[The diffusion route of Indian Ink injected into the infraorbital nerve trunk at the infraorbital foramen of the rabbit].

The purpose of this experimental study was to investigate the disseminating routes of viruses, bacteria, tumor cells and various substances along the trigeminal nerve sheaths. Thirty-four rabbits weighing approximately 3 kg were used for this study. After an intraperitoneal injection of sodium pentobarbital, the left infraorbital foramen was exposed surgically. Then, various amounts of Indian ink solution were injected with a syringe driver for continuous microinfusion into the infraorbital nerve trunk at a rate of 0.03 ml per minute. In all cases, during the appropriate state of general anesthesia, intravascular perfusion was performed with 10% folmaldehyde. The cranial and facial part of the rabbit were separated, decalcificated by Plank & Rychlo's method, dehydrated in an alcohol series, and embedded in 8% celloidin. Finally, 30 or 40 micrometer thick sections were stained with Hematoxilin-Eosin. The following results were obtained: (1) The Indian ink injected into the infraorbital nerve trunk at the infraorbital foramen diffused along the infraorbital nerve and maxillary nerve, but did not reach the trigeminal ganglion. (2) The Indian ink diffused along the nasal branches of the infraorbital nerve and reached a point near the nose tip. (3) The small branches of the infraorbital nerve and its accompanying vessels penetrated the bony wall of the maxillary sinus, and the Indian ink reached the proper layer of the sinus mucous membrane.