Frequency and evolutionary importance of human palatal pneumatization (918.13)

Abstract

Pneumatization of the human hard palate is rare but, when present, occurs via maxillary sinus expansion. Emil Zuckerkandl, the father of sinus anatomy, was the first to document this condition in 1892, illustrating a clear communication between maxillary sinus and hard palate. Later studies have given frequencies of less than 5% with a slightly greater commonality among females. Still others have described palatal pneumatization among a range of non‐human animals including our closest living relative, the chimpanzee. This study examined CT scans from 200 human heads to quantify the frequency of palatal pneumatization and assess for relationships with variables of age, sex, and ancestry. Results showed that only two individuals exhibited palatal pneumatization. One was a European female and the other an Indian male, both aged 20‐40 years. Thus palatal pneumatization occurred at a rate of 1% in our sample with no observable relationship with sex or ancestry. Conversely, most chimpanzee crania exhibited extensive palatal pneumatization, a potential consequence of greater robusticity of the masticatory apparatus. Other non‐primate animals such as deer and mountain goats also exhibited extensive palatal pneumatization, which are apparently homoplastic. Nonetheless, the expression of a pneumatized hard palate among chimpanzees and humans may be a shared derived character inherited from a common ancestor approximately 6.5 million years ago.