The asymetrical Frontal Sinuses are paired paranasal sinuses between the outer and inner tables of the frontal bone. Each sinus drains through the frontonasal duct into the infundibulum which is continuous with the hiatus semilunaris. The frontal sinuses are innervated by supraorbital nerves.
Traumatic penetration through the posterior wall of the frontal sinus with transmission of bacteria may result in an epidural abscess.
Pain from frontal sinusitis is a common cause of headaches.