Anatomy: Knee Flashcards
1
Q
Frontal Plane Analysis: Normal Alignment
A
- Alignment described in “varus” or “valgus”
- Measurements using Anatomical or Mechanical axis
- Anatomical Axis
- Femur: oblique
- TIbia: Vertical
- Valgus (~ 5 degrees)
- Varus: knees out: joint opens laterally; compresses forces on medial side
- Valgus: knees in: joint opens medially; compresses forces on lateral side.
2
Q
Abnormal LE Alignment: Frontal Plane: Genu Valgum
A
- Defined as medial TF angle > 195 degrees
- Consequences:
- Increased compressive forces lateral condyles
- Increased tensile forces medial structures
3
Q
Abnormal LE Alignment: Frontal Plane: Genu Varum
A
- Defined as medial TF angle <180 degrees
- Consequences:
- Increased compressive forces on medial condyles
- Increased tensile forces on lateral structures
4
Q
Sagittal Plane Analysis: Normal Anatomical Position
A
- LOG passes slightly anterior to knee joint
- Normal TF angle= 180 degrees
- Little to no muscle activity required in static posture
- Support provided by posterior structures.
5
Q
Abnormal LE Alignment: Sagittal Plane: Genu Recurvatum
A
- LOG falls substantially anterior to knee joint
- Posterior joint capsule and related structures under considerable stress
- May result in adaptive lengthening
- Increased compressive forces anterior aspect of femoral condyles and tibial plateaus
6
Q
Proximal TIbia: Osteology
A
- Medial condyle
- Lateral Condyle
- Intercondylar eminence: ACL, PCL, and menisci attach here
- TIbial plateau
- Tibial Tuberosity
- Tibial Crest: bony prominence down the anterior femur
7
Q
Proximal Fibula: Osteology
A
Fibular Head: biceps femoris, lateral collateral ligament
Neck of the Fibula: Common peroneal n.
8
Q
Distal Femur: Anterior View
A
- Medial Condyle
- medial epicondyle
- Lateral Condyle
- lateral epicondyle
- Adductor tubercle: where you the adductor Magnus attaches
9
Q
Femoral Condyles: Tibiofemoral Articular Surfaces
A
- Medial condyle is larger and projects farther distally
- Covered w/ articular cartilage
- Intercondylar (trochlear) groove: where the patella lies
- Intercondylar fossa: where the cruciate ligaments go through
10
Q
Distal Femur: Posterior View
A
- Linea Aspera
- Supracondylar Lines
11
Q
TIbiofemoral Joint Classification
A
- Diarthrodial (synovial)
- Bicondylar
- Biaxial
- Compound: multiple articulations meaning that there is a medial and lateral surface
- Complex: disc Fibrocartilage
- Functions primarily as a hinge joint (flexion and extension)
- Some rotation in the transverse plane
- Closed packed position is also called the screw-home position
12
Q
Members of Knee Joint
A
- Femoral condyles
- Intervening menisci
- Tibial plateaus and condyles
13
Q
Tibial Condyles: Proximal Tibia
A
- Medial Tibial condyle or plateau
- Is longer in the anteroposterior direction
- The oval-shaped medial tibial plateau is larger (~50%)
- Lateral tibial condyle or plateau
- Is shorter (smaller) in the anteroposterior direction
- More circular in shape
- The articular cartilage is thicker than that of the medial tibial plateau
14
Q
Tibiofemoral Osteokinematics
A
- Normal knee flexion= 140 degrees
- Normal knee extension= 0 degrees
- Impact of 2 joint muscles:
- with hip extended, knee flexion ROM may be limited to 120 degrees
- with hip flexed, knee flexion ROM may be increased to 150-160 degrees
15
Q
Tibiofemoral Osteokinematics: Functional ROM (Sagittal Plane)
A
- Gait requires 60 degrees knee flexion
- Stair climbing requires 80 degrees knee flexion
- Sitting in a chair requires at least 90 degrees knee flexion
16
Q
Tibiofemoral Arthrokinematics
A
- Tibial articular surfaces are concave
- Femoral articular surfaces are convex
- Open chain: concave on convex
- Tibia on femur; anterior roll and anterior glide
- Closed chain: Convex on concave
- Femur on Tibia; posterior roll and anterior glide
- 0-25 degrees of CC flexion causes posterior roll of femur on a fixed tibia
- After 25 degrees posterior roll is accompanied by an anterior glide of femur
17
Q
Locking Mechanism of the Knee (Screw-Home Mechanism) OKC
A
- Open Kinetic Chain (OKC) in a non-weight bearing position
- 30 degrees from full extension
- Lateral tibial condyle completes arthrokinematics first
- As extension continues the medial tibial condyle arthrokinematics continues
- Results in external rotation of the tibia
- Brings joint into CPP
18
Q
Locking Mechanism of the Knee (Screw-Home Mechanism) CKC
A
- Closed Kinetic Chain (CKC) in a weight-bearing position
- 30 degrees from full extension
- LFC completes arthrokinematics first because it is smaller than the MFC
- As extension continues the MFC arthrokinematics continues
- This results in internal rotation of the femur
- Brings joint into the CPP (majority of the supporting ligaments to become taut)
- Coming out of CC the femur will externally rotate as the knee flexes
19
Q
Unlocking the Knee: TIbiofemoral Arthrokinematics
A
Open Chain
- First 30 degrees of flexion
- Medial tibial condyle moves first
- Followed by lateral condyle which causes IR of tibia
- Brings knee into OPP
Closed Chain
- First 30 degrees of flexion - Medial femoral condyle moves first - Followed by lateral condyle which causes ER of femur - Brings knee into OPP
20
Q
Capsular Kinesiology: Tibiofemoral Joint
A
- Closed Packed Position: full knee ext with full ER
- Open Packed Position: 20-30 degrees of knee flexion
- Capsular pattern: greater limitation in flexion than extension
21
Q
Patella
A
- Sesamoid bone (largest in body)
- Triangular with apex at inferior pole
- Posteriorly its surface should be smooth
- By holding the quadriceps further forward, adds a great deal to effectiveness of quadriceps pull
- proximal aspect: base
- Distal aspect: apex or inferior pole
22
Q
Patellofemoral Joint Classification
A
- Diarthrodial
- Planar
- Defined by the shape of the patellar surface of the femoral condyles
23
Q
Members of Patellofemoral Joint
A
- Posterior surface of patella and anterior surface of femoral condyles
- Least congruent joint of the body
24
Q
Patellar articular surfaces on the femoral condyles
A
- Intercondylar (trochlear groove)
- The lateral patellar surface is larger
- The medial patellar surface is smaller
25
Q
Patella: Articulating (posterior) Surface
A
- A vertical ridge corresponds to trochlear groove and divides posterior surface into 2 facets
- In general has asymmetrical facets
- Lateral articular facet
- Medial articular facet
- Odd facet is located medial to the medial facet
26
Q
Patella Tracking: Tilt
A
Axis is superior/inferior
- With knee extended, patella rests in slight lateral tilt
- medial tilt occurs from 0-30 degrees of flexion and > 100 degrees
- Lateral tilt occurs between 30-100 degrees of flexion
27
Q
Patella Tracking: Rotation
A
Axis is anterior/posterior
- Medial rotation occurs when inferior pole moves medially with tibial IR
- Lateral rotation occurs when inferior pole moves laterally with tibial ER
28
Q
Patella Tracking: Patella Glide
A
- Medial glide occurs with knee flexion
- Lateral glide occurs with extension
-This is a translation instead of rotation so movement doesn’t occur along an axis.
29
Q
Importance of the Patella
A
- Considered an anatomic pulley
- Alters angle of pull for patella tendon (quadriceps muscle)
JRF increase as knee flexion increases:
-Ex: stair climbing: PF JRF = 3.3 x body weight; squats PF JRF= 7.8 x body weight
30
Q
Capsular Kinesiology: Patellofemoral Joint
A
- CPP- full flexion
- OPP- full extension
- Capsular pattern - n/a due to being a planar joint
31
Q
Non-muscular support of Knee Joint Complex
A
- Tibiofemoral and patellofemoral joints are highly incongruent
- Tibiofemoral- shallow articular of tibia on convex femur
- Patellofemoral-shallow articular facets of patella
32
Q
Knee Joint Capsule
A
Encloses the tibiofemoral and patellofemoral joints
- In general it is large and lax
- It is grossly composed of an external or superficial fibrous layer and a thinner internal synovial membrane
33
Q
Fibrous Capsule
A
- Attaches to posterior aspects of femoral and tibial condyles, and runs across the intercondylar notch
- Attaches medially and laterally along border of femur and tibia
- Anteriorly blends with tendons of VL and VM (aka medial and lateral patellar retinaculi), and attaches to edges of patella.
- Cruciate ligaments are in the capsule but outside the synovial
34
Q
Fibrous Capsule: Retinaculum
A
- Lateral retinaculum reinforced by ITB
- Retinaculi further reinforced by patellofemoral & patellotibial ligaments
- MPFL: medial patella femoral ligament. An important stabilizer of the patella
35
Q
Synovial Capsule
A
- Posteriorly attaches to condyles of tibia and femur
- Posteriorly reflects off the fibrous capsule and loops forward following the contours of the condyles
- So, intercondylar notch and eminence enclosed by fibrous layer but outside synovial space
36
Q
Synovial Membrane:
A
- Posteriorly-invaginates anteriorly to
- Follow femoral intercondylar notch between the femoral condyles.
- Adheres to the anterior and sides of the ACL and PCL ligaments
- ACL and PCL are intracapsular and extrasynovial
- Posterolaterally the synovial lining passes between the popliteus muscle and the lateral femoral condyle
37
Q
Synovial Capsule-Anteriorly
A
- Continues w/ fibrous layer attaching to patellar borders.
- Again differentiates from fibrous layer proximal to patella.
- Forms a large pocket that extends proximally a few cm between femur and quadriceps muscle
- This is known as the suprapatellar pouch and essential for full movement of patella and knee
38
Q
Patella Tendon (Ligament)
A
- Characteristics
- Continuous with quadriceps tendon
- Strong and thick
- Merges with fibrous capsule via retinaculum
- Attachments: inferior/anterior patella to tibial tuberosity
- Associated structures
- infrapatellar fat pad
- Bursa
39
Q
Medial Collateral Ligament
A
- Attachments: medial femoral condyle to medial tibial condyle and medial meniscus
- Superficial
- Deep
- Function: Checks against valgus force and taut in extension
- Taut in ER of tibia in OC
- Taut in IR of femur and tibia in CC
- Taut in Extension
- Blends in with capsule not really able to isolate and palpate like LCL
40
Q
Lateral Collateral Ligament
A
- Extracapsular and extrasynovial
- Attachment: lateral femoral condyle to lateral fibular head
- Checks against varus force
- Taut in extension
- Taut in IR of tibia in OC
- Taut in ER of femur and tibia in CC
41
Q
Anterior Cruciate Ligament
A
- Intracapsular and Extrasynovial
- Attachments: intercondylar region of tibia to posteromedial lateral femoral condyle
- Mainly prevents anterior translation of tibia on femur
- Anteromedial bundle-taut in full flexion and extension
- Posterolateral bundle-taut in full extension
- All taut in tibial and femoral internal rotation in CC
42
Q
Posterior Cruciate Ligament
A
- Attachments: posterior tibia intercondylar region to anteromedial aspect of medial femoral condyle
- Shorter, thicker and stronger than ACL
- Mainly checks against posterior displacement of tibia on femur
- Taut in full flexion, full extension and IR of femur.
43
Q
Accessory Ligaments of the Knee
A
Oblique Popliteal Ligament
-Located b/t semimembranosus tendon and LFC
-Taut in full extension
Arcuate Popliteal Ligament
-Originates from Fibular head then divides (“Y”)
Reinforcements of the Posterior Capsule
44
Q
Menisci
A
-Fibrocartilage
-Located on articular surface of tibia
-lateral covers more than medial
Attachments:
-Centrally: small ligaments attaching to horns
-Peripherally: coronary ligament
Deepens the tibial plateaus
-In sagittal section they are wedge-shaped such that they are thicker on the periphery and thinner centrally
45
Q
Menisci-Function
A
- Protect against compressive and rotational forces (shock absorption)
- Increase contact area between tibia and femur
- Stabilization
- Innervation-aneural
- Vascularity:
- red zone: good blood zone good potential to heal
- Red/white zone: ok potential to heal
- White zone: nope no healing
46
Q
Medial Meniscus
A
- “C” shaped
- Broader posteriorly than anteriorly
- More anchored than lateral
- Increased risk of injury
- Attaches to deep portion of MCL
- Less (tibial) coverage area leads to increased contact area between femur and tibia.
- Medial tears are more common than lateral
47
Q
Lateral Meniscus:
A
- More crescent shaped
- Smaller and more mobile than medial meniscus
- Separated from LCL by popliteus tendon
- Covers more tibial area, which decreases contact area between tibia and femur
48
Q
Anterior and Posterior Horns
A
- Each horn is firmly attached to the tibia plateau below
- Meniscal motion on the tibia is limited by multiple attachments to surrounding structures
- The medial meniscus has greater ligamentous and capsular restraints, limiting translation to a greater extent than the lateral meniscus
49
Q
Common Meniscal Attachments
A
- Coronary Ligaments: Attaches periphery of meniscus to tibial plateau
- Transverse Tibial Ligaments: attaches anterior horns of medial and lateral meniscus
50
Q
Unique Medial Meniscal attachments
A
- The deep fibers of the medial collateral ligament (MCL)
- The anterior horn of the medial meniscus is attached to the anterior cruciate ligament (ACL)
- The posterior horn of the medial meniscus is attached to the posterior cruciate ligament (PCL)
- Through capsular connections the semimembranosus
51
Q
Unique Lateral Meniscal Attachments
A
- The meniscofemoral ligament connects lateral meniscus to the PCL and the medial femoral condyle
- The tendon of the popliteus muscle through capsular attachments
- helps to control the mobility
- separates the lateral meniscus from the lateral collateral ligament (LCL)
52
Q
Bursae of the Knee
A
- General functions of bursa-lubrication, nutrition
- Communicating bursa are invaginations of the synovial membrane of the joint
- the suprapatellar bursa
- popliteus bursa
53
Q
Bursae of the Knee: Non-Communicating bursa
A
- Prepatellar Bursa-located b/t skin and anterior aspect of patella
- Subcutaneous Infrapatellar bursa located b/t skin and tibial tuberosity
- Deep infrapatellar bursa located between patellar tendon and anterior aspect of infra patellar fat pad (superficial to tibial tuberosity)
- Pes Anserine Bursa
- Gastrocnemius Bursa
- Communicating means that it’s a continuum of the synovial.
54
Q
Fat Pad
A
- Deep Infrapatella Fat Pad
- Highly Innervated
- Good Vasculartization
55
Q
Retinaculum
A
- Extension of fibrous layer of knee joint
- Retinaculum
- Medial
- Lateral
56
Q
Plica
A
- Superior Band
- Medial band
- Most prominent
- Inferior Band
- Can be small or large and can become thickened and a source of pain
57
Q
Iliotibial Band (ITB)
A
- Tendon of TFl
- Thickening of fascia lata
- Attaches to lateral tibia at Gerdy’s tubercle
- Also has fibers blending to lateral retinaculum and patella, therefore fibrous layer of joint
- Function
- > 30 degrees flexion
- < 30 degrees flexion
58
Q
Popliteal Artery
A
Continuation of Femoral artery passes through the adductor hiatus distally
59
Q
Popliteal Fossa
A
- Borders
- Posteriorly-gastrocnemius (2 heads)
- Floor- popliteus m. and femur
- Superolateral- biceps femoris m.
- Superomedial- semimembranosus and semitendinosus mm.
- Contents: popliteal artery and vein, tibial and common peroneal nerve
