0:00

So now we'll turn our attention

0:01

to the lower extremity, ankle and foot.

0:05

The ankle is the most commonly injured weight-bearing joint

0:08

with ankle fractures being very common.

0:10

They can be low energy, rotational injury mechanisms

0:13

that produce malar fractures.

0:15

You can have higher energy

0:16

and impaction injuries such as the pelon fracture

0:20

and injuries to the ankle and foot are often multiple.

0:23

So this is an area where we particularly need

0:25

to be concerned about potential satisfaction

0:27

of search issues and should use the checklist.

0:31

So the ankle joint proper is composed of two joints.

0:33

There's the true ankle joint of the tibia, fibula

0:36

and TAUs, which provides dorsiflexion and plantar flexion.

0:41

And then below that we can consider the subtalar joint

0:44

or the posterior tail calcaneal joint

0:46

where we have an articulation between the tailless

0:49

and the calcaneus, which allows for inversion

0:52

and aversion, helps smooth out walking over uneven surfaces.

0:56

So the ankle joint itself is a hinge joint formed

1:00

by the tibia fibula and Alis.

1:02

Here on the projection radiographs,

1:04

we typically do an AP oblique and lateral projection.

1:07

These are the key anatomical structures

1:09

that are identified here.

1:11

If we come down the distal tibia, we want

1:13

to notice the distal tibial articular surface.

1:15

We is known as the PlayOn.

1:18

We have the ankle mortis, which is over the Taylor dome.

1:22

There is a medial bony prominence known

1:25

as the medial malleolus

1:27

and the lateral bony prominence of the lateral malleolus.

1:30

On the oblique projection, which is called a mortis view,

1:33

it better depicts the ankle mortis

1:36

on the lateral projection.

1:38

We can now identify the subtalar joint labeled

1:41

as the tail calcaneal joint here, the calcaneus,

1:45

the transverse tarsal joint, which is also known

1:48

as the show part joint, the navicular bone

1:51

and the cuboid bone.

1:54

So on radiographs, one of the areas that's often, uh,

1:57

looked at or considered part of the checklist is the angle

2:00

of Joss saying forms a lateral border of the posterior facet

2:04

and the anterior aspect of the lateral calcaneus.

2:08

Normally that is about a hundred to 130 degrees.

2:11

And what some orthopedic surgeons look at is boar's angle,

2:16

which is measured off of the apex

2:19

of the posterior tuberosity

2:21

and posterior articular surface with the apex

2:23

of the anterior process and the posterior articular surface.

2:27

And typically it's approximately 20 to 40 degrees.

2:30

I would say that radiologists don't routinely measure

2:33

that angle, but it is an important relationship to be aware

2:36

of to eyeball, whether it's normal

2:38

or abnormal, can be a sign of a subtle calcaneal lesion.

2:42

So here the two radiographs are focused

2:44

on the show part joint.

2:46

So we have the midfoot articulations,

2:48

so we have the medially, the tailless

2:50

and navicular bone articulating

2:52

and laterally the calcaneus and the cuboid.

2:56

Now as we move from the ankle to the foot, it's

2:58

Very important that foot radiographs are performed.

3:01

Weight-bearing if the patient can tolerate it,

3:03

'cause that allows us to assess the normal alignment.

3:06

So our AP projection is typically done

3:08

with a 15 degree cephalad tilt

3:11

and weight-bearing as often as possible,

3:13

unless there's some patient reason

3:16

or other acute process going on.

3:18

We wanna consider the middle column,

3:21

which is the medial border of the second metatarsal

3:24

with the medial border of the middle qof form.

3:28

The inter metatarsal space between the first

3:30

and second metatarsals is equal to the space

3:33

between the medial and middle qof forms.

3:36

Now in the foot we also obtain a 30 degree oblique

3:40

projection, and here we wanna identify

3:42

that the lateral border of the third metatarsal is

3:45

continuous with the lateral border of the lateral canfor

3:50

and that the medial border of the fourth metatarsal

3:53

is continuous with the medial border of the cuboid.

3:57

The inter metatarsal space between the second

3:59

and third metatarsals should be equal to the space

4:02

between the middle and lateral C forms.