon reflex Strike the patellar tendon / ligament and the leg extends Tests the L2 – L4 nerves (Quads) Common fibular (peroneal) nerve Branch of sciatic nerve Wraps around the fibula head (superficial) leaving it susceptible to injury Dysfunction may cause foot drop Sural nerve Sural nerve grafts are often employed to replace damaged nerve Plantar reflex Blunt object is dragged from the heel to the base ofthe 1st toe Normal response ( after 4-5 years of age) is the toescurl down A babanski sign (1st toe extends and remaining toesfan out) is abnormal and indicates brain injury or cerebral disease. The femoral triangle Is a subfascial space found in the anterosuperior 1/3rd of thethigh Contains : femoral nerve, femoral artery, femoral vein, deepinguinal lymph nodes Joints Hip Large multiaxial,ball and socket joint Stabilized by ligament as well as muscle Has a synovial capsule Articulative surface is covered with hylan cartilage While standing the entire weight of the upper body is transmitted through the hip joint Major supporting ligaments Anteriorly by the iliofemoral ligament Inferiorly and anteriorly by the pubofemoral ligament Posteriorly by the ischiofemoral ligament Knee Primarily a hinge joint Has synovial capsule Supported primarily by ligament Articular surfaces covered by hylan cartilage Joint space maintained by a medial and lateral meniscus Major supporting structures Medial and lateral collateral ligament … prevent valgus and varus Anterior and posterior cruciate ligament …… prevent anterior and posterior translation of tibia from femur Ankle Hinge joint Synovial capsule Articular hylan cartilage Major supporting structures Lateral …. Prevent inversion Anterior talofibular “ATF”, posterior talofibular, and calcaneofibular ligaments Medial…… prevent eversion A complex of ligaments known as the deltoid ligament complex Clinical note ~ lateral ligament sprains are far more common than medial. QUESTIONS???? HAVE A GOOD DAY !!!