Pterygoid shoulder refers to a symptom, not an injury. In a normal person, the scapula abuts the chest wall, which is accomplished primarily by the synergistic contraction of the serratus anterior and trapezius muscles. If the anterior serratus and trapezius muscles are paralyzed and weak, the scapula can lose its force against the chest. When the upper arm movement rotates the scapula, its inner edge will appear to be deformed backwards, forming a pterygoid scapula. Pterygoid shoulder can affect the patient’s ability to lift, pull, and push heavy objects, and in some severe cases, some daily activities such as dressing and combing hair can be affected. Pterygoid shoulder is a dysfunction of the shoulder muscles, usually due to paralysis and injury of the long thoracic nerve and the paramedian nerve that innervate the anterior serratus and rhomboid muscles, causing dysfunction and paralysis or atrophy of the muscles they innervate, generally speaking, paralysis of the anterior serratus is more common, while the rhomboid and rhomboid muscles are less common. The etiology is divided into traumatic, non-traumatic and idiopathic. Traumatic includes blunt pulling (carrying, carrying, lifting, washing the car for a longer period of time, sleeping with pressure on the upper extremity, reading a book with a hand pillow, etc.); pulling or blunt filing injury by acute direct violence; repeated pulling (athletes lifting weights, throwing), etc. Inflammation and mass compression can also cause nerve palsy. Non-traumatic include viral infections (influenza, tonsillitis, polio), allergic reactions to drugs, poisoning (de-rusting agents, tetanus), and cervical 7 nerve root lesions. There is also a proportion of patients with unknown etiology, called idiopathic. Clinical manifestations depend on the severity of the affected muscles or nerves: 1. mild to severe pain in the shoulder and back; 2. shoulder weakness, fatigue and inability to use the upper arm; 3. scapula flanking and discomfort when raising the arm; 4. severe inability to raise the arm above shoulder level, unable to complete actions such as dressing and combing the hair; 5. anterior serratus paralysis, when the arm is raised in front of the body, the scapula moves backward When the trapezius muscle is paralyzed, the scapula moves to the opposite side when the arm is raised on the side of the body to form a wing shape; 7. When the scapula is pressed by hand, the patient feels comfortable when raising the arm; 8. Treatment: 1. Non-surgical treatment Most patients with pterygoid scapula caused by blunt trauma or unknown causes can usually recover within 1 year. If the anterior serratus or trapezius function is not restored after 1 year, surgical treatment is required. Conservative treatment includes: (1) avoiding any activity that may re-injure or strain the recovering nerve; (2) exercising the muscles around the scapular band. 2.Surgical treatment After 1 year of conservative treatment, patients who have not recovered and still have pain can be treated surgically. Tendon transfer is the main procedure, and severe cases may require scapular chest wall fusion.