STUDIES ON THE PERIPHERAL NERVE ROUTE REACHING THE LIP OF THE GUINEA PIG, AND, DISTRIBUTION OF, NERVES, ESPECIALLY OF THE AUTONOMIC NERVES. IN THE. LIP

Abstract

Peripheral nerve routes reaching to the lip and palate were studied in the guinea pig sacrificed by suboccipital puncture, and distribution of the nerve fibers, especially that of autonomic nerve fibers was studied systematically. The following is the findings obtained in these studies:1) The trigeminal nerve which supplies the fibers to the lip and palate divide into three main brances, i. e., Nn. ophthalmicus, maxillaris and mandibulais, after emerging from the side of the pons and passing through the semilunar ganglion. The lip and palate are innervated by fine branches of the anterior superior alveolar nerve which branches off from the maxillary nerve, passes through Foramen lacerum anterior, reaches Fossa pterygopalatina and passes through the suborbital nerve canal with zygomatico-temporal branch and zygomatico-facial brach.2) The sympathetic nerve fibers are contained in the maxillary nerve, and are communicating, in their course, with perivascular plexuses and are distributed abundantly in various areas along with small vessels. Parasympathetic nerve fibers are difficult to distinguish histologically from the sympathetic nerve fibers and it is difficult to pursue, their course in detail.3) The lip is covered with cornifid squamous epithelium, with well-developed dermal papillae, and its cutis consists of loose connective tissue with a good supply of capillaries. Many striated muscle fiders running in an irregular fashion are seen in the subcutaneous adipose tissue. Skin appendages can also be seen, demonstrating the dermal nature of the lip.4) With the aid of silvar stains, it is demonstrable that the nerve bundles which are the mixture of various nerve fibers, divide into smaller bundles after reaching the periosteum, traverse the muscle layer and reach the subcutaneous tissue where they from loose nerve plexuses. The fibers branching off from these plexuses form compact plexuses within the cutis. Smaller nerve. pixeuss can also be seen within the papillae and adjacent to the basal membrane.Autonomic nerve fibers ere present mainly around the vessels in abundance, forming there fine vegetative terminal reticulum. Sensory nerve fibers form undividing or simply dividing terminal endings within the papillae. Intradermal fibers ars also demonstrable relatively in abnddance.The palate belongs histologically to the mucous membrane with few papillae formation and poorer supply of nerve fibers compared to the human palate.On the basis of these findings, histological studies of these regions of the guinea pig were made from the view-point of the comparative anatomy. Clinical significance of the anatomy of the neck, which was pointed out by H. Stolze, was discussed.A numbers of studies on Reilly's phenomen have been under-taken in our department by Suzuki, Iida, Fukazawa, Takasaki and Suzuki. Inoue, also from our department, has performed a series of experimental studies in which he demonstrated Iesions in the cervical and abdominal ganglia in the animal receiving irritating stimuli to its pharyngeal mucous membrane.The purpose of my studies has been to give support from anatoinieal-histolagical view-point to the results of these studies as well as to the concept that the autonomic nerve plays an impor-tant role in above mentioned studies.