Knee

 Intercondylar notch
Indications for imaging
? Loose bodies in the joint capsule in the intercondylar notch of femur, fractures of the tibial spines

 

Anatomy  Demonstrated
 The femoral intercondylar notch, tibial spines, femoral condyle surfaces.


Lt Knee Intercondylar notch anatomy
Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London

 

Basic Patient Position
Patient Prone, The patient lies prone on the table with the long axis of the leg aligned to the long axis of the table. The knee is flexed 45 degrees and the ankle supported.
Patient supine, The patient sits on the table with the long axis of the leg aligned to the long axis of the table, the knee is flexed 45 degrees.


Knee notch views PA and AP Patient Positions

Meschan, I. 1955 An Atlas of Normal Radiographic Anatomy Saunders, London

 
Radiation protection
Direct lead rubber gonad protection using a "half apron".

 
Central Ray
Patient Prone, the central ray is angled 45 degrees caudally and centered midway between the skin surfaces at the skin crease of the knee,
The angle between the central ray and the long axis of the tibia determines the part of the intercondylar notch shown best, at 90 degrees the anterior portion is best shown and at 100 degrees the posterior portion.

 
Exposure Factors
Kv mAS FFD (cm) Grid Focus AEC Cassette
65 5 100 No Fine No 18 x 24 cm

 

Evaluation of the Image
 ID and markers must be present and correct in the appropriate area of the film
Evidence of collimation on four sides equally around the centering point.
Limits of the examination, superiorly the femoral condyles, inferiorly the tibial plateau laterally the skin margins.
Optimal exposure should penetrate all the bone structures and contrast should be low enough to visualise fully the bone and soft tissue structures.



Rt knee Intercondylar Notch Radiograph

 
Related Projections
Knee AP and Lateral

Hughston view:  pt is prone with knee flexed 55o, the x-ray beam is directed cephalad at 45o from vertical.
Merchant view:  The pt is supine with knee flexed 45o and the x-ray beam is directed caudally, 30o from vertical.
Laurin view:  The pt is sitting with the knee in 20o of flexion and the x-ray beam is directed cephalad at 160o from vertical.

 
Additional modalities
CT
MRI