Cervical segmentation insufficiency This condition, also known as Klippel-Feil syndrome, short neck deformity, and cervical fusion, is a congenital deformity characterized by fusion of the cervical spine. It generally consists of two or more cervical vertebrae fused with each other and can be combined with a variety of deformities. Etiology and pathogenesis】 The disease is mostly epidemic, the cause is unknown, and some of them may be autosomal dominant or recessive. It may be related to the defect of mesodermal segmentation at 3-7 weeks of early embryonic life, or the intervertebral disc does not occur or ossify due to the developmental disorder of the intervertebral tissue that should occur as an intervertebral disc. [Pathology] Cervical fusion is mostly of two vertebrae and rarely of more than two. The fusion may be partial or complete, resulting in fusion of the vertebral plate, arch and spinous process, with cervical 2 and 3 fusion being the most common. The fused vertebrae may be underdeveloped, unevenly sized, and flat and wide, and there may be osteophytes, vertebral stenosis, and disc herniation. Diagnostic points】 1.Diagnostic points Overview The diagnosis can be confirmed according to clinical manifestations and imaging examinations, and further examinations should be conducted to exclude other combined deformities. 2, imaging examination X-ray film can be seen in several cervical vertebrae and spine fusion at the same time, or spine fusion alone, vertebral body development is incomplete, spine development deformity and formation of pseudo-joint, cervical physiological curvature disappeared. Cervical fusion is mostly seen in cervical 2 and 3. MRI can further show spinal stenosis, disc herniation, nerve root compression and other deformities. Treatment overview】 No treatment is needed for asymptomatic patients, but observation and follow-up should be carried out. Those with nerve root symptoms can be treated symptomatically, such as physical therapy, and surgery should be considered for those with significant spinal cord compression or cervical instability in head and neck hyperextension and hyperflexion.