FOOT LATERAL Flashcards
What are the two fat pads of the foot?
Pre Talar fat pad - anterior to the ankle joint and rests next to the neck of the talus.
Posterior fat pad - indentation formed by the articulation of the posterior tibia and the Talar bones.
How does the pretalar fat pad get displaced?
The synovial lined capsule attached to the tibia, fibula and the talus, when secreting synovial fluid gets distended displacing the pretalar fat pad. This does not occur with the posterior precpasular fat pad. It requires more fluid evasion to be displaced.
Why is dorsiflexion advantageous than plantar flexion?
Plantar flexion causes the flattening of the anterior fat pad, reducing its usefulness for joint effusion. Dorsiflexion puts the tibiotalar joint in a neutral position, tightening all the ligaments and muscles, preventing the foot from resting on the forefoot. It defines the medial arch, as well as preventing foot rotation thus decreasing the superimposing of the MT heads.
How do you obtain an accurate lateral foot from a patient who is unable to dorsiflex?
Sponge under slightly flexed knee
Short critique of the lateral foot
Contrast and density is sufficient to see the two fat pads
Long axis of the foot is aligned 90 degrees to the lower leg
MT heads are superimposed
Proximal aspects of the Talar domes are aligned
Distal fib at posterior half of tib
Distal tarsals are at centre of collimation field.
With a patient that can dorsiflex, how do you get their foot lateral and what happens if they have a large upper thigh?
Keep their knee and leg extended.
Elevate the foot and IR with a large upper thigh.
How do you asses if one Talar dome is more proximal to the other?
Measure the height of the medial arch by the amount of cuboid posterior to the navicular. Normally you should see 1.25 cm of cuboid.
Second way is to see the widening of the talocalcaneal joint. Narrow joint then lateral dome proximal and open joint then medial dome is proximal.
Can change this by depressing or elevating the knee and forefoot.
On a weight bearing lateromedial foot, how does the lateral dome become proximal?
With medial rotation
What happens when you put pressure on the forefoot and on the heel?
Forefoot - medial dome anterior
Heel - medial dome posterior
How do you position for a lateral foot X-ray?
Externally rotate the hip and leg to get the foot parallel to the IR.
Centre to the 5th MT base
Include 2.5 cm above the medial malleolus.
