7 - Knee Joint Flashcards
Where is the anterior inferior iliac spine?
Label this saggital view of the knee joint.
Label this diagram of the femur.
- Slight medial angulation so knee closer to body’s centre of gravity
Label this diagram of the distal femur and state which leg it comes from?
- Right side
- Trochlear groove articulates with patella
- Medial condyle larger as bears more weight
What is the difference in prominences between the femoral condyles and why?
- Lateral condyle more prominent to prevent patella displacement laterally during tracking
- Those with flatter femoral condyle more prone to dislocation and instability of patella
What arises from the epicondyles of the femur?
Collateral ligaments
What arises from the intercondylar groove (femur), and where do they insert?
- Cruciate ligaments
- ACL: Attaches to medial aspect of lateral condyle
- PCL: Attaches to lateral aspect of medial condyle
PAM’s APPLES
What is the anatomy of the patella?
- Held in trochlear groove by quadriceps tendon superiorly, and patella ligament inferiorly to the tibial tuberosity
What are the three main functions of the patella?
- Stabilise and reduce friction on femoral condyles
- Protect anterior knee from physical trauma
- Extension of leg by attaching quadriceps to the tibia so acts as a fulcrum. Increase mechanical efficiency of the muscle
Label this diagram of the proximal tibia.
What is the intercondylar eminence the main attachement for and what do the intercondylar tubercles articulate with?
- Attachement of cruciate ligaments and the menisci of the tibia
- Articulate with the intercondylar fossa
What are the borders of the tibia shaft?
Prism-shaped
- Anterior: proximal aspect marked by tibial tuberosity and is palpable all the way down
- Posterior: marked by ridge of bone known as soleal line which extends inferomediall
- Lateral (Interosseous): Interosseous membrane arises here
How do the inferior portions of the leg bones articulate with the tarsals?
- Malleolus
What are the three articulations of the fibula and what is the anatomy of the fibula?
- Proximal tibiofibular joint (lateral condyle of tibia)
- Distal tibiofibular joint (fibular notch)
- Ankle joint (talus bone of foot)
Has three surfaces and lateral malleolus can be palpated at ankle joint
What is the issue with proximal fibula fractures?
Common peroneal nerve winds around posterior and lateral surfaces of the fibula neck so vulnurable to damage
What type of joint is the knee joint and what two articulations make the joint?
- Hinge synovial joint
- Tibiofemoral and patellofemoral
- All within the same joint capsule
What is the blood and nerve supply to the knee joint?
Blood: Genicular anastomoses supplies by genicular branches of femoral and popliteal arteries
Nerve: Femoral, Tibial and Common Peroneal
What is the stability of the knee joint like and how is stability improved?
- Unstable due to high motion allowed
- Deepened articular surface by menisci
- Ligaments
- Joint capsule
What is the function of the menisci of the knee?
- Deepen articular surface, increasing joint stability
- Shock absorber by increasing surface area to dissipate forces over
- Avascular by adulthood so difficult to repair
How are the menisci of the knee attached in terms of ligaments and label this diagram of them.
- Peripheral rims attached to tibia and joint capsule by coronary ligaments
- Menisci attached to each other by transverse ligament
- Posterior meniscofemoral ligament stabilises posterior horn of lateral meniscus by attaching to medial femoral condyle
- Menisci attach at both ends at the intercondylar area. Thicker at periphery than centrally
What are the ligaments involved in the knee joint?
Oblique popliteal ligament comes from semimembranosis and strengthens the back of the knee
What do the cruciate ligaments prevent?
PCL: prevents posterior tibia dislocation on the femur. main stabiliser when standing
ACL: prevents anterior translation and medial rotation of the tibia in relation the femur
What is the joint capsule of the knee joint like?
- Surrounds the sides and posteriorly but deficient anteriorly to allow supra-patellar bursa
- Strengthened at sides by vastus lateralis and medialis muscles
- Strengthened by oblique popliteal ligament posteriorly (continuation of semimembranosus tendon)
What do the collateral ligaments resist?
Medial: resists valgus angulation of tibia. Weaker and more likely to tear, taking meniscus with it. (wide flat ligament)
Lateral: resist varus angulation of tibia (thin round ligament). Reenforced by iliotibial tract
Label the bursa of the knee.
- Reduce friction and allow free movement. Filled with synovial fluid
- Semimembranosus between semimembranosus and medial head of gastrocnemius
- Subsartorial between common insertion of pes anserinus tendons and medial tibial condyle
How does the knee lock, and what is the purpose of this?
- When fully extended, foot on the floor, 5 degree medial rotation of femoral condyles on tibial plateau, Cruciate ligaments tighten so whole limb is weight bearing
- Thigh and leg muscles can relax without losing knee stability
- To unlock, popliteus contracts rotating femur laterally
What are the movements possible in the knee joint and what muscles bring this movement about?
- Extension: Quadriceps femoris which insert onto tibial tuberosity
- Flexion: Hamstrings, assisted by gracillus, sartorius, popliteus, plantaris and gastrocnemius
- Lateral rotation (f_lexed knee_): biceps femoris
- Medial rotation (flexed knee): semimem and ten, gracilis, sartorius and popliteus
What is the Q angle, and what resists the lateral displacement by pull of the angle?
- Angle between line of pull of quadriceps and patellar ligament means during extension patella tries to displace laterally
- Deep trochlear groove and VMO contraction resist this
- Posteriorly, hamstrings, gastrocnemius, popliteus
- Laterally, IT band
What are the muscles of the anterior thigh compartment, what are they innervated by, and what is the blood supply?
Innervation: Femoral nerve (except psoas L1-L3 anterior rami)
Blood Supply: Branches of femoral artery called profunda femoris and lateral/medial femoral circumflex arteries
Movement: Flex hip and/or extend knee
What is the origin and insertion of the iliopsoas and what movement does it cause?
- Psoas: transverse processes of T12-L5 and lateral margins of intervertebral discs, onto lesser trochanter
- Iliacus: Iliac fossa onto lesser trochanter
Movement: iliopsoas flexes hip, assists lateral rotation of femur
What is the origin and insertion of the quadriceps femoris, and what movement do they cause?
Where do sartorius and pectineus originate and insert, and what movement do they have on the lower limb?
Pectineal line on superior pubic ramus!
What is the pes aserinus?
Say Grace before Tea
What muscles are in the medial compartment of the thigh and what are they innervated by and the blood supply?
Exception: Hamstring part of adductor magnus is innervated by tibial part of sciatic nerve
Where do each of the medial thigh muscles originate and insert, and what movement do they cause?
Label this cross section of the thigh.
What are the borders of the femoral triangle and label this diagram?
- Superior: Inguinal ligament
- Lateral: Medial border of sartorius
- Medial: Medial border of adductor longus
- Roof: Fascia Lata
- Base: Pectineus, iliopsoas, adductor longus
SAIL
What is adductor brevis a landmark for?
Anterior and posterior divisions of obturator nerve
What is contained in the femoral sheath?
- Femoral vein
- Femoral artery
- Femoral canal
How do you find the femoral artery on the surface?
MIPA
- Mid inguinal point midway between ASIS and symphis pubis just inferior to inguinal ligament
What does the femoral canal contain, what are it’s borders and where is it anatomically?
- Most medial part of femoral sheath
- Pectineal ligament posterior border
- Femoral ring closed by connective tissue (femoral septum) which is pierces by lymphatic vessels
- Contains: Lymph vessels draining deep inguinal lymph nodes, lacunar node, empty space, loose CT
- Allows distension of femoral vein or distension due to increased intra abdominal pressure
What is the adductor canal and what are it’s borders?
- Narrow 15cm tunnel from apex of femoral traingle to adductor hiatus.
- Acts as passageway for superficial femoral artery, femoral vein, nerve to vastus medialis and saphenous nerve between anterior thigh and posterior leg
Where is the popliteal artery and vein?
The femoral artery and vein once they pass the adductior hiatus into popliteal fossa
What is the map of the femoral nerve, what branches come off it and what skin does it supply?
- Passes out of psoas major on inferior lateral border, passing behind fascia iliaca to mid point of inguinal ligament
- Passes behind ligament to enter thigh and splits into anterior posterior 4cm below ligament
What is the map of the obturator nerve?
- Emerges from medial border of psoas major running posterior to common illiac arteries and goes through obturator canal
- Anterior division pierces fascia lata to supply middle part of medial thigh
- Posterior division goes through obturator externus
What are the branches of the common femoral artery as it travels down the leg.
Profunda femoris branching in femoral triangle, which then branches into 3 too
What is the blood supply for the gluteal, medial and posterior region of the lower limb?
- Gluteal = superior and inferior gluteal arteries from internal iliac artery via greater sciatic foramen
- Medial = obturator artery from internal iliac artery. enters medial via obturator canal
What are the different deep veins draining the upper lower limb?
Obturator vein: drains medial compartment of thigh and becomes internal iliac vein
S/I gluteal veins: Drain into internal iliac vein
Femoral veins: Popliteal vein until through adductor hiatus then femoral vein. Femoral vein through adductor canal. Profunda femoris vein via perforating veins drains from thigh. Femoral becomes external iliac vein as passes through inguinal ligament
What are the superficial veins of the lower limb?
- Run in subcutaneous tissue: great and small saphenous veins
What are the deep and superficial lymphatic vessels of the leg?
Superficial
Medial: Close to great saphenous vein and drain into inferior group of superficial inguinal lymph nodes in triangle
Lateral: Follow small saphenous vein to drain into popliteal lymph nodes which drain into deep inguinal nodes, or cross to join medial group of vessels
Deep
- Fewer in number and accompany deep arteries. Anterior tibial, posterior tibeal and peroneal. Enter popliteal lymph nodes
