2 ObjectivesName 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.
8 Anterior. Patella articulates with the femur. Sagittal section thru kneeTibia:Condyles (plateaus)Tibial tuberosityTibia and fibulaare united by aninterosseousMembrane.[Proximal anddistal tibio-fibularjts]The fibula is not part of the knee joint.Head ofFibulaPatella articulateswith the femur.interosseous membrane
9 During the entirerange of kneeflexion, the patellaonly articulateswith the femur.KNEE:Modified hinge jt.-flexion / extension(some rotation)
10 Superior view of tibial surface. Tibial CondylesTibial CondylesMedial and lateral articularsurfaces, separated by anintercondylar eminence.Medial and lateral Menisci:Fibrocartilage shock-absorbersthat sit on surface of tibialcondyles and deepen thearticular surface.Anterior and posteriorCruciate ligaments (ACL, PCL):-hold femur and tibia together-stabilize knee jointlateral articular surfacemedial articular surfaceintercondylar eminencelateral meniscusPCLmedial meniscusACL
11 tibia at their ends (horns), and outer periphery (coronary lig.) Medial and lateralfemoral condyleshave same shape ascorrespondingtibial condyles:Medial – elongatedLateral – circularMeniscii:Each is attached totibia at their ends (horns),and outer periphery(coronary lig.)Femur
12 Type & Articular Surfaces Knee joint is formed of:Three bones.Three articulations.Femoro-tibial articulation: between the 2 femoral condyles & upper surfaces of the 2 tibial condyles (Type: synovial, modified hinge).Femoro-patellar articulation: between posterior surface of patella & patellar surface of femur (Type: synovial, plane).
13 CapsuleDeficient anteriorly & is replaced by: quadriceps femoris tendon, patella & ligamentum patellae.Possesses 2 openings: one (posteriorly) for popliteus tendon & one (anteriorly) for communication with suprapatellar bursa.
14 MenisciThey are 2 C-shaped plates of fibro-cartilage attached by anterior & posterior horns, to the articular surface of tibia.FUNCTION:Deepen articular surfaces of tibial condyles.Serve as cushions between tibia & femur.
15 Lateral meniscus Medial SizesmallLargeShapeCircularOvalOuter borderseparated from lateral collateral ligament by popliteal tendon.attached to the capsule & medial collateral ligament.MobilityMore mobileLess mobileLiablity for injuryLess liableMore liable
16 The synovial membrane 1- lines the capsule, 2- attaches to the margins of the articular surfaces,3- attaches to the peripheral edges of the menisci (semilunar cartilages),4- covers the front of the ant cruciate ligament, and the back of posterior cruciate ligament.5- communicates with:- suprapatellar bursa,- popliteus bursa,- semimembranosus burse,- gastrocnemius bursa.
17 Bursae Related to KneeSuprapatellar bursa: between femur & quadriceps tendon, communicates with synovial membrane of knee jointPrepatellar bursa: between patella & skin.Deep infrapatellar bursa: between tibia & ligamentum patella.Subcutaneous infrapatellar bursa: between tibial tuberosity & skin.Popliteal bursa: between popliteus tendon & capsule, communicates with synovial membrane of knee joint.12534
18 Working on hands-and-knees: Housemaid knee bursa subcutaneus prepatellar bursitis.
19 Ligaments: 4 Extracapsular 312Ligamentum patellae (patellar ligament): from patella to tibial tuberosity.Medial (tibial) collateral ligament: from medial epicondyle of femur to upper part of medial surface of tibia (firmly attached to medial meniscus).Lateral (fibular) collateral ligament: from lateral epicondyle of femur to head of fibula (separated from lateral meniscus by popliteus tendon).Oblique popliteal ligament: extension of semimembranosus tendon.
20 Ligaments: 2 Intracapsular The Cruciate Ligaments Two in number, situated in the middle of the joint.They are called cruciate because they cross each otherHave received the names anterior and posterior, from the position of their attachments to the tibia.
21 Anterior cruciate ligament: Extends from anterior part of intercondylar area of tibia to posterior part of lateral condyle of femur.Prevents posterior displacement of femur on tibia.Prevents hyperextension.Weaker of the two, slack when knee is flexed & tightens in extension.Posterior cruciate ligament:Extends from posterior part of intercondylar area of tibia to anterior part of medial condyle of femur.Tightens during flexion of knee jointPrevents anterior displacement of femur on tibia.
22 Stabilization of the medial knee: Tibial collateral ligament. A flat strap whichis attached to themedial aspect oftibia and medialfemoral epicondyle.Its deeper fibres areattached to themedial meniscus.tibial collateral ligamentJoint capsuleRetinacularfibresPes anserinus (goose’s foot): Common insertion ofSartorius, gracilis, semitendinosus
23 Movements FLEXION: EXTENSION: Mainly by hamstring muscles: biceps femoris , semitendinosus & semimembranosus.Assisted by sartorius , gracilis & popliteus.EXTENSION:Quadriceps femoris.ACTIVE ROTATION (PERFORMED WHEN KNEE IS FLEXED):A) MEDIAL ROTATION:Mainly by semitendinosus & semimembranosus.Assisted by sartorius & gracilis.B) LATERAL ROTATION:Biceps femoris.
24 Movements INACTIVE (DEPENDANT) ROTATION: A) LOCKING OF KNEE: Lateral rotation of tibia, at the end of extensionResults mainly by tension of anterior cruciate ligament.In locked knee, all ligaments become tight.B) UNLOCKING OF KNEE:Medial rotation of tibia, at the beginning of flexion.Performed by popliteus to relax ligaments & allow easy flexion.
25 Anterior knee in extension Fibrous capsule of theKNEE (anterior):Stabilized by:Extensor Retinacula- Derived from insertionsof vastus lateralis andvastis medialis into patellaand into sides of patellarligament.VastuslateralisVastus medialisextensor retinaculaPatellarLigament
26 Posterior knee in extension Fibrous capsule of theKNEE (posterior):Thickened by ligaments:-Arcuate popliteal ligament(arching over popliteus muscle)-Oblique popliteal ligament(from tendon of insertion ofsemimembranosus m.)arcuate politeal ligamentTendon ofSemimembranosusoblique popliteal ligamentPopliteus
27 Structures inside the Knee joint: 1- The 2 menisci (semilunar cartilages).2- The cruciate ligaments.3- Popliteus tendon.Nerve supply of theknee joint:Femoral, obturator, tibial, andcommon pernoneal nerves.Arterial supply ofFrom the anastomosis around knee.
28 Q-Angle The Q-angle is the angle formed by : 1-a line from the anterior superior iliac spine to the middle of the patella ,and2-a line from the middle of the patella to the tibial tuberosity.Males typically have Q-angles between 10 to 14o,females between 15-17o.