Simulation of local anaesthetic nerve block of the infraorbital nerve within the pterygopalatine fossa: anatomical landmarks defined by computed tomography.

To provide anaesthesia of the maxillary cheek teeth, a local block of the infraorbital nerve in the pterygopalatine fossa has been suggested. The aim of this study was to re-examine the anatomy of the pterygopalatine fossa, giving special attention to relevant arteries, veins and nerves; simulate the infiltration of an anaesthetic by injecting a contrast medium; improve the injection technique to avoid puncturing of relevant anatomical structures. Five heads and two living horses were investigated using contrast medium injections and computed tomography (CT). Needles were inserted using two insertion techniques: "Palatine Bone Insertion" (PBI) and "Extraperiorbital Fat Body Insertion" (EFBI). Both techniques are suitable for achieving a consistent distribution of contrast medium around the infraorbital nerve. The periorbita prevents the contrast medium from penetrating into the intraperiorbital compartment. The EFBI-technique is most appropriate for providing a sufficient infraorbital nerve block with a minimised risk of complications.