A hernia or herniation is a pathological condition in which an organ or tissue of the body prolapses from its normal anatomical position into the adjacent tissue space or body cavity. This disease is mostly seen in the field of surgery, such as foramen magnum hernia in cranial surgery and inguinal hernia in pediatric surgery. Such lesions are rare in oral and maxillofacial surgery and are mostly caused by traumatic factors, such as herniation of the maxillary sinus of the orbital contents in simple orbital floor fractures or burst fractures and herniation of the buccal fat body into the oral cavity in buccal trauma. The congenital subglottic hernia with cyst belongs to the category of rare diseases, and in order to improve the understanding of primary clinicians, this paper would like to discuss the clinicopathology as follows. 1, pathological anatomy: normal sublingual glands are located in the sublingual space and are paired in both sides of the maxillary lingual sulcus. In the case of subglottic hernia or cyst, some of the glandular tissue and cyst herniate into the subglottic space, while the normal subglottic space contains only subglottic lymph nodes and some fatty connective tissue. 2. Pathophysiology: The pathophysiological basis of subglottic hernia is a congenital abnormality in the development of the unclosed median suture of the mandibular hyoid muscle. When the swallowing action is produced, there is both contraction of the supraglottis muscle group, especially the mandibular hyoid muscle, and functional contact between the dorsum of the tongue and the soft palate, both of which synergistically increase the pressure in the oral cavity, especially in the sublingual space. This elevated functional pressure presses the sublingual gland from between the chin-lingual muscle and the unclosed mid-suture of the mandibular hyoid muscle and causes it to herniate temporarily into the sublingual space, where it returns to the sublingual space as the swallowing process comes to a halt. The repeated herniation and return of the gland with swallowing may cause injury, thus increasing the possibility of subglottic hernia with cysts.3. Clinical manifestations: Subglottic hernia with cysts is mostly seen in infants and young children, because the gland is loose and incomplete at this time, and is more likely to be damaged by the aforementioned pathophysiological mechanisms. The patient has no subjective discomfort, but mainly a circular mass with a diameter of about 1M in the subchin area appears during swallowing, which is soft and painless when touched and has clear borders. With the process of growth and development, the subchin swelling can gradually increase in size during swallowing, and the body of typical sublingual gland cyst can appear in the sublingual area, but the swelling can disappear when swallowing rest is the clinical characteristic of this disease.4. Differential diagnosis and analysis of the reasons for easy misdiagnosis: the special part of the subchin area in front of the neck of this disease, the cyst-like texture is easy to be misdiagnosed as subchin dermatomal cyst at the floor of the mouth, high thyroglossal cyst, subchin lymphatic cyst adenoma, large cystic lymphatic duct malformation, as well as the cystic lymphoma. FNAC (fine-needle aspiration cytology) reveals mucinous contents and mucinous vesicles, and the correlation between the appearance and disappearance of subchin masses and the swallowing process can be used as a key basis for preoperative diagnosis of the disease, while the final diagnosis is based on the gold standard of normal tissue image and mucinous cystic cavity of the sublingual gland seen in paraffin section. and cystectomy. In one case treated by the author, part of the glandular tissue and the cyst wall were seen to enter the subglottis area during surgery, and careful exploration also revealed pathological tissue in the unclosed mandibular hyoid muscle between the sutures that appeared to be “stuck in”. In addition to complete removal of the subglottis gland during surgery, attention should be paid to the repair of the median suture of the mandibular hyoid muscle to prevent similar lesions from occurring in the contralateral subglottis gland or the ipsilateral submandibular gland.