Comparative applied craniofacial morphometry in popular brachycephalic breeds: A tool for preventive medicine and risk stratification

Brachycephalic dog breeds are globally popular, yet their craniofacial morphometry is rarely quantified in clinical settings. Since each breed possesses distinct traits, individual assessment is crucial. This study aimed to assess and compare cranial features of healthy French Bulldogs (FB), Pugs (P), and Shih Tzus (S), utilizing 25 dogs per breed (n = 75). Morphometric measurements included body weight, muzzle length (ML), skull length (SL), skull width (SW), palpebral fissure length (PFL), relative palpebral fissure length (RPFL), cephalic index (CI), and craniofacial ratio (CFR). Also, Body Weight was computed. All dogs were classified as extreme brachycephalic (CFR < 0.2; CI > 0.81). Significant breed-specific correlations were observed, notably between CFR and SW in FB, CFR and PFL in Pugs, and SL and SW in Shih Tzus. The French Bulldog was the heaviest breed, characterized by the widest skulls and largest palpebral width. Pugs exhibited the lowest CFR and shortest muzzles. These findings emphasize that the brachycephalic phenotype manifests heterogeneously across breeds. Consequently, from a preventive medicine perspective, these breeds cannot be treated as equivalents; clinical assessment and monitoring must be tailored to their specific anatomical profiles. This study provides reference data for clinical use and supports future research into breed-specific craniofacial anatomy.