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Knee joint and Muscles of Leg Dr. Sama ul Haque Name and identify the bony features of the tibia and fibula. Know the type and formation of knee joint. Explain the stability factors of the knee joint. Identify the muscles that act at the knee joint. Know the locking and unlocking mechanism of the knee joint. Understand the functions of the Popliteus and Iliotiabial tract. Identify the neurovasculature behind the knee (popliteal fossa) and in the leg. Enlist the contents of the muscular compartments of the leg. Identify the muscles of the leg in terms of their origin, insertion, nerve supply and actions. Enlist the muscles causing plantar flexion, dorsiflexion, eversion, inversion, flexion of digits and extension of digits. Anterior. Sagittal section thru knee Head of Fibula Tibia: Condyles Tibial tuberosity Tibia and fibula are united by an interosseous Membrane. [Proximal and distal tibio-fibular joints] interosseous membrane The fibula is not part of the knee joint. Patella articulates with the femur. During the entire range of knee flexion, the patella only articulates with the femur. KNEE. Modified hinge jt. -flexion / extension (some rotation) Superior view of tibial surface. Tibial Condyles Tibial Condyles lateral articular surface medial articular surface Medial and lateral articular surfaces, separated by an intercondylar eminence. Medial and lateral Meniscii: intercondylar eminence lateral meniscus PCL medial meniscus Fibrocartilage shock-absorbers that sit on surface of tibial condyles and deepen the articular surface. Anterior and posterior Cruciate ligaments (ACL, PCL): -hold femur and tibia together -stabilize knee joint ACL Femur Medial and lateral femoral condyles have same shape as corresponding tibial condyles: Medial – elongated Lateral – circular Meniscii: Each is attached to tibia at their ends (horns). Anterior Cruciate Ligament: - Weaker of the two, slack when knee is flexed & tightens in extension. - Prevents hyperextension. Posterior Cruciate Ligament: - Tightens during flexion of knee joint Stabilization of the medial knee: Tibial collateral ligament. Joint capsule Retinacular fibres tibial collateral ligament A flat strap which is attached to the medial aspect of tibia and medial femoral epicondyle. Its deeper fibres are attached to the medial meniscus. Pes anserinus: Common insertion of Sartorius, gracilis, semitendinosus Ilio-tibial band fibular collateral ligament Biceps femoris Head of fibula Stabilization of the lateral knee: Fibular collateral ligament - a cord which is attached to the head of the fibula and the lateral epicondyle of the femur. *Its deep fibers are not attached to the meniscus. » » » » Remember the 3 C’s: -cartilage -cruciates -collaterals Unhappy triad - common associated injury to: ACL (anterior cruciate ligament) MCL (Medial / tibial collateral ligament) medial meniscus Anterior knee in extension Vastus lateralis Vastus medialis Fibrous capsule of the KNEE (anterior): Stabilized by: extensor retinacula Patellar Ligament Extensor Retinacula - Derived from insertions of vastus lateralis and vastis medialis into patella and into sides of patellar ligament. Posterior knee in extension Fibrous capsule of the KNEE (posterior): arcuate popliteal ligament Tendon of Semimembranosus oblique popliteal ligament Thickened by ligaments: -Arcuate popliteal ligament (arching over popliteus muscle) -Oblique popliteal ligament Popliteus (from tendon of insertion of semimembranosus m.) Bursae of Knee Joint: Sagittal section shows: suprapatellar bursa prepatellar bursa infrapatellar bursae - Suprapatellar bursa (extension of synovium under tendon of quadriceps femoris) Subcutaneous bursae: - Prepatellar, - Infrapatellar (2): (superficial & deep to patellar ligament). Popliteal Fossa Popliteal fossa Diamond-shaped region Posterior to knee -semimembranosus / semitendinosus -biceps femoris -medial & lateral heads of gastrocnemius. Contents: -popliteal vessels (from femoral vessels) -Tibial and Common fibular (peroneal) divisions of the sciatic nerve. Superficial: -Small saphenous vein draining into popliteal vein Muscles that act on the knee (modified hinge joint): Main movement = flexion / extension Flexion – mainly hamstrings (+ Sartorius, gracilis, gastrocnemius) Extension – mainly quadriceps (+ tensor fascia lata) Rotation (possible when the knee is partially flexed, or in the final stage of extension): [here defined as rotation of tibia with respect to the femur] Medial rotation – semitendinosus, semimembranosus popliteus (extended knee) Lateral rotation – biceps femoris LEG. Tibia and fibula: -held together by an interosseus membrane. interosseous membrane Medial malleolus Lateral malleolus -anterior border of tibia is subcutaneus from the tibial condyles to its distal end. [Shin] -only the distal ¼ of fibula is subcutaneus The distal ends are held together to form the proximal articular surface of ankle. Each ends subcutaneusly as a Malleolus (medial – tibial and lateral - fibular). Proximal and distal tibio-fibular joints Mid-shaft cross-section of leg: Fascial compartments: Functional compartments. -anterior -lateral -posterior (superficial & deep) anterior compartment (dorsiflexion, extension of digits) lateral Compartment (eversion) deep posterior compartment (plantarflexion) superficial posterior compartment (inversion, flexion of digits) Plantarflexion / dorsiflexion: (ankle joint) Inversion / eversion: Complex twisting Flexion / extension: (digits) movement at transverse tarsal and subtalar joints. [inter-tarsal joints] Anterior compartment of leg: -tibialis anterior -extensor hallucis longus -extensor digitorum longus (fibularis tertius) tibialis anterior extensor digitorum longus Hallux = big toe [hallucis] extensor hallucis longus extensor retinaculum All supplied by the deep fibular (peroneal) nerve. Tendons are bound down by extensor retinaculum as they cross the ankle jt. Function: -dorsiflexion (ankle) -extension (digits) -inversion Common Fibular n. Superficial Fibular n. extensor digitorum longus Deep dissection Anterior view: Deep Fibular n. Tibialis Anterior Note vulnerability of common fibular nerve as it winds around the neck of fibula. extensor hallucis longus DROP FOOT?????? Lateral compartment of leg: - Fibularis (peroneus) longus - Fibularis (peroneus) brevis Fibularis longus -both supplied by the superficial fibular (peroneal) nerve. Tendons are bound down by fibular retinaculum as they pass behind the lateral malleolus. Functions: - eversion - plantarflexion peroneal retinaculum Fibularis brevis Fibularis tertius FIBULARIS=PERONEUS Posterior compartment of leg: Superficial medial & lateral heads of gastrocnemius gastrocnemius Insert into calcaneus (heel) Function –plantar flexion Achilles tendon (calcaneal tendon) Innervated by Tibial nerve. Deeper dissection of superficial posterior compartment: - medial & lateral heads of gastrocnemius - soleus plantaris - (plantaris) soleus Common tendon: Calcaneal (achilles) tendon - insert into calcaneus (heel) Function – plantar flexion Innervated by Tibial nerve. Posterior (deep) compartment of leg: -Tibialis posterior -Flexor digitorum longus -Flexor hallucis longus flexor digitorum longus tibialis posterior flexor retinaculum flexor hallucis longus Tendons are bound down by flexor retinaculum as they pass into foot behind the medial malleolus. Functions: -plantarflexion -flexion -inversion Innervated by Tibial nerve. Blood supply to the lower limb: popliteal a. posterior tibial a. anterior tibial a. fibular artery Thigh: -Femoral artery and branches: (profunda, medial & lateral circumflex) Behind knee: -Popliteal artery Leg: -divides into anterior and posterior tibial arteries. to supply these compartments. The posterior tibial artery gives off the fibular (peroneal) artery to supply the lateral compartment. Cutaneus innervation of thigh and leg: Anterior Posterior Anterior, lateral, medial thigh ( lumbar plexus). - branches of femoral n. - lateral femoral cutaneous n.) Post. femoral cutaneous n. Posterior thigh – from sacral plexus. Anteromedial leg – branch of femoral n. (Saphenous nerve). saphenous nerve L4 Posterolateral leg – from Sciatic n. (Sural nerve). Anterior leg: - From Sciatic n. (Superficial fibular n.) sural nerve S1 Superficial drainage of the lower limb Varicose veins Great Saphenous vein: Drains into femoral vein in femoral triangle Small Saphenous vein: Drains into popliteal vein Thank you