Made of little things.

/** Normalized illustration amount. This is not a measured angle or TMJ model. */
export function parseJawOpening(value: unknown): number {
  if (typeof value !== 'number' || !Number.isFinite(value) || value < 0 || value > 1) throw new Error('Invalid jaw opening.');
  return value;
}
export function describeJaw(opening = 0): string {
  return opening > 0 ? `jaw ${opening >= .75 ? 'open' : 'partly open'} in illustration (not a measured range of motion)` : 'jaw closed in illustration';
}
export const mouthLimit = 'Adult reference mouth: 28 permanent teeth labeled with FDI numbers, exposed roots, a coarse tongue and jaw bones. No wisdom teeth, gums or palate are modeled. Exposed roots and gaps are atlas display choices, not findings. Tongue motion is schematic.';