Knee Comp Flashcards
What bones make up the knee joint?
The distal femur, the proximal tibia, and the patella.
What is the popliteal surface?
The posterior surface of the femur proximal to the intercondyler fossa.
As the joint flexes how does the patella move?
It moves distal and Lateral with increasing knee flexion.
What is a valgus deformity?
A narrowing of the lateral compartment of the knee joint.
What is a narrowing of the medial compartment of the knee called?
A varus deformity.
How is the location of the fibular head affected by tube angle?
Excessive cephalic angulation will demonstrate the fibular head more than 1.25cm distal to the tibial plateau.
What determines the CR angle on an AP knee projection?
The height of the ASIS. If the pt has a pelvic height of less than 18 cm you angle 5 caudad, 19-24 straight ray, 25cm and up 5 cephalic.
Where are the posterior and anterior suprapatellar fat pads located?
Anterior to the femur, and separated by the suprapatellar bursa.
What degree of flexion will best demonstrate an air fluid level on a lateral knee?
10-15
How does body habitus effect CR angle on lateral knee projections?
Wide pelvis, short femur length will require more angle.
If the adductor tubercle is seen posterior to the lateral condyle what positioning error has occurred?
The knee was internally rotated. Patella too far from the IR.
Do you need an angle on your tube for cross table lateral projections?
No, if the knee and hip joints are aligned no angle is required.
What positioning methods can be used to image the IC fossa?
The Hombland method-PA Axial projection.
The Beclere method-AP Axial Projection.
What are the 4 major ligaments of the knee joint?
Medial collateral ligament (MCL)
Lateral collateral ligament (LCL)
Anterior cruciate ligament (ACL)
Posterior cruciate ligament (PCL)
What are the joint classifications of the knee?
Femorotibial- hinge, bicondylar
Femoropatellar- saddle
Proximal tibiofibular- sliding, gliding
Chondromalacia patellea
Runners knee. A softening of the cartilage under the patella.
Ewing’s sarcoma
Occurs in young adults. Bone stratified new bone growth. Results in an onion peel look the the bone.
Exocytosis
Benign lesion caused by over production of bone at a joint. The tumour grows parallel to the bone away from the joint until the epiphyseal plates fuse.
Osgood-schatters disease
Inflammation of the bone and cartilage of the proximal anterior tibia. Caused when the patellar tendon pulls part of the tibial tuberosity off the bone.
