The reason why the neck is thin is because some people are constitutionally thin and the neck also looks thin, if not accompanied by other symptoms, usually no treatment is needed, it is a normal situation. The actual neck may be thin when there is a thyroid disease, neuromuscular lesions and other problems. 1, physical wasting: physical wasting is seen in a variety of reasons, such as poor intrauterine development, personal physical differences, or eating too little malnutrition, resulting in physical wasting, slender body visually will appear thin neck; 2, thyroid disease: the thyroid gland itself can not be seen or felt, if the thyroid gland If the thyroid gland is underdeveloped or ectopic thyroid gland, it will appear to have a thin neck and differ from the normal people. The ectopic thyroid gland requires a thyroid uptake 131 iodine test to determine its incidence, which is low; 3. Neuromuscular lesions: poorly developed neck muscles can easily lead to a thin neck. Generally, a thin neck is due to the fact that it is thin in itself, resulting in a thin visual appearance. If it is not accompanied by neck pain and stiffness, no treatment is needed; if there is any related discomfort, active medical attention is required.