The term 'concha bullosa' refers to the pneumatisation of the intranasal turbinates. The pneumatisation can occur at any level (superior, middle, inferior), but the term is typically used to describe the aeration of the middle turbinate. This case report concerns a medieval skull from Tomb Chamber Number One in St. Nicholas's Church in Glogow, Poland. The burial dates from the 13th or 14th century. Direct measurements of the skull according to Martin's technique and computed tomography (CT) were made. The skull is from a male whose age was estimated as 40-55 years. In the nasal cavity, a large bony formation with the appearances of a tumor, a lesion of the maxillary sinus wall, and a significant curvature of the nasal septum were found. The CT scan demonstrated changes that could be described as a type IV concha bullosa, according to Krzeski's classification. This anatomical variation was first described by Zuckerkandl in 1893. The symptoms that were often associated with concha bullosa include nasal obstruction or congestion, facial pain, and headache. Concha bullosa can result in recurrent sinusitis, mucocele, or mucopyocele. In the case of the Glogow skull, an extensive lesion and inflammatory changes in the maxillary sinus and destruction of the orbital floor suggests the presence of a mucopyocele that arose from a concha bullosa. Copyright (C) 2009 John Wiley & Sons, Ltd.