Cracks in the middle of the tongue are mostly caused by fissured tongue, and the possible causes include systemic diseases, genetic factors, and infections. Cracks in the middle of the tongue are mostly seen in patients with fissured tongue, which is also known as fissured groove tongue and grooved tongue, refers to the surface of the tongue body with longitudinal and transverse fissures and cracks. The pathogenic mechanism has not been clearly defined, and may be related to systemic diseases, heredity, infection and other factors: 1. Systemic diseases: Down syndrome, malnutrition, vitamin B2 deficiency, syphilis infection, psoriasis, pemphigus, Melkersson-Rosenthal syndrome, dry syndrome, etc. are often accompanied by furrowed tongue. 2. Genetic factors: there is a high incidence of cracked tongue family line, with genetic predisposition. 3. Infectious factors: such as syphilitic tongue infection caused by syphilitic spirochetes, longitudinal cracks on the tongue surface can occur. In addition, delayed hypersensitivity reaction, mossy lesions, etc. may also be associated with the development of cracked tongue. The appearance of related symptoms should be timely medical care, under the guidance of the doctor to clarify the diagnosis and treatment.