Anatomic variants in the frontal sinus have significant implications in endoscopic sinus surgery. In this illustrative study, the authors describe a newly-observed anatomical variant – a mucosa lined prism‑shaped space between the most superior part of the nasal septum and the central floor of the frontal sinuses. CT scans of 400 patients were reviewed to illustrate this anatomical variant which varied in its anterior, inferior and posterior extensions. Named as fronto-septal rostrum, its present was noted in 30.5% of the scans examined. There was no gender difference, except that it was narrower at the glabellar region in males. The laterality was equally distributed. This was also present in four of the 19 children in the cohort. The pathological implication is that this may be mistaken for a septal abscess, simple drainage of which may not help. The surgical approach to the frontal sinus may be helped if the presence of this structure is utilised and sometimes may obviate the need for doing more complex procedures, such as Draf III for a failed Draf IIB. Surgical widening of the fronto-septal rostrum would improve the infero-anterior exposure to crista galli. The authors note a bias: that CT scans were done only in patients with sinus complaints.