Sanders classification is predominantly based on which part of the calcaneus?

• A. Sustentaculum tali
• B. Posterior facet
• C. Calcaneal tuberosity
• D. Anterior facet

Answer: (B)

The part of the calcaneus most central to this classification is the posterior facet, the articular surface that forms the subtalar joint. This surface bears the load during heel impact, and the extent and pattern of fracture lines within it determine how much the subtalar joint is crushed or displaced. Sanders uses CT imaging to assess how many articular fragments involve the posterior facet and to what degree the facet is comminuted. This focus on the posterior facet—rather than other calcaneal regions like the sustentaculum tali, the calcaneal tuberosity, or the anterior facet—drives the categorization, because the amount of articular disruption here best predicts joint congruity and future arthritis, guiding treatment decisions.