The true neurogenic thoracic outlet syndrome (TOS), one type of the TOS, has vague and controversial clinical symptoms, so a variety of diseases can mimic the presentation of TOS, especially ulnar neuropathy or cervical root lesion. For most patients with TOS, common practice is to offer a course of conservative treatment, but its kinds are not enough and pain is too severe to do that in the chronic state. We experienced a case of true neurogenic thoracic outlet syndrome with distinctive clinical symptom and abnormal electrodiagnostic findings. The symptom was not controlled by conservative management including oral medication or physical therapy. So we injected type A botulinum toxin (BotoxⰒ) in the scalene and pectoralis minor muscles with ultrasonography guide. After 2 weeks, the pain decreased in visual analogue scale nine to four, and the compliance to physical therapy was improved. The result appeared to demonstrate that botulinum toxin injection may be helpful in controlling symptoms and making the patient adapt in physical therapy in the difficult case to management by any other methods. (J Korean Acad Rehab Med 2008; 32: 119-122)
