Ankle Flashcards
How do you identify a properly positioned AP ankle?
•medial mortise is open
•tibia superimposed one half of distal fibula
•tibiotalar joint space is open
How much of the tibia and fibula need to be included in an ankle projection?
1/4
Why is the lateral joint space closed on an AP ankle?
Fibula sits more posterior
How do you identify external rotation on a AP ankle?
•medial mortise is closed
•tibia superimposes more than 1/2 of the fibula
How do you assess internal rotation on a AP ankle?
•medial mortise is closed
•tibia superimposed less than 1/2 of fibula
What degree of angulation is used for a AP oblique mortise?
15-20 degrees
How do you identify a correctly positioned AP oblique mortise ankle?
•distal fib is demonstrated without talar superimposition ( open lateral mortise)
•tibia superimposes 1/4 of distal fib
*entire mortise is open
What is the positional error of an AP oblique mortise if the tibia superimposed more than 1/4 of the fib and medial and lateral mortise are closed?
Insufficient internal rotation
What is the positional error on an AP oblique mortise if the tibia superimposed less than 1/4 of the fib and the lateral mortise is open?
Excessive internal rotation
(A bit less than 45 degrees)
What is the degree of obliquity for an AP oblique ankle?
45 degrees
How do you identify a properly positioned AP oblique ankle (45)
•distal tibfib joint is open
•medial mortise closed
•lateral mortise partially open
•fibula seen without tibial superimposition
What is the positional error of an AP ankle (45) if the sinus tarsi is poorly demonstrated?
Insufficient internal rotation
What is the positional error of an AP oblique ankle (45) if the sinus tarsi is seen clearly?
Excessive internal rotation
What is the positional error of a AP oblique ankle if the calcaneus superimposed the distal aspects of the lateral mortise and distal fibula?
Insufficient dorsiflexion
Why is the base of the fifth MT included in a lateral ankle/foot?
Allows to be evaluated for a Jones fracture (inversion injury)
