anatomy of leg
Terms
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- iliopsoas
- psoas major and iliacus; run deep to inguinal ligament; only muscle that attaches to lesser trochanter; most powerful flexor of hip; forms part of floor of femoral triangle
- pectineus
- arises from pecten of pubis and runs down to attach into pectineal line, which is small elevation just distal to lesser trochanter; some flexion of thigh, can adduct, and some internal rotation
- sartorius
- arises from ASIS, runs distally and attaches into medial tibia, a specialized tendinous component, pes anserine; runs lateral to medial; flex knee, externally rotate hip, abduct hip, flex thigh
- tensor fascia lata
- internal rotato; pulls IT band anteriorly; primary function is to flex hip by assisting iliopsoas and rectus femoris
- remaining adductors
- adductor longus-arises from inf pubic ramus and inserts into medial lip of linea aspera; gracilis-nearby origin sinilar to longus and runs down and attaches to medial tibia
- quads
- rectus femoris, vastus intermedius, lateralis, medialis; functions: flex hip, extend knee; dislocate patella laterally (lower horizontal fibers of medialis compensate)
- pes anserine
- 3 muscles descend and interdigitate; sartorius, gracilis, semitendonius-attach to medial knee (upper medial aspect of tibia) and help reinforce medial knee jt; reinforces laterally with anserine bursa-one of the most commonly inflamed bursae of body
- vastus intermedius
- deep portion is special part called articularis genu-doesn't run with other parts of muscle but goes directly into capsule (superior aspect of capsule-suprapatella bursa); muscle contract millisecs before full extension of knee and pulls redundant suprapatella bursa out of way
- Gerdy's tubercle
- lateral epicondyle of tibia; attachment of the thickening of fascia lata called iliotibial band; 2 muscles attach: tensor fascia lata
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femoral triangle
(Scarpa's) - inguinal lig, sartorius, adductor longus; N-A-V-L (lat to med)
- adductor canal
- vastus medialis (anterolateral), adductor longus and magnus (posteriorly), med border of subsartorial canal (roof); carries femoral neurovascular structures, cutaneous br. of obturator n to medial thigh, 2 br. of femoral n-nerve to vastus medialis and saphenous n (cutaneous br + longest n)
- obturator nerve
- lumbar plexus (L2-L4); anterior branch-supplies gracilis, adductor longus and brevis; posterior br- supplies adductor magnus and brevis (maybe)/ innervates both the hip (ant br) and knee jts (post br)
- tibial nerve
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innervates every muscle in posterior leg; soon as crosses with medial malleolus, divides into medial and lateral plantar nerves to supply muscles and skin of plantar surface of foot; before this division, the medial calcaneal cutaneous nerve branches off
*lateral calcaneal cutaneous nerve supplied by sural nerve* - femoral nerve
- remaining muscles of ant thigh except tensor fascia lata (quads and sartorius); innervates knee and hip jts
- Glutes
- minimus-attaches between anterior and inferior gluteal lines; medius-between anterior and posterior lines; maximus-attaches to ilium posterior to posterior line
- hamstrings
- true hamstrings arise from ischial tuberosity, cross the hip and knee jts, and attach to tibia or fibula; from lateral to medial-biceps femoris (long and short heads), semitendinosus, semimembranous (oblique popliteal lig); biceps tilted laterally, semi's tilted medially; primarily supplied by branches of perforating aa (from deep femoral a, which run along tibial nerve)
- gluteus maximus
- largest muscle of body; arises from posterior of posterior line, sacrum, coccyx, and deeply from sacrotuberous ligament; 1/4 inserts into femur on 3rd trochanter, 3/4 inserts into IT band; innervated by inferior gluteal nerve; primary function is to give short burst of extension in thigh but also involved in lateral rotation of hip
- gluteus medius
- originates btwn ant and post gluteal lines and above ant gluteal line to run all the way to iliac crest; gluteal injection; inserts into greater trochanter (directly lateral to gr troch-allows muscle to be a good adductor); superior gluteal nerve
- gluteus minimus
- arises from inferior to inferior gluteal line and attaches to greater trochanter (more anterior); primarily internal rotator of hip, can assist in abduction; superior gluteal nerve
- piriformis
- arises from S2-S4; lateral rotator of hip; fills the majority of diameter of greater sciatic foramen
- superior and inferior gamellus (triceps coxae)
- superior-arises from ischial spine; inferior-arises from ischial tuberosity; lateral rotators; attach medial aspect of greater trochanter
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obturator internus
(triceps coxae) - inferior to ischial spine, takes 90 deg bend and runs out to attach to greater trochanter
- quadratus femoris
- inferior to inferior gamellus; arises from ischial tuberosity and runs laterally to attach to quadrate tubercle (on trochanteric crest)
- obturator externus
- leaves external aspect of pelvis and runs around anterior or deep to quadratus femoris and attaches to quadrate tubercle (crest)
- lateral rotators of hip
- piriformis, 2 gamellae, 2 obturator and quadratus femoris
- anomaly of sciatic n
- in 12% of people, sciatic nerve divides near the piriformis (pierces piriformis); in 0.5%, sciatic divides early with the common peroneal n running superior to piriformis (can be entrapped)
- popliteal fossa
- diamond shape, borderd medially by semimembranosus, laterally by biceps femoris tendon, and inferiorly by 2 heads of gastrocnemius; posterior to anterior:nerves of sciatic, popliteal vein, popliteal artery
- deep to fossa, 2 muscles
- 1)plantaris; 2) popliteus-1st muscle to contract when flexing knee from full extension (unlocks knee so hamstrings can take over; one of 2 muscles to pierce a joint capsule)
- two thickenings of posterior knee
- 1)oblique popliteal lig (of Winslow); 2)arcuate popliteal lig
- deep femoral artery
- also known as profundi femoral artery-branches: medial circumflex-supplies proximal femur; lateral circumflex-surrounding muscles and soft tissue; 4 perforating branches-branch that perforates some of adductor muscles and terminate primarily in hamstrings
- hip jt innervation
- femoral, obturator (anterior), superior gluteal , n to quadratus femoris (?)
- cribiform fascia
- defect in fascia lata for great saphenous vein to penetrate
- great saphenous vein
- longest vein, begins from dorsal venous arch in foot, runs anterior to medial malleolus, runs up medial part of leg, thigh and drains into femoral
- SI joint
- small, synovial jt; 4 deg of mobility (can increase during gestation for females); fuses around 4th decade for men, 5th decade for women; more ligamentous support posteriorly than anteriorly
- genicular anastomisis around the knee
- 5 genicular artery branches (off popliteal); descending genicular branch of femoral a, descending genicular br of lateral femoral cutaneous a, anterior recurrent and circumflex fibular branches of anterior tibial artery
- ligaments of knee
- 1)extracapsular; 2)capsular; 3)intracapsular
- intrinsic ligs of knee
- patellar-runs from apex of patella to tibial tuberosiy, distal end of quadriceps femoris tendon, helps replace fibrous capsule anteriorly; oblique popliteal-expansion from semimembranous muscle, reinforces posterior aspect; arcuate popliteal-Y-shaped wtih stem attached to head of fibula, passes over popliteus muscle; tibial collateral (MCL)-runs from medial epicondyle of femur to medial condyle of tibia and upper part of medial surface of tibia
- extrinsic ligs of knee
- fibular collateral (LCL)-lies deep to tendon of biceps femoris, extends from lateral epicondyle of femur to head of fibula, separated by from lateral meniscus by tendon of popliteus
- intracapsular ligs
- anerior cruciate (ACL); posterior cruciate (PCL); Posterior meniscofemoral
- muscles around knee
- muscles are main support for knee (not ligaments); well-toned quadriceps femoris can help prevent injury, especially lower fibers of vastus medialis and lateralis-send off aponeurotic expansions called medial and lateral patellar retinacula-attach to sides of patella and keep aligned; tendency to displace patella laterally (quads) but is prevented by lower fibers of vastus medialis, which run horizontally
- muscles and knee movements
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1)Quads-extension-primarily rectus femoris
2)hamstrings-flexion
3)lateral rotators-biceps femoris (inserts on lateral aspect of fibular head)
4)medial rotators-semimembranosus, semitendinsus, and popliteus(when leg is flexed) - popliteus muscle
- arises from lateral epicondyle of femus inside knee joint and passes immediately downward and medially to insert into upper posterior aspect of tibia; when knee is fully extended, tibia is fixed, and popliteus can pull femur and laterally rotate it; "key of the knee"
- clinical assns of knee
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1)Unhappy triad-foot is fixed and leg is forcibly abducted, stressing medial aspect of knee; tears ACL, MCL (or tibial) and medial meniscus
2)anterior drawer sign-pull leg forward to check for excessive anterior movement of tibia on femur; checks ACL tear
3)posterior drawer sign-push on leg to check for excessive posterior movement; tests PCL - clinical assns *continued*
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1)arthroscopy-trim lateral meniscus; ACL graft from patella lig or hamstring tendon
2)prepatella bursitis-pple who work on knees causes excess synovial fluid or blood in bursa or joint cavity; aspirate from lateral aspect with knee slightly flexed (use triangular area:lateral epicondyle of femur, apex of patella, Gerdy's tubercle) - saphenous nerve (off femoral)
- cutaneous: anteromedial leg (not thigh)
- lateral sural cutaneous nerve (off common fibular)
- antero- and postero- lateral aspects
- medial sural cutaneous nerve (off tibial)
- between saphenous and lateral sural nerves
- superficial fibular nerve
- distal lateral
- musculovenous pump
- perforating veins have one-way valves, only permit flow from superficial to deep; in lower limb, blood is pumped against gravity by contraction of muscle (deep fascia is around muscles so pressure exerted is on deep veins
- tibia
- only weight bearing bone of leg-transfers all weight from femur to talus; proximally expands to form medial and lateral tibial condyles with intercondyle area btwn; triangular bone with 3 surfaces: anterior and medial, are subcutaneous and palpable (shin), and lateral surfaces; medial malleolus-distal, anterior prominence with lateral facet for talus articulation; inferior end of tibia also has articulation facet for talus
- fibula
- long, slender with head, neck and shaft; ends distally as lateral malleolus projects 1 cm farther than medial on tibia; articulates with talus on its medial aspect; most of shaft and neck are covered with muscles and not subcutaneous, but distal part of shaft and lateral malleolus are subcutaneous (palpable)
- interosseus membrane
- most fibers run inferior from tibia to fibula: 8 of 9 muscles attaching to fibula pull downward (exception: biceps femoris) and this resists downward pull
- tibia-fibula articulation
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1)superior tibiofibular jt-plane, synovial with is flat and planar
2)inferior tibiofibular jt-syndesmosis, a fibrous jt where bones are united by ligs-integrity of this jt for stability of ankle jt b/c lateral malleolus has to be pressed against talus - ankle jt movements
- dorsiflexion and plantarflexion
- anterior compartment of anterolateral leg
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function: dorsalflexion and some toe extension
innervation: deep fibular nerve (off common fibular)
blood: anterior tibial artery and veins (off popliteal) - posterior compartment of AL leg
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function: plantarflexion and flexors of toes
innervation: tibial nerve
blood: posterior tibial artery and veins - lateral compartment of AL leg
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function: eversion of foot
innervation: superficial fibular nerve
blood: fibular artery, br of posterior tibial artery - deep fascia modifications
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extensor retinacula-pass into dorsum of foot
fibular retinacula-tendons of lateral comp. as pass behind lateral malleolus
flexor retinacula-posterior compartment; for deep posterior compartment:runs superiorly from medial malleolus and inferiorly from calcaneus; has septations to give own compartments (TP,FDL,NVB,FHL) - Anterior compartment: tibialis anterior
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arises from lateral surface of upper 1/2 of tibia and inserts into medial cuneform of foot and into base of 1st metatarsal
function:passes in front of ankle to dorsiflex and invert - Anterior compartment: extensor hallicus longus
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arises from middle 1/2 of fibula (medial) and interosseus membrane, inserts into distal phalanx of great toe
function: dorsiflexes and extends great toe - Anterior compartmen: extensor digitorum longus
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arises from upper 3/4 of fibula (medial) and I.M.; tendon splits into 4, each passing to lateral 4 toes via an extensor expansion, which to middle and distal phalanges of long toes
function: dorsiflexes and extends lateral 4 toes - Anterior compartment: fibularis tertius
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continuation of EDL, origin is distal portion of fibula (medial) and tendon attaches to base of 5th metatarsal
function: dorsiflexion and everter (inserts on lateral side) - Lateral compartment of AL leg: fibularis longus
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more superficial; origin is head and upper 2/3 of shaft of fibula, attaches after passing behind lateral malleolus and inserts onto medial cuneiform and base of 5th metatarsal
function: everts and plantarflexion - Lateral compartment: fibularis brevis
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arises lower 2/3 of shaft of fibula, attaches after passing lateral malleolus onto tuberosity of base of 5th metatarsal
function: everter and plantarflexion - clinical assns: fibula
- middle 1/3 used for bone grafts and has nutrient artery so retains its own blood supply
- C.A.: fibular nerve
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Foot Drop: common fibular nerve is directly adjacent to neck of fibula; fracture or compression will paralyze all muscles of anterior and lateral compartment of leg (dorsiflexors)
*most frequently damaged nerve of lower limb* - compensation for Foot Drop
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"long limp"
swing out foot
"steppage gate"-extra flexion of thigh and knee - Posterior compartment: gastrocnemius
- arises off the lateral and medial supracondylar regions of femur and runs distally to calcaneous; small saphenous vein and sural nerve run in btwn 2 bellies; can flex knee and plantarflex foot (short spurts)
- Posterior compartment: plantaris
- absent in 10%; can fuse into Achilles tendon or insert directly into calcaneus; tendon known as "freshman's nerve"
- Posterior compartment: soleus
- homologue of flexor digitorum superficialis; attachments are off tibia (posterior), fibula (head, neck, and proximal 1/3), and sometimes I.M. <makes inverted "U">; *strongest plantarflexor*; arcus tendineus of soleus is where popliteal vessels and tibial nerve descend to posterior leg
- Posterior compartment: flexor hallucis longus
- arises from fibula (laterally); runs up to base of distal first phalanx; if lost, lose "spring in step"; enters fibrotic canal with actual ledge of bone from calcaneus *sustentaculum talli* which tendon runs inferiorly to ledge and uses it as a pulley
- Posterior compartment: flexor digitorum longus
- arises from tibia (medially); runs to base of distal phalanx of digits 2-5; FHL and FDL criss-cross (decussate) each other *Knot of Henry*
- tibialis posterior
- in the middle, arising from tibia , fibula, and I.M.; "claim to fame"-attaches to every bone of midfoot, which includes navicular, cuboid, and cuneiform as well as metatarsals of 2-4; strongest of inverters
- Achilles tendon
- tendons of soleus,plantaris and gastrocnemius
- posterior tibial artery
- palpate posterior to medial malleolus (invert ankle)
- tarsal tunnel syndrome
- entrapment of tibial nerve deep to flexor retinaculum; results in cutaneous and motor dysfunction to muscles and skin innervated distally