As the dental pulp is a highly vascularised and innervated region of the tooth, it is the site of origin for most pain-related sensations. The dental pulp nerve is innervated by one of the Trigeminal nerves, otherwise known as the fifth cranial nerve. The neurons enter the pulp cavity through the apical foramen, and branch off to form the nerve plexus of Raschkow (as mentioned earlier). Nerves from the plexus of Rasckow give branches to form a marginal plexus around the odontoblasts, with some nerves penetrating the dentinal tubules.