anatomy: knee & leg

The femoral condyles are separated posteriorly and inferiorly by

intercondylar fossa

In the patellar surface, condyles merge ___, forming ___, which articulates with the patella.

anteriorly; depression

Three surfaces and borders of the tibia

medial, lateral/interosseous, posterior

The distal end of the tibia extends into the

medial malleolus

Tibia articulations (select all that apply)

- condyles of the femur superiorly

- talus inferiorly

- fibula via interosseous membrane

Gerdy's tubercle provides the distal attachment for the ___, adding ___ to the knee joint.

IT band; stability

Gerdy's tubercle

The distal end of the fibula becomes the

lateral malleolus

The fibula provides a distal attachment for ___ muscle and proximal attachment for ___ muscles.

1; 8

The patella is a

large triangular sesamoid bone

The patella is formed in the tendon of the ___ ____ birth.

quads; after

The subcutaneous anteiror surface of the patella is

convex

Function of patella

provides a mechanical advantage to the quads in extending the leg at the knee

The base of the patella is ___ and the apex is ___.

superior; inferior

The knee is a ___ joint.

hinge type synovial

Knee articulations (select all that apply)

- two femorotibial articulations (between femoral and tibial condyles)

- one patellofemoral articulation between the patella and femur

Patellofemoral joint type

planar/gliding joint

The stability of the knee joint depends on (select all that apply)

the strength and actions of the surrounding muscles and their tendons (distal fibers of vastus medialis & lateralis), the ligaments that connect the femur and tibia

The knee joint capsule is made up of an

external fibrous capsule and internal synovial membrane

5 major ligaments of the knee joint (select all that apply)

patellar, fibular collateral, tibial collateral, oblique popliteal, arcuate popliteal

The oblique popliteal ligament is formed from

semimembranosus

Medial and lateral patellar retinacula

aponeurotic expansions of the vastus medialis and lateralis and overlying deep fascia, making up the joint capsule of the knee on each side of patella

Function of the medial and lateral patellar retinacula

maintains alignment of the patella relative to the patellar articular surface of the femur

Collateral ligaments of the knee

FCL, TCL

The collateral ligaments of the knee are taut in ___, allowing ___ while standing.

full extension; stability

The collateral ligaments of the knee are slack in ___, allowing ___ of the knee.

flexion; rotation

The fibular collateral ligament is a ___ ligament.

cord-like extracapsular

Fibular collateral ligament

The fibular collateral ligament limits

genu varus

The tibial collateral ligament is a ___ ligament.

strong capsular

Tibial collateral ligament

connects medial femoral and medial tibial condyle

The tibial collateral ligament limits

genu valgus

The oblique popliteal ligament reinforces the joint capsule ___.

posteriorly

Which ligament(s) of the knee are extracapsular

fibular collateral ligament, oblique popliteal ligament, arcuate popliteal ligament,

Oblique popliteal ligament

runs posterior to medial tibial condyle and passes superolaterally towards lateral femoral condyle

The arcuate popliteal ligament strengthens the joint capsule

posterolaterally

The intra-articular knee has (select all that apply)

cruciate ligaments, menisci, tendon of the popliteus is also intra-articular during part of its course

The cruciate ligaments ___ within the joint capsule of the joint but ___ the synovial cavity.

crisscross; outside

During medial rotation of the tibia on the femur

cruciate ligaments wind around each other

During lateral rotation of the tibia on the femur

cruciate ligaments unwind

The ___ orientation of the cruciate ligaments causes one or both ligaments to ___ in every position

oblique; tense

Cruciate ligaments maintain contact with the ______ during ___ of the knee.

femur and tibial; flexion

The ACL is the ___ of the two cruciate ligaments.

weaker

The ACL extends

superiorly, posteriorly, laterally

The ACL limits (select all that apply)

- posterior rolling of femoral condyles on tibial plateau during flexion

- posterior displacement of femur on tibia

- hyperextension of the knee joint

Intercondylar fossa

depression between the condyles

Patellar surface

articulates with patella

Tibial plateau

- flat articular surface

- articulates with femur

- separated by intercondylar eminence

Fibular facet

on proximal tibia; articulation site for head of fibula

The ___ is important for the stability of the ankle joint.

fibula

The fibula attaches to the tibia via

tibiofibular syndesmosis

The fibula is a ___ joint.

syndesmotic

Which ligament(s) of the knee are capsular

tibial collateral ligament

Arcuate popliteal ligament

runs from posterior aspect of fibular head and superomedially to over the tendon of popliteus

Anterior cruciate ligament

runs from anterior intercondylar tibia, posterior to attachment of medial meniscus to posterior part of medial side of lateral condyle of femur

Posterior cruiciate ligament

runs from posterior intercondylar area and attaches at anterior lateral surface of medial condyle

Which muscle performs medial and lateral rotation of the tibia

hamstrings

ACL attachments

anterior intercondylar area of tibia, posterior to attachment of medial meniscus to posterior part of medial side of lateral condyle of femur

The PCL is the ___ of the two cruciate ligaments.

stronger

The PCL limits (select all that apply)

- anterior rolling of the femur on the tibial plateau during extension, converting it to spin

- anterior displacement of femur on tibia or posterior displacement of tibia on femur

- hyperflexion of knee joint

In the weight-bearing flexed knee, the ___ is the main stabilizing factor for the femur (e.g. when walking downhill).

PCL

When the joint is flexed at a right angle, the tibia cannot be pulled anteriorly because it is held by the ___.

ACL

The PCL runs

superior, anterior, medial

The ACL runs

superior, lateral, anterior, posterior

Function of the menisci

deepens the surface, shock absorption

The menisci are attached via

coronary ligaments

The menisci are made up of

fibrocartilage on the articular surface of the tibia

The medial meniscus is ___ and broader ___ than ___.

C-shaped; posteriorly; anteriorly

The lateral meniscus is ___ and ___ than the medial meniscus.

nearly circular; smaller

The lateral meniscus is ___ movable than the medial meniscus.

more freely

The lateral meniscus is an attachment site for the

popliteus

The lateral meniscus attaches to the ___ and ___ via the ___.

PCL; medial femoral condyle; posterior meniscofemoral ligament

Movements of the knee joint

flexion, extension, some rotation when flexed

Muscles that extend the knee

quadriceps femoris

Muscles that flex the knee

hamstrings, sartorius, gracillis, gastroch, popliteus

Muscles that medially rotate the knee

semitendinosus, semimembranosus, gracillis, sartorius, popliteus

Muscles that laterally rotate the knee

biceps femoris

Suprapatellar bursa

anterior bursae underneath the quad tendon

Prepatellar and infrapatellar bursae

between skin and patella/patellar tendon ot allow smooth movement

Deep infrapatellar bursa

underneath patellar tendon

Posterior bursae include

popliteus, gastrocnemius, semimembranosus, anserine

Popliteus bursa

deep to popliteus tendon

Gastrochnemius bursa

deep to medial and lateral heads of gastrochnemius

Semimembranosus bursa

deep to the semimembranosus

Anserine bursa

deep to the attachment of sartorius, gracilis, and semitendinosus

The plica is formed by a

sharp margin of synovial membrane

Inflammation of the plica can cause

synovitis and erosion of cartilage

The plica can lose ___ and become more fibrous with wear and inflammation.

elasticity

Superolateral border of the popliteal fossa

biceps femoris

superomedial border of popliteal fossa

semimembranosus

Inferolateral & inferomedial borders of the popliteal fossa

lateral and medial heads of the gastrocnemius (respectively)

Deep superior boundaries of the popliteal fossa

medial and lateral supracondylar lines of the femur

Deep inferior boundary of the popliteal fossa

soleal line of the tibia

Deep floor (anterior wall) of the popliteal fossa

popliteal surface of the femur superiorly and posterior aspect of the joint capsule of the knee joint centrally

Nerves of the popliteal fossa

- common fibular nerve

- inferior branches of posterior cutaneous nerve of thigh

- tibial nerve

- sural nerve

The common fibular nerve gives off

sural communicating branch

The inferior branches of the posterior cutaneous nerve of thigh supplies

skin over the popliteal fossa

Tibial nerve gives branches to

leg musculature and medial sural cutaneous nerve

The sural nerve is made up of

medial sural cutaneous nerve joined by sural communicating branch of fibular nerve

The popliteal artery ends at the ___ border of popliteus by dividing into the _______.

inferior; anterior and posterior tibial arteries