Knee Anatomy And Biomechanics Flashcards by Wadhha Alajmi

What are the joints of the knee complex

Tibiofemoral joint

Patellofemoral joint

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Which joint is referred to as the “knee joint”?

Tibiofemoral joint

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The proximal and distal components of the Tibiofemoral joint ?

Proximal component: convex femoral condyles

Distal component: concave superior surface of the tibial plateau

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What is the joint type of Tibiofemoral joint

Hinge joint : convex on concave

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Motions of the Tibiofemoral joint and its degree of freedom DOF?

DOF = 2

Flexion
Extension
Medial rotation
Lateral rotation

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Resting position of Tibiofemoral joint and closed pack position ?

Resting position : 20 ° flexion

Closed packed position: full extension and lateral rotation

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Capsular pattern of Tibiofemoral joint

Flexion > extension

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Proximal and distal components of the patellofemoral joint

Proximal : convex femoral condyles

Distal: 5 concave facets of the patella

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Joint type of patellofemoral joint

Modified plane joint

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Motions of the patellofemoral joint and its degree of freedom

DOF = 2

Inferior glide with knee flexion
Superior glide with knee extension
Medial tilt
Lateral tilt

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The patella is the largest ______________ bone

Sesamoid

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How many facets does the patella have ?

5 facets

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Describe the patella’s shape

The Patella is an upside down triangle with its apex directed inferiorly

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The patella articulates superiorly with what structure ?

The Trochlea (distal articulating surface of femur)

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Understand patellar contact points during knee motion

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Explain the role and importance of the patellar compression force

where does the compression force occur exactly?

critical in providing the LAST 30 ° of knee extension (LEVERAGE)
occurs at quadriceps tendon attachment site

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The patellar compression force increases with which motion?

Knee flexion

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Compare the patellar compression force during different functional activities .

(Look at picture)
Notice that it is higher in squatting than walking due to more knee flexion

Describe the shape and mobility of the menisci and how well is their blood supply

What are the functions of the menisci ?

What happens if the menisci were removed ?

increase stress on cartilage of tibia
change the size and location of Tibiofemoral contact area

Characteristics of cruciate ligaments

Which is thicker ; PCL or ACL ?

PCL is 50% thicker than the ACL

Functions of the anterior cruciate ligament
(Hint: 4)

Functions of the posterior cruciate ligament

What are the collateral ligaments of the knee joint

Lateral collateral ligament Medial collateral ligament

Who are the knee extensors

Quadriceps femoris : - Rectus femoris - vastus medialis - vastus lateralis - vastus intermedius

Which muscle of the quadriceps femoris is a two joint muscle? What is its functions

Rectus femoris - knee extensor - hip flexor

Vastus medialis has two distinct parts

Vastus medialis longus (VML) Vastus medialis oblique (VMO) (NOTE: why? Probably due to clinical significance as VMO is larger, horizontal fibers, more effect on preventing patellar displacement, less effect for knee extension)

What are the knee flexors

Which knee flexors are two-joint muscles

The hamstrings : - biceps femoris - Semitendinosus - semimembranosus Gastrocnemius

What muscles are medial tibial rotators (at 90 ° of knee flexion)

Popliteus Semitendinosus Semimembranosus

What muscles are lateral tibial rotators ( at 90 ° of knee flexion)

Biceps femoris

What muscles are a part of the Pes Anserinus complex (Goosefoot)

A bursa is located interior to the conjoined tendons of the pes anserinus ; what is it called ?

Pes Anserine Bursa

What joints are involved in knee flexion and extension ?

Tibiofemoral Patellofemoral

What plane is knee flexion and extension and what is its axis of rotation

Sagittal plane

Arthokinematics of knee flexion

Posterior rolling and anterior gliding of femur on the tibia Inferior glide of patella on femur

Arthrokinematics of knee extension

Anterior rolling and posterior gliding of femur on tibia Superior glide of patella on femur

What is meant by screw-home mechanism

Basically: - during knee extension , tibial external rotation is needed to lock the knee - in order to flex the knee, we must first unlock it by performing tibial internal rotation then we may flex the knee

What is Q angle ?

Quadriceps angle The angle formed by the line of pull of the quadriceps (from ASIS to midpoint patella) and the line representing patellar tendon

Normal value for Q angle

Should fall between 12 ° - 20 ° On average: - Male: 13 ° - Female: 18 °

Factors affecting stability of the Tibiofemoral joint

Bony configuration Tension of the ligaments or other connective tissues Passive tension of muscles - Quad - Hams - Pes anserine

Factors affecting patella stability