KIN 191AAdvanced Assessment of Lower Extremity Injuries

KNEE/PATELLOFEMORAL ARTICULATION ANATOMY

INTRODUCTION

• ANATOMY– BONY STRUCTURES– ARTICULATIONS – LIGAMENTS– MENISCI– MUSCLES – BURSAE– NEUROANATOMY– VASCULAR ANATOMY

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BONY STRUCTURES

• Femur• Tibia• Patellar

• Fibular (Head)

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Femur• Distal end of the femur– Medial and lateral condyles

articulate with the tibia– Articular surface of medial

condyle is longer than lateral condyle

– Condyles share a common anterior surface, then diverge posteriorly, Intercondylar notch

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• Distal end of the femur– Anterior depression,

femoral trochlea• Patellar glides it with the

knee flexion/extension

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Video

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– Lateral epicondyle is wider and emanates from the femoral shaft at a less angle then the medial epicondyle

• Linea aspera– Posterior ridge along medial

and lateral lips

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• Adductor tubercle– Arises off the superior

crest of the medial epicondyle

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Tibia• Medial and lateral tibial

plateaus– Medial plateau: concave

in both the frontal and sagittal planes• 50% larger than L.

– Lateral plateau: concave in the frontal plane and convex in the sagittal plane

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MedialLateral

Anterior

Posterior

• Intercondylar eminence– Raised area between

the tibial plateaus– Match the femur’s

intercondylar notch

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• Tibial tuberosity– Infrapatellar tendon

attachment site

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Patellar

• Superior pole (Base), quadriceps femoris tendon attachment

• Inferior pole (Apex), infrapatellar tendon attachment

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L M

• Anteriorly protected/covered by prepatellar bursa

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Patellar• Lateral facet– Broader &– More concave than medial

facet• Medial facet– Shallower

• 3rd facet– Contact with the medial

femoral condyle in extreme flexion of the knee

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LateralMedial

Fibula

• Head– Muscular and ligamentous attachment site– Biceps femoris, soleus, peroneus longus– LCL, Arcuate ligament, popliteofibular ligament,

meniscofibular ligament

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Arcuate LigamentPopliteus

Popliteal Artery

ARTICULATIONS

• Tibiofemoral joint• Petellofemoral joint• Proximal tibiofibular joint

• Joint capsule

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Tibiofemoral Joint

• Double condyloid articulation• 2 degrees of freedom– Flexion and Extension– Internal and External rotation– Other movements: valgus and varus bending & anterior

and posterior glide (accessory motions)

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Joint Capsule

• Anteriorly,– Arises superior to the femoral condyles and

attaches distal to the tibial plateau

• Posteriorly– Inserts on the posterior margins of the femoral

condyles above the joint line and – Inferiorly, to the posterior tibial condyle

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• The strength of the capsule is reinforced by– Medial collateral ligament (MCL)– Patellofemoral ligament– Medial and lateral retinaculum

– Posterioly,• Oblique popliteal ligament and arcuate ligament

– Anteriorly,• Patellar tendon

– Muscles that cross the knee joint

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Arcuate (Popliteal) Ligament

Popliteus

Oblique Popliteal Ligament

Popliteus Fascia

• Synovial capsule– Lines the articular portions of the fibrous joint capsule– Synovium surrounds the articular condyles of the

femur and tibia medially, anteriorly and laterally– Invaginates anteriorly along the femur’s intercondylar

notch and tibia’s intercondylar eminences• Excluding the cruciate ligaments from the synovial

membrane

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LIGAMENTS

• Anterior Cruciate Ligament• Posterior Cruciate Ligament• Medial (Tibial) Collateral Ligament• Lateral (Fibular) Collateral Ligament• Arcuate Ligament Complex• Proximal Tibiofibular Ligaments

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Anterior Cruciate Ligament

• Arises from the anteromedial intercondylar eminance of the tibia, travels posterioly, and

• Passes lateral to the posterior cruciate ligament to insert on the medial wall of the lateral femoral condyle

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1. MCL2. Medial condyle of femur3. PCL4. Anterior meniscofemoral L.5. ACL6. Lateral condyle of femur7. Popliteus8. LCL

9. Biceps tendon10. Lateral condyle of tibia11. Lateral meniscus12. Medial meniscus13. Medial condyle of tibia14. Posterior meniscofemoral L.15. Capsule of superior tibiofibular joint16. Apex of head of fibula

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• ACL serves as a static stabilizer against– Femur from moving posteriorly during weight bearing

(anterior translation of the tibia on the femur)– Internal rotation of the tibia on the femur– External rotation of the tibia on the femur– Hyperextension of the tibiofemoral joint– Secondary restraint for valgus and varus stress with

collateral ligaments

– Anteromedial bundle• Taut when the knee is fully flexed

– Postolateral bundle• Taut when the knee is fully extended

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Video

Lateral View

Posterior Cruciate Ligament

• Arises from the posterior aspect of the tibia and takes a superior and anterior course, and

• Passing medially to the ACL, to attach on the lateral portion of the femur’s medial condyle

• The primary stabilizer of the knee– Stronger and wider than the ACL

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• Posterior cruciate ligament (PCL) serves as a static stabilizer against– Femur from moving anteriorly during weight

bearing (posterior translation of the tibia on the femur)

– External rotation of the tibia on the femur– Hyperextension of the tibiofemoral joint

– Anterolateral bundle• Taut when the knee is between 40-120 degrees of

flexion– Postomedial bundle• Taut when the knee is beyond 120 degrees of flexion

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Video

Medial View

Video

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Posterior View

Medial Collateral Ligament• Primarily medial stabilizer of the knee• Protect the knee against valgus forces– Also providing a secondary restraint against

external rotation

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• Formed by two layers– Deep layer is a thickening of the joint capsule– Attached to the medial meniscus– Separated from the deep layer by a bursa– Superficial layer arises from a broad band just

below the adductor tubercle to insert on a relatively narrow site 7 to 10 cm below the joint line

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– As a unit, the two layers of the MCL are tight in complete extension

– As the knee flexed to the mid range• Anterior fibers are taut

– In complete flexion• The posterior fibers are tight

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Video

Lateral Collateral Ligament• Primarily restraint against varus forces when

the knee is between full extension and 30 degrees of flexion– Provides secondary restraint against internal and

external rotation of the tibia and the femur

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• No attachment to the joint capsule or meniscus

• A cordlike structure arises from the lateral femoral epicondyle, sharing a common site of origin with the lateral joint capsule, and inserts on the proximal aspect of the fibular head

• Taut during knee extension but relaxed during flexion

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Video

Arcuate Ligament Complex

• Supports to the posterlateral joint capsule

• Arcuate ligament• Lateral collateral ligament• Oblique popliteal ligament• Popliteus tendon• Lateral head of gastrocnemius

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Arcuate LigamentPopliteus

Popliteal Artery LCL

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Arcuate (Popliteal) Ligament

Popliteus

Oblique Popliteal Ligament

Popliteus Fascia

LCL

Proximal Tibiofibular Ligaments

• Proximal anterior and posterior tibiofibular ligaments (proximal syndesmosis joint)

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MENISCI• Deepen the articular facets of the tibia– Increase the stability of the joint

• Improve lubrication for the articular surfaces• Cushion any stress placed on the knee joint• Maintain spacing between the femoral condyles

and tibial plateau

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Medial meniscusMedial meniscus– ““C” shaped fibrocartilage, largerC” shaped fibrocartilage, larger

Lateral meniscusLateral meniscus– ““O” shaped fibrocartilage, smallerO” shaped fibrocartilage, smaller

Meniscal Blood Supply

• Coronary ligament• Transverse ligament• Meniscofemoral ligaments– Anterior: ligament of Humphrey– Posterior: ligament of Wrisberg

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MUSCLES

• Anterior – Quadriceps

• Posterior – Hamstrings

• Medially – Pes anserine group

• Laterally – Illiotibial band

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Anterior Musculature

• Rectus femoris • Vastus lateralis• Vastus intermedius• Vastus medialis

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Rectus Femoris

• O: AIIS• I: Tibial tuberosity

via infrapatellar tendon

• N: Femoral• A: Knee extension,

hip flexion

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Vasti Muscles• O: VL – Greater trochanter,

upper ½ of linea aspera;

VI – Anterolateral upper 2/3 of femur, lower ½ of linea aspera

VM – Distal intertrochanteric line, medial linea

aspera• I: Tibial tuberosity via infrapatellar

tendon• N: Femoral• A: Knee extension

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Posterior Musculature

• Biceps femoris• Semimembranosus• Semitendinosus• Popliteus• (Gastrocnemius)

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Biceps Femoris• O: Long – ischial tuberosity; Short – lateral

linea aspera, upper 2/3 of supracondylar line

• I: Fibular head, lateral tibial plateau

• N: Long – tibial Short – common peroneal

• A: Knee flexion, Hip extension (long H.), Knee external rotation

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Semimembranosus

• O: Ischial tuberosity• I: Posteromedial of

medial tibial plateau• N: Tibial• A: Knee flexion, Hip

extension, Knee internal rotation

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Semitendinosus• O: Ischial tuberosity• I: Medial tibial flare (pes

anserine)• N: Tibial• A: Knee flexion,

Hip extension, Knee internal rotation

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Popliteus

• O: Lateral femoral condyle• I: Posteromedial tibia• N: Tibial• A: Knee internal rotation,

Knee flexion

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Pes Anserine Muscles

• Sartorius (most anterior)• Gracilis (middle)• Semitendinosus (most posterior)

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Sartorius

• O: ASIS• I: Anteromedial tibial

flare (pes anserine)• N: Femoral• A: Hip flexion,

Hip abduction,Hip external rotationKnee flexion

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Gracilis

• O: Symphysis pubis, inferior ramus of pubic bone

• I: Anteromedial tibial flare (pes anserine)

• N: Obturator• A: Hip adduction,

Hip flexion,Knee flexion

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Iliotibial Band/TFL

• O: Anterior superior iliac crest

• I: Anterolateral tibia at Gerdy’s tubercle

• N: Superior gluteal• A: Hip flexion,

Hip abduction,Hip internal rotation

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Popliteal Fossa• Borders– Superomedial:

semimembranosus– Superolateral: biceps femoris– Inferomedial: medial gastroc

head– Inferolateral: lateral gastroc

head• Contents– Popliteal artery and vein– Tibal and common peroneal

nerves

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BURSAE

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NEUROANATOMY

• Tibial nerve• Common peroneal nerve• Femoral nerve

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