The route of the lymphatic vessels from the periodontal ligament to the mandibular foramen of the rat

Abstract

The route of lymphatic vessels from the periodontal ligament to the mandibular foramen was studied in five male SD rats. After the animals were killed with an overdose of anesthesia, the mandibles were fixed, decalcified and embedded in GMA resin. Serial sagittal sections were made, stained and observed in a photomicroscope. In addition, the route of the lymphatic vessels from the periodontal ligament to the mandibular canal was three-dimensionally reconstructed. The lymphatic vessels in the periodontal ligament ran together with veins passing along the wall of the alveolus. In the apex region and the alveolar canal, they were located close to veins running together with arteries and nerves. In the alveolar part of mandibular canal, the vessels ran together with veins passing along the upper wall of mandibular canal. In the mandibular canal within the ramus of mandible, they separated from the upper wall of the mandibular canal as veins increased in diameter. The part of the mandibular foramen of the mandibular canal, the lymphatic vessels ran between veins and arteries. We conclude that the pressure producing the lymphatic flow is generated by masticatory force and arterial pressure in the periodontal ligament, by arterial pressure in the alveolar part of the mandibular canal, and by arterial pressure and the muscular pump of the medial pterygoid muscle in the mandibular foramen of the mandibular canal. The mandibular canal within the ramus of mandible is supposed to be the transitional region between the inside and the outside of the mandibule.