The knee region Flashcards
Femur (anterior distal)
adductor tubercle at distal aspect of supracondylar ridge, medial and lateral condyles and epicondyles, lateral buttress wall, patellar surface
Distal femur (posterior view)
linea aspera, medial and lateral supracondylar rige, medial and lateral condyles and epicondyles, popliteal surface, adductor tubercle, intercondylar fossa
Proximal tibia- bony features
medial and lateral tibial condyles, tibial plateau, intercondylar eminence (medial and lateral tubercles)- associated with ACL, tibial tuberosity, anterior tibial crest
Proximal fibula- bony features
head and neck of fibula, apex of fibula, interosseous membrane
Proximal fibula- nerve
common fibular nerve/ common peroneal nerve- wrap around the neck of the fibula- this is sensitive to trauma
Patella bony features
sesamoid bones, within quadriceps tendon, patella tendon, triangular shaped, base superior, apex inferior, medial and lateral borders
knee joint classification
synovial joint, 3 articulations, protection of underlying tissue, modified bicondylar hinge joint- between femoral and tibial condyles, menisci attaching to tibial articular surfaces, 2 degrees of freedom
patellofemoral joint
synovial saddle joint, between patellar and femoral articular surfaces
femoral articular surfaces
convex antero posteriorly and medio-laterally, lateral condyle shorter and wider, medial condyle projects more distally, lateral condyle projects more anteriorly, covered in articular cartilage
tibial articular surfaces- shape
concave centrally, flatter peripherally covered with semilunar cartilage (menisci),
tibial articular surfaces- articular cartilage
medial side is C shaped (inner and thinner), lateral is an O shape (outer and stouter)
patella articular surfaces- posterior- articular facets
lateral and medial, odd- only comes into full articulation with the femoral surface on the distal femoral condyle on full flexion
what is the patella function
improves mechanical efficiency of the quadriceps muscle group by: increasing lever arm, increasing angular torque
What is the quadriceps angle (Q angle)
defined as angle between the quadriceps muscles (in particular RF), and the patellar tendon.
How is the Q angle measured
measured as angle between line from ASIS to centre patella and line from centre patella to tibial tuberosity
what does the Q angle represent
represents angle of quadriceps muscle force
What is the normal Q angle
in men- 13°, in women 18°, <13 or or >18° considered abnormal
what does a Q angle of over 18° mean
it may predispose to patellar lateralization- means patella is more lateral than it should be
what is the patellofemoral joint stability dependent on
patella position, lateral femoral buttress wall, ratio between VMO and VL- forms muscular tension, tightness of lateral retinaculum
what is VMO and VL
VMO- vastus medialis obliquus- stabilizes knee cap and keeps it in line with your bent knee
VL- vastus lateralis muscle
what is alta and baja patella position
alta- This is the condition where a person is born with a kneecap (patella) positioned higher in the front of the knee than the average
baja- is an abnormally low lying patella
what is the need for patella femoral joint stability
it is all designed to keep patella in the patella groove, if all of this goes wrong, then the patella can dislocate laterally
classification of the superior tibio- fibular joint
synovial plane joint
articular surfaces superior tibio- fibular joint
articular surfaces- head of fibula, tibial lateral condyle, capsule attached around joint margins
ligaments of the superior tibio- fibular joint
anterior and posterior ligaments of the fibular head
superior tibio- fibular joint- movements
small rotational movements during ankle DF and PF (gliding)
where does menisci sit
the top of the tibio femoral joint
shape of menisci
medial C shaped, lateral O shaped, medial narrower and thinner, medial less mobile and therefore more easily damaged
what are the 2 horns of menisci
anterior and posterior
what is the medial and lateral meniscus attached to
the medial meniscus is blended to capsule and medial collateral ligament, lateral menisci is not attached to lateral capsule or lateral collateral ligament, meaning it is less mobile and less commonly damaged
medial meniscus attachment- anterior horn
intercondylar area + ACL
transverse and coronary ligaments
medial meniscus attachment- posterior horn
PCL and posterior horn of lateral meniscus, blends with capsule and medial collateral ligament
lateral meniscus attachment- anterior horn
anterior intercondylar eminence posterior to ACL
sits inside posterior horn of medial meniscus
lateral meniscus attachment- posterior horn
posterior intercondylar area anterior to posterior
sits inside posterior horn of medial meniscus
meniscus function- stability
enhances tibio-femoral joint stability by deepening tibial articular surfaces
meniscus function- shock
act as shock absorber
meniscus function- changing shape
conforms to changing shape of femoral condyles during the knee movement
meniscus function- borders
outer borders- thick and vascular
inner borders- thin and avascular- less able to recover- become mechanical block
coronary ligaments
medial and lateral, attaches borders of meniscus to tibial plateau
knee joint capsule attachments- posteriorly
posterior femoral condyles and intercondylar fossa, posterior tibial condyles
knee joint capsule attachments- medially
blends with gastrocnemius and semimembranosus, medial articular margins femoral and tibial condyles, blends with medial collateral ligament
knee joint capsule attachments- laterally
lateral femur above popliteus, lateral tibial condyle, fibula head
knee joint capsule attachments- anteriorly
patella and retinaculum, capsule replaced by quadriceps tendon
synovial membrane knee joint capsule
synovial membrane projects in posteriorly to envelop but exclude cruciate ligaments (i.e. cruciate are extra synovial but intracapsular)
how is the postero- lateral capsule reinforced
it is reinforced by extension of semimembranosus tendon called the oblique popliteal ligaments and the ligaments of humphrey and wrisberg- strengthening in posterior capsule
anterior cruciate ligament attachments
anterior intercondylar area of tibia, runs posteriorly, laterally superiorly, posterior part of intercondylar area of lateral femur condyle
Posterior cruciate ligament attachment
posterior part of intercondylar area of tibia, runs anteriorly, medially and superiorly, lateral surface of medial femoral condyle
what is the action of the cruciate ligament
if femur is stationary ACL prevents tibia from translating anteriorly, PCL prevents posterior translation of the tibia on the femur
medial (tibial) collateral ligament
broad flat ligament, fan shaped, approx 10cm long, medial epicondyle of femur, medial proximal shaft of tibia, blends with knee joint capsule and medial meniscus
lateral (fibular) collateral ligament
strong rounded cord, proximal: lateral femoral epicondyle, distally: apex of head of fibula, no connection with the capsule of meniscus
collateral ligament function
MCL limits valgus movement of the tibia on the femur
LCL limits varus movement of the tibia on femur
Accessory movement of the knee complex- patello- femoral joint
longitudinal caudal excursion, med slide glide, lat side glide
Accessory movement of the knee complex- superior tibio fibular joint
AP glide, PA glide
Accessory movement of the knee complex- knee joint
AP glide, PA glide, med slide glide, lat slide glide
Accessory movement of the knee complex- patellofemoral medial and lateral slide glide
patient is supine with the knee slightly flexed. Medial glide- both hands press on the inferior and superior aspects of the medial patella and deliver a force to glide the patella in a lateral direction. (opposite for lateral)
Accessory movement of the knee complex- superior tibio fibular joint- AP glide
Often performed with the patient supine and the lower leg propped, reach maximal or near maximal extension. The proximal tibia is stabilized with one hand and the mobilising hand is placed on the distal femur. A posteriorly directed force is applied directly downward through the distal femur.
Accessory movement of the knee complex- superior tibio fibular joint- PA glide
patient lied in supine with the knee slightly flexed and a prop placed under the distal femur. The stabilizing hand is used to prop the distal femur and the mobilising hand is placed over the proximal tibia just below the tibial tuberosity. The mobilization is performed by a force perpendicular to the line of the tibia.
Tibial articular surfaces- condyles
medial tibial condyle projects further antero-posteriorly to accommodate medial femoral condyle, lateral condyle is short and thin, covered in articular cartilage
