Infraorbital Nerve Block within the Pterygopalatine Fossa of the Horse: Anatomical Landmarks Defined by Computed Tomography

In order to provide anaesthesia of the equine maxillary cheek teeth, a local nerve block of the infraorbital nerve in the pterygopalatine fossa had been proposed, which is referred to as the “Palatine Bone Insertion” (PBI). As several complications with this method were reported, our study was designed to recommend a modified injection technique which avoids the risk of puncturing of relevant anatomical structures. Five cadaver heads and two living horses were examined by contrast medium injections and subsequent computed tomography (CT). Spinal needles were inserted using two different insertion techniques: The above mentioned (PBI), and a modification called “Extraperiorbital Fat Body Insertion” (EFBI). Both techniques (PBI and EFBI) provide a consistent distribution of contrast medium around the infraorbital nerve. However, only the EFBI technique is appropriate to minimize the risk of complications. This study is an example for the permanent challenge of anatomists to supply a basis for clinical and surgical procedures.