Posterior Aspect of Thigh & Knee Joint 2019-20 PDF

POSTERIOR ASPECT OF TIGH & KNEE JOINT  Semitendinosus & Semimembranosus  Origin- ischial tuberosity  insertion○ medial surface of superior part of tibia (semitendinosus) ○ Posterior part of medial condyle of tibia (Semimembranosus)     Innervation-tibial division of sciatic nerve Extend tigh...

POSTERIOR ASPECT OF TIGH & KNEE JOINT  Semitendinosus & Semimembranosus  Origin- ischial tuberosity  insertion○ medial surface of superior part of tibia (semitendinosus) ○ Posterior part of medial condyle of tibia (Semimembranosus)     Innervation-tibial division of sciatic nerve Extend tigh Flex leg and rotate medially When tigh and leg are flexed they can extend trunk Biceps femoris Origin Long head-ischial tuberosity Short head-linea aspera and lateral supracondylar line of femur Insertion-lateral side of head of fibula; tendon split at this site by fibular collateral ligament of knee Innervation long head tibial n. Short head common fibular n Flex leg and laterally rotate; extend tigh Knee Joint Anatomy-Bones  Bones  Femur ○ Medial/lateral femoral condyles articulate w/ tibia  Tibia ○ Tibial plateau is flat-articulates w/ femoral condyles  Fibula ○ Articulates w/ tibia  Patella ○ Sesamoid bone protects anterior joint ○ Enclosed in quadriceps/patellar tendon General Information Knee joint is the largest and most complicated joint. It consists of: 1-TIBIOFEMORAL JOINT Structurally a hinge joint Considered as a condylar type of synovial joint 2-PATELLOFEMORAL JOINT Saddle joint 3-SUPERIOR TIBIOFIBULAR JOINT ARTICULATING BONES 1. Lateral and medial articulations between the tibial condyles and their cartilaginous menisci and the corresponding femoral condyles. ARTICULATING BONES 2. Intermediate articulation between the patella and femur. THE FEMORAL CONDYLES The medial extends further forwards. The lateral is more oval. The condyles are convex from front to back. TIBIAL CONDYLES The medial is oval. The lateral is round. The articular surfaces are covered with hyaline cartilage. Articular capsule Thin and deficient in some areas Attaches superiorly proximal to articular margins of condyles and also intercondylar fossa posteriorly Deficient on lateral condyle to allow popliteus tendon Inferiorly fibrous capsule attaches to articular margin of tibia Patella and patellar ligament serve as capsule anteriorly Ligaments Intracapsular Ligaments Cruciate ligaments Menisci Anatomy-Meniscus Meniscus Medial and lateral Fibrocartilaginous discs Thicker on outside than inside (poor blood supply) Lie on top of tibial plateau Increase stability Make condyles fit better Shock absorbers Anatomy-Ligaments ACL-anterior cruciate ligament Runs from anterior tibia to posterior femur Prevents anterior displacement of tibia on fixed femur Prevents femur from moving posterior during weight bearing Stabilizes tibia against excessive internal rotation Ligaments PCL-posterior cruciate ligament Runs from posterior tibia to anterior femur Prevents posterior translation of tibia on fixed femur Prevents femur from moving anterior during weight bearing Both ACL and PCL “cross” or wrap around each other—taut when in extension and looser when in flexion The ACL prevents the femur from sliding posteriorly on the tibia or the tibia from sliding anteriorly on the femur. F E M U R PATELLA The PCL prevents the femur from sliding anteriorly on the tibia or the tibia from sliding posteriorly on the femur. T I B I A The PCL prevents the tibia from sliding posteriorly on the femur. Posterior Anterior Ligaments Extracapsular ligaments Patellar ligament Fibular (lateral) collateral ligament Tibial (medial) collateral ligament Oblique popliteal ligament Arcuate popliteal ligament LIGAMENTS Ligamentum Patellae It is the intermediate part of the tendon of quadriceps femoris. Ligaments MCL-medial collateral ligament Attaches on the medial femoral epicondyle & anteromedial tibia Thickened portion of joint capsule Two parts-superficial and deep Deep portion attaches to medial meniscus Stabilizes against valgus stress applied to lateral aspect of joint capsule Ligaments LCL-lateral collateral ligament Attaches to lateral femoral epicondyle and head of fibula Stabilizes against varus stress when force is applied to medial aspect of joint Both the MCL and LCL are tightest during full extension of knee and relaxed during flexion Ligaments OBLIQUE POPLITEAL An expansion of the Semimembranosus. It strengthens the capsule posteriorly. Ligaments Arcuate popliteal ligament strengthens the fibrous capsule posteriorly Arises posterior aspect of the fibular head Passes superomedially over tendon of popliteus and spreads over posterior surface of joint General Information Lateral stabilization: Biceps Gastrocnemius (lateral head) Iliotibial tract Fibular collateral ligament Medial stabilization: Sartorius Gracilis Gastrocnemius (medial head) Semitendinosus Semimembranosus Tibial collateral ligament (From Netter’s Atlas of Human Anatomy, 2014) SKIN Cutaneous innervation Infrapatellar branch of the saphenous nerve Peripatellar plexus (From https://thekneeresource.com. SKIN The arterial supply of the skin covering the knee: Genicular branches of the popliteal artery Descending genicular branch of the femoral artery Anterior recurrent branch of the anterior tibial artery Small contributions from the arteries to vastus medialis and the hamstrings (From Gray’s Anatomy, 2008)