Diffusion sounds like a detail for clinical journals, and at the level of exactly how a molecule spreads through tissue, it is. But "field of effect" — how far a neurotoxin spreads from where the needle goes in — is one of those clinical properties that quietly shapes things an owner cares about: how protocols should be standardized, why complication patterns emerge, and why two products dosed identically can land differently. You don't need to inject to benefit from understanding it; you need enough grasp to build sensible protocols and read your outcomes accurately.
This is general education for owners, not medical advice. Injection mapping and dosing are clinical decisions for trained injectors.