Analysis of the suprabullar and retrobullar recesses for endoscopic sinus surgery.

Presently, the basic structures and spaces of the paranasal sinuses are more clearly understood by otolaryngologists than ever before. Yet, the more subtle and complex ethmoid features, especially of the ethmoidal pre-recesses and recesses, still elude many otolaryngologists. One of the most nebulous, elusive, and difficult-to-understand recesses is the sinus lateralis, or as it is more correctly called, the retrobullar and suprabullar recesses. The primary purpose of this investigation was to ascertain the prevalence of the sinus lateralis in humans. The secondary purpose was to better characterize this subtle feature of ethmoid anatomy. Human cadaver sinonasal complexes were meticulously dissected by both gross and endoscopic techniques. The hiatus semilunaris superior and sinus lateralis were present in all specimens. A separate and discrete retrobullar recess was present in 93.8%. Typically, a crestlike projection from the basal lamella to the lamina papyracea was noted within the posterior aspect of the retrobullar recess. A single, discrete, well-developed suprabullar recess was present in 70.9%, and a rudimentary suprabullar recess was present in 22.9%. In 7.2%, a single large cleft collectively excavated the retrobullar and suprabullar recess areas; separate retrobullar and suprabullar tracts were not present in this subgroup. Typically, the suprabullar recess was separate from and did not communicate with the frontal recess. The data from this investigation indicate that the separate terms retrobullar recess and suprabullar recess more accurately designate the anatomy and are recommended over the term sinus lateralis.