Surgical anatomy of the sphenopalatine foramen and its arterial content

The sphenopalatine artery is the end artery of the maxillary artery located within the pterygopalatine fossa and passes through the sphenopalatine foramen (SPF) on lateral nasal wall. Nasal bleeding from this artery is potentially life threatening and may urgently require endonasal endoscopic occlusion. The aims of the present study have been first to investigate the location of the SPF, secondly the pattern of the main branches of the sphenopalatine artery at the foramen. 12 adult dry skulls and 6 adult cadaver heads injected within Indian Ink have been analyzed under an operating microscope Leica. All measurements were assessed using a digital calliper. The inferior border of the SPF has been situated 18.27 mm (15.09-20.87 mm) above the horizontal plate of the palatine bone and 13.04 mm (9.01-14.85 mm) above the horizontal lamina of the nasal inferior turbinate. Endoscopically, the posterior wall of the maxillary sinus is located at the level or anteriorly within 10 mm to the anterior border of the SPF. In all cases, the anterior border of the SPF is characterized by an easy recognizable sharp bony crest at the narrow middle part of the hourglass shape foramen. The SPF is 6.13 mm high (5.24-6.84 mm), with deep grooves extended superiorly and inferiorly from the foramen in eight skulls (8/12). The posterior lateral nasal artery which courses inferiorly and vertically (diameter 1.80+/-0.20 mm) and the nasal septal artery which courses superiorly and vertically (diameter 1.30+/-0.30 mm) have been the two major branches just leaving the SPF. One or two smaller collateral branches (diameter less than 1 mm) to the superior and/or the middle turbinate can get out coming from the stem of the main branches or directly from the SPF. So, the success rate of sphenopalatine artery ligation during endoscopic surgical procedure needs selective dissection of the two main branches of the sphenopalatine artery close to the SPF.