An Angular, Component-Based Approach to Soft-Tissue Cephalometric Analysis: Localizing Profile Imbalance to the Nose, Lips or Chin from a Single Vertex (N) and Reference Axis (N–C)

This preprint proposes an angular, component-based method for soft-tissue cephalometric analysis of the facial profile. Every measurement uses one vertex, soft-tissue nasion (N), and one reference axis, N–C (nasion to soft-tissue pogonion). Profile features are expressed as angles opened from N: the nose (C-N-K), the upper lip (U-N-C) and the lower lip (L-N-C). This makes it possible to tell whether a profile imbalance comes from the nose, the lips or the chin. The method separates modifiable (free) components that treatment can change from non-modifiable (embedded) components. It then follows a fixed diagnostic key that always starts with the nose–chin frame (C-N-K). A worked demonstration shows that Ricketts' E-line can misdiagnose normal lips when only nose size changes. The angular analysis keeps the lips normal and locates the problem in the nose: a large nose needs nose reduction and a small nose needs nose augmentation. The paper covers landmark definitions, the angular parameters, the diagnostic workflow, four worked clinical examples, limitations and a validation roadmap. The goal is one shared, reproducible soft-tissue map that orthodontists, maxillofacial surgeons and rhinoplasty surgeons can all use.