Demonstration of terminalis, olfactory, trigeminal and perivascular nerves in the rat nasal septum

Abstract The innervation of the nasal septum and around the olfactory bulb has been investigated in rats by means of whole‐mount preparations and histological sections. Silver staining, OsO 4 staining, PAS staining, cholinesterase reaction and fluorescence for catecholamine‐containing nerves were used. The nervus terminalis forms on the medial side of the olfactory bulb a ganglionated plexus, from which branches are given off which course peripherally with the vomeronasal nerves. From a dorsal part of the terminalis nerve plexus an anterior branch is given off which runs along the anterior ethmoidal nerve to the nasal vestibule where it connects with a group of ganglia. The peripheral branches of the nerve run from here along two epithelial cristae formed histologically like dermal papillae. Ventrally in the respiratory region at the junction of the nasal cavity and the nasopharynx is a 1 × 2 mm area with olfactory epithelium, glands of Bowman and an independent innervation from the olfactory bulb. This is the so‐called septal olfactory organ. Trigeminal nerves form a plexus in the respiratory region and in the vestibule, but do not supply the olfactory region. Catecholamine‐containing and cholinesterase‐positive nerves run along the meningeal arteries on the cribriform plate and accompany their branches to the vascular plexus in the olfactory and respiratory regions. Double innervation is found not only of this vascular plexus but of the venous sinuses in the swell bodies of the vestibule. The glands of the nose are not surrounded by catecholamine‐containing nerves.