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ABOVE KNEE AMPUTATION. ARTHROSCOPY. KNEE JOINT. Block 14 GNK 483. Anatomy. Classification Bones Capsule Ligaments Synovial membrane Cruciate ligaments Menisci Nerve supply. Blood supply Relationships Bursae Movements. Classification. Synovial hinge joint
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KNEE JOINT Block 14 GNK 483
Anatomy • Classification • Bones • Capsule • Ligaments • Synovial membrane • Cruciate ligaments • Menisci • Nerve supply • Blood supply • Relationships • Bursae • Movements
Classification • Synovial hinge joint • Medially & laterally: femur & tibia (hinge and rotation) • Intermediate: Femur & patella (gliding joint
Capsule • Absent anteriorly • Synovial membrane protrudes to form the bursa beneath the tendon of quadriceps femoris • It is anteriorly reinforced by the tendon of quadriceps femoris, the patella and the patella retinacula
Capsule • Inferiorly, the capsule is fixed to the margins of the tibia, except where the tendon of popliteus passes • The capsule is reinforced on both sides by the expansions of vastus lateralis and medialis, as well as behind by the oblique popliteal ligament from the insertion of semimembranosus
Ligaments5 extracapsular • Patellar ligaments – quadriceps reflex L2,3,4 • Lateral collateral ligament • Medial collateral ligament • Oblique popliteal ligament • is an expansion from the insertion of semimembranosus • Arcuate popliteal ligament • Y-shaped ligament posterior that bridges the tendon of popliteus
Ligaments4 intracapsular • Synovial membrane • Cruciate ligaments • Menisci • Tendon of popliteus
Synovial Membrane • Infrapatellar fold is a reflexion from the posterior surface of the patella-forms a fold to the intercondylar fossa • The synovial membrane from the posterior part of the capsule is reflected around the front of the cruciate ligaments-they are therefore intracapsular but extrasynovial
Cruciate LigamentsExtrasynovial • Anterior • Taut in extension • Prevents post displacement of femur on tibia • Prevents hyperextension of the knee
Cruciate LigamentsExtrasynovial • Posterior • Stronger • Taut during flexion • Prevents ant displacement of femur on tibia • Prevents hyperflexion of the knee
Menisci - General • Medial & lateral • C-shaped • Fibrous cartilage • Upper surface concave • Outer margins thicker, convex,attached to capsule • Inner margins thinner, concave,free border • Transverse ligament extends between the 2 ant parts of the menisci
Menisci • Medial meniscus • Semicircular (oval) • Wider at back than in front • Attached to medial collateral ligament • Most commonly injured
Menisci • Lateral meniscus • Almost circular • Even width front and back • Separated from lateral collateral ligament via popliteal tendon
Nerve Supply • Br of femoral n to vastus medialis • Obturator n (the br passes with the femoral a thro the add hiatus to popliteus fossa • Sciatic n
Blood Supply • Genicular anatomosis formed by brrs of popliteal a • Middle genicular a pierces the capsule & supplies cruciate lig’s, synovial mem, outer margins of menisci
Relations • Anterior femoris quadriceps femoris & bursa • Posterior • popliteal fossa+contents, popliteal a+v, tibial+c.peroneal nn • Lateral • Biceps femoris, lateral collateral ligament, tendon of popliteus • Medial • Sartorius, gracilis,medial coll lig,semitendinosus
Bursae – Anterior (4) • Suprapatellar • Beneath quadriceps femoris • Prepatellar • Housemaids knee • Superficial infrapatellar • Betw skin & patellar ligament • Clergyman’s knee • Deep infrapatellar • Betw patellar lig & tibia
Bursae – Posterior (2) • Beneath popliteus • Beneath semimembranosus
Bursae – Posterior (2) • Others: Biceps femoris Lateral head of gastrocnemius Medial head of gastrocnemius Anserine bursa below insertion of: • Sartorius • Gracilis • semitendinosus
Movements • Flexion • hamstrings+sartorius,gracilis,gastroc • Extension • quadriceps femoris+medial rotation • Rotation • Passive: screw home mechanism • Active: medially in a flexed knee (SarGrTen) laterally via Biceps femoris