Quantification and Anatomy of the Sinus of Morgagni at the Skull Base

The sinus of Morgagni, lying in the coronal plane between the left and right portions of the superior pharyngeal constrictor muscles at the posterior skull base, has not to our knowledge been studied in detail by anatomical observation. As this area may be implicated in tumor spread and is near many important cranial base structures, the present study was warranted. The sinus of Morgagni was dissected in twelve formalin-fixed adult cadavers (24 sides) with particular attention to anatomical relationships. The dimensions of this region were quantified. The Eustachian tube pierced the sinus of Morgagni laterally in all specimens. The distance to the foramen ovale was found to average 2.5 cm from the midline and 1.2 cm from the nearest aspect of the sinus of Morgagni. In view of the proximity of the sinus of Morgagni to the foramen ovale and of our findings, anterior transcutaneous procedures for approaching this skull base structure could potentially allow infiltrate to enter the retropharyngeal space with spread to the superior mediastinum.