The diameter of the parotid duct is between 0.5 and 1 mm when it is not working in normal flaccid condition. The parotid duct is formed by the convergence of many parotid lobules and tubules, which penetrate the anterior margin of the parotid gland and open into the oral cavity, and its total length is about 5 cm, located on the superficial surface of the biting muscle. The parotid gland has a close relationship with the external carotid artery and the internal jugular vein. The external carotid artery converges into the parotid gland and passes upward through the parotid gland to supply blood to the parotid gland. The parotid gland is a secretory gland in the body that opens into the mouth and contributes to certain digestive functions, and together with saliva can initially hydrolyze and digest starches. Diseases affecting the parotid gland include acute and chronic parotitis, various mixed tumors of the parotid gland, malignant tumors of the parotid gland, and various hemangiomas growing in the parotid gland.