Although stiffness and limited motion in the shoulder joint have been described by clinicians for over a century, the etiology has remained unclear until now. There are many clinical conditions that can cause stiffness and limited motion in the shoulder joint, and therefore the diagnostic terms are confusing in clinical practice. Currently, in the middle-aged and elderly population, any pain and limitation of motion in the shoulder joint is generally classified as “frozen shoulder”. So, what does “frozen shoulder” mean in Western medicine? As early as the 19th century, several scholars diagnosed a group of conditions that caused stiffness in the shoulder joint as frozen shoulder. In 1934, American scholars proposed the concept of “frozen shoulder”, and since then the use of the term “frozen shoulder” has gradually decreased in Western medical literature. At present, although it has been suggested that the term “frozen shoulder” should be replaced by the term “adhesive capsulitis”, most scholars believe that the term “frozen shoulder” should be replaced by the term “adhesive capsulitis”. However, most scholars believe that the terms “frozen shoulder” and “adhesive capsulitis” represent two completely different groups of diseases, and therefore believe that both terms should be retained. Currently, the term “frozen shoulder” has been replaced by “frozen shoulder” and “adhesive capsulitis”. The definition of frozen shoulder is a certain degree of unexplained loss of active and passive motion of the shoulder joint without any apparent intrinsic shoulder joint disease. Currently, the term “frozen shoulder” is widely used in China. Many conditions that should not fall under this category, such as rotator cuff injury, shoulder instability, calcification of the supraspinatus tendon, and stiffness and limited motion of the shoulder joint following trauma or surgery, are misdiagnosed as “frozen shoulder”, thus delaying the best time to treat the condition. Therefore, if you have shoulder stiffness and limited movement, you should go to a regular hospital orthopedic department for an examination. The examination includes physical examination, imaging tests such as radiographs and MRI to determine the cause of shoulder stiffness and limitation of motion.