This article presents a unique diagnostic test for the neurogenic thoracic outlet syndrome (nTOS). nTOS is one of the most misdiagnosed and controversial medical problems; the diagnosis is clinical, and there are few specific diagnostic criteria for this condition. We would like to share this unique diagnostic modality, the Tafler test, with medical professionals. The Tafler test helps diagnose nTOS, differentiate it from cervical radiculopathy and carpal tunnel syndrome, and effectively tailor treatment for its symptoms. The following case series aims to describe several patients with nTOS who had failed previous treatment with surgery, physical therapy, and analgesics. The implementation of the Tafler test as a treatment modality in combination with osteopathic manipulative treatment (OMT) and physical therapeutic modalities led to significant improvements in treatment efficiency.