What are the film techniques for broken and protruding bones?

Question

I have seen in a James Bond movie where there is a volcano disaster and the guy being James Bond (or the same person maybe just different movie) that when he and his host family during the eruption found salvation in a collapsed cave, James Bond went back to the crashed car to get the signal location beacon while the others were deep in the cave.

When there is a small rock fall and he is directly under it, his leg breaks thoroughly and cleanly, it literally looks like he actually did snap it (and his leg was on an awkward angle too).

How do they film this and what do they actually do with the 'broken bones'?

Answer 1

Using practical make-up effects / amputees

This is an interesting blog post about how to Make a Realistic Makeup Compound Fracture.

Essentially it's using different materials to build up a realistic looking wound:

Answer 2

I agree with Longshanks' answer regarding makeup to create a realistic-looking wound.

To film the actual action of a bone breaking, these will frequently be "insert shots". That is:

1. The character is shown walking or moving, in a long camera angle that shows their whole body.
2. The camera angle cuts to what appears to be a close-up shot of the limb that is about to break. It's actually not the same limb, but a fake limb - like a fake "leg" inside a pair of pants that match the actor's.
3. The fake limb is then broken. This is accompanied by a sound effect that sounds like a bone breaking.
4. Often a "reaction shot" is put here: A close-up of the actor's face, as he/she looks down at his/her injury and screams or winces in pain.
5. The camera angle cuts back to the long camera angle where the character was walking or moving. However, the actor now has makeup that looks like a broken bone, or has some prosthetic in his/her costume that make the limb look as though it is bent at an odd angle.

When run together in the span of 1-2 seconds, this seems to the audience like a continuous set of events, though they were all probably shot over the course of hours rather than seconds.