The thoracic outlet syndrome (TOS) is a disputed syndrome in the field of the so-called compression syndromes of the upper extremity. This is no surprise, as the TOS is a complex and multifactorial compression syndrome diagnosed by different medical specialities. On average 6.5 physicians of different specialities need 4.3 years to come up with the diagnosis of TOS. The correct diagnosis is of great importance and crucial for successful operative treatment. The necessary diagnostic tests can only be accomplished by team work, especially interdisciplinary cooperation. This expressly includes physiotherapy and not just the medical disciplines. This contribution presents a summary of the approaches and interactions involved in effective diagnosis and treatment of TOS.