1

Note the relative positions of the bones of the foot:
Neutral position of the subtalar joint occurs when it is neither supinated nor pronated. When the foot is pronated, the head of the talus tends to adduct, and protrude medially behind the navicular. When the foot is supinated, the head of the talus tends to protrude laterally. When the head of the talus is not palpable on the lateral or medial side, the subtalar joint is considered to be neutral.

2

The navicular, the head of the talus and the medial malleolus are in aline which goes dorsally and posteriorly.

3

To locate the head of the talus on the medial side, pronate the foot, locate thenavicular with your thumb, then move your thumb in a dorsal and posterior direction towards the medial malleolus. You will feel the protruding head of the talus.

4

To locate the head of the talus on the lateral side of the foot,supinate the foot and the head of the talus will protrude.

5

Pronate the foot and palpate the head of the talus medially with thumb. Supinate the foot and palpate laterally with index finger. Rotate until you no longer feel the head of the talus. The subtalar joint is now in neutral position.

6

The neutral position cast should be taken:

1. with subtalar joint held in neutral position;
2. with fourth and fifth metatarsal heads loaded (apply pressure) to pronate midtarsal joint; and
3. with ankle joint dorsiflexed to resistence.

7

The impression casting should be done with the patient relaxed andsitting with legssupported.

8

You will require four 5" x 30" plaster of paris splints, folded in half, and a bowl of warm water. A few teaspoons of alum will greatly reduce setting time.

1. Immerse dry splints in water.
2. Drop and fold into your hand and squeeze out excess water.
3. Pull plaster straight out, removing wrinkles.

9

Place the splint so it extends from behind the first metatarsal head,around the heel to the fifth metatarsal head.

10

Fold one side of the plaster just over the centre of the foot. Fold over the other side and close up seam. The tab at the bottom should be pushed back off the plantar surface and onto back of heel.

11

Take the second splint, moisten, and drape over the top of the toes.Place your finger under it, fold one side over, then the other.

12

Take the tab at the top and push it off the plantar surface and into the toes. With the palm of your hand, rub the plaster into the contours. The surface should be very smooth.

13

Place the thumb over the fourth and fifth metatarsal heads. Now hold the foot in neutral position. Check that the patient is relaxed and that the foot is loose. Hold in this position until the plaster dries sufficiently that you can audibly tap on it.

14

REMOVING THE CAST
Pull the skin away from the top edge of the cast. Grasp on the sides of the heel and pull straight down.

15

As soon as you have pulled the cast below the level of the heel, pull it forward and slide it along the plantar surface of the foot.

16

Check that the inside of the finished impression is very smooth and clean.