The Knee Joint Flashcards
What are the 2 articulations of the knee joint?
Tibiofemoral (Between distal femur and proximal tibia)
Patellofemoral (Articulation with the patella)
What type of fluid is found around the knee joint?
Synovial fluid
Why does the knee joint have greater stability when locked/fully extended?
Greater articulating surface
(Femoral condyles have a greater surface area of contact with the tibial plateau
What anatomical movement happens to the femur when the knee joint locks and unlocks?
Slight medial rotation to lock it
Laterally rotates to unlock it
What is the advantage of the knee locking?
Prevents muscle fatigue as constant muscle contraction is not required if bones lock together
What is the knee joint supported by?
Intracapsular ligaments (ACL and PCL)
Extracapsular ligaments (Lateral Collateral and Medial Collateral ligaments)
Menisci
Quadriceps
Joint Capsule
What are Menisci?
Fibrocartilage found on the superior surface of the Tibial plateau
What is the shape of the lateral meniscus?
Round
What is the shape of the Medial meniscus?
C-Shaped
What ligament is the medial meniscus connected to?
Medial collateral ligament
What is the function of the Menisci?
SHOCK absorption
Increase congruity of the joint (SA of contact between femoral condyles and tibial plateau)
What is Valgus strain?
Strain that tries to push the knee joint MEDIALLY
(Lateral to medial)
What is a way to remember what ValGUS strain is?
A GUST of wind makes a woman bring her KNEES TOGETHER while she holds down her dress
What is Varus strain?
When the knee is trying to be forced LATERALLY
(MEDIAL to LATERAL)
What is an easy way to remember what Varus strain is?
Opposite of ValGUS
Think Rickets = bowed legs
Rickets has an R in it
VaRus
Where is the Anterior Cruciate ligament located?
Inserts Anteriorly on the intercondylar eminence of Tibia and intercondylar fossa of the femur
What is the function of the Anterior Cruciate ligament?
Prevents Tibia moving anteriorly relative to the femur
Prevents Femur moving posteriorly relative to the tibia
Where is the Posterior Cruciate Ligament (PCL) in the joint?
Inserts/attaches posteriorly on the tibia at the intercondylar eminence
What is the function of the Posterior Cruciate Ligament?
Prevents Tibia moving posteriorly relative to the femur
Prevents Femur moving anteriorly relative to the Tibia
What are Bursae?
Fluid filled sacs
What is the function of Bursae?
Increase fluidity of the joint reducing friction of the knee
Where is the superficial/subcutaneous preptellar bursa located?
Anterior to patella
Where is Subsatorial bursa located?
Associated with peas anserinus
Where is the Semimembranosus bursa located?
Posterior to the knee joint
What is the joint capsule composed of?
Outer thin fibrous membrane
Inner synovial membrane
What is the function of the joint capsule?
Provide rigidity and stability of joint
Which muscles strengthen the joint capsule medially and the laterally?
Medial Strength = Vastus medialis
Lateral strength = Vastus Lateralis
What ligaments strengthen the joints capsule medially and laterally?
The collateral ligaments
Medially = Medial collateral ligament
Laterally = Lateral collateral ligament
What are the 4 muscles that make up the quadriceps femoris of the ANTERIOR compartment of the thigh?
Rectus femoris
Vastus intermedius
Vastus lateralis
Vastus medialis
Where is Vastus intermedius located?
Underneath Rectus femoris
Where do all the 4 quadriceps femoris muscles insert?
Quadriceps tendon (which leads to patella which leads to patellar ligament)
What functions do the muscels of quadriceps femoris (Rectus fem, Vastus medialis, intermedius and lateralis) have?
Knee extension (All join to patella at quadriceps tendon)
Hip Flexion (Only Rectus femoris)
Why does Rectus Femoris contribute to knee extension and hip Flexion? (Origin and insertion)
Origin = Anterior Inferior Iliac Spine (AIIS) of Hip
Insertion = Quadriceps Tendon
What is the origin of Rectus femoris?
Anterior Inferior Iliac spine
What is the origin of Vastus lateralis?
Greater trochanter + linea aspera
What is the origin of Vastus intermedius?
Anterior and lateral surfaces of femoral shaft
What is the origin of Vastus medialis?
Intratrochanteric line + medial lip of linea aspera
What is the other non quadriceps muscle in the anterior thigh?
Sartorius
What is the function of Sartorius?
Knee Flexion
(Synergist so isn’t only muscle that does Flexion)
What is the origin of Sartorius?
Anterior Superior Iliac Spine (ASIS)
Where is the insertion of Sartorius?
The Pes anserinus
Region on media side of the tibia
What are all the muscles of the ANTERIOR part of the thigh innervated by?
Femoral nerve
What is the function of the hamstrings of the posterior thigh in terms of the knee?
Knee Flexion
What are the 4 hamstring muscles?
Biceps femoris (long head)
Biceps femoris (short head)
Semitendinosus
Semimembranosus
What is the origin of biceps femoris (long head) , Semimembranosus and semitendinosus?
Ischial tuberosity
What is the origin of biceps femoris (short head)?
Linea aspera
Where does the biceps femoris insert?
Fibula
What nerve innervates all 4 of the hamstring muscles?
Sciatic nerve
Which nerve innervates the short head of Biceps femoris?
Common fibular divison of the sciatic nerve
What nerve innervates the long head of biceps femoris, Semimembranosus and semitendinosus?
Tibial division of the sciatic nerve
Where does semitendinosus insert?
Pes anserinus
What medial thigh muscle is important in knee felxion?
Gracillis
What is the origin of Gracilis?
Pubic tubercle
What is the insertion of Gracilis?
Pes anserinus
What nerve innervates all of the medial thigh muscles?
Obturator nerve
What is the function of the popliteal/ popliteus muscle?
Slight lateral rotation of the knee to UNLOCK the knee
What innervates the popliteus?
Tibial nerve
What is the blood supply to the knee joint?
Femoral arteries and popliteal arteries join up and branch forming GENICULAR Arteries
What does anastomoses mean?
Joining up of vessels
What is the nerve supply to the knee joint?
Many due to Hiltons law:
-Femoral
-Obturator
-Tibial division of sciatic
-Common fibular division of sciatic
What is Hiltons law?
Nerves that supply muscles that cross a joint will innervate the joint and the above skin
Where is the femoral triangle found?
Superior anterior potion of the thigh
The top of the thigh
What is the superior border of the femoral triangle ?
Inguinal ligament
What is the lateral border of the femoral triangle?
Sartorius
What is the medial border of the femoral triangle?
Adductor longus
What muscles make up the triangle border of the femoral triangle?
Inguinal ligament
Sartorius
Adductor longus
What forms the roof oof the femoral triangle?
Fascia lata
What 2 muscles form the floor of the femoral triangle ?
Pectineus
Ilopsoas
How can the femoral pulse be located?
Midpoint between the diagonal of the ASIS (anterior superior iliac spine) and the pubic symphysis
What is the adductor hiatus?
The gap between the adductor Magnus and the tibia
What Pneumonic can be remembered to remember the neurovascular bundle of the femoral triangle from LATERAL to MEDIAL?
NAVEL or NAVY
What does NAVEL stand for?
Nerve (Femoral)
Artery (Femoral)
Vein (Femoral)
Empty space (Femoral canal)
Lymphatics
What does NAVY stand for?
Nerve
Artery
Vein
Y front (the shape of the groin so you can remember the direction)
What is contained in the femoral canal/empty space of the femoral triangle?
Lymphatics
What is the femoral sheath?
Fascia that surrounds the femoral artery veins and femoral canal
What is the problem with the femoral canal?
Contents of abdomen ay move down the femoral canal forming a femoral hernia
