The "crumple zone" hypothesis suggests that the paranasal sinuses protect the brain as a zone to distribute and absorb energy after trauma to the head. We investigated the relation between the size of the frontal sinus and mortality in patients with cranial trauma. All patients with head trauma admitted to the ICU between 1 January 2016 and 20 December 2017 were reviewed retrospectively. They were divided into two groups (according to their outcome) : died and survived. The volumes of the frontal sinuses and other trauma-related variables were assessed on computed tomographs (CT) on admission. Admission CT of 33 patients (24 male, and nine female, aged between 18-92 years, mean 43) were obtained. Male patients had significantly larger frontal sinuses than female (10.24 compared with 6.6 cm3). Larger sinuses were significantly associated with a worse outcome (p = 0.005). The size of the frontal sinus correlates with mortality after cranial trauma. Our findings do not confirm the "crumple zone" hypothesis, and suggest that the larger the sinus, the greater the risk of death. To our knowledge this is a new finding that warrants further validation. (C) 2019 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.