The term thoracic outlet syndrome (TOS) defines neuro-vascular disorders produced in the upper extremities due to the external compression of the brachial plexus, subclavian artery and vein (neurovascular bundle) within the thoracic outlet. Thoracic outlet syndrome may be produced by bone malformations, fibromuscular anomalies, neck, and shoulder injuries, and postural defects. Clinical symptoms of this syndrome are diversified. However, neurological disorders are diversified. However, neurological disorders are prevailing. Thoracic outlet syndrome is two-fold more frequent in women than in men, especially in the period of physiologic descent of the shoulder girdle. Clinical diagnosis is based mainly on physical examination. Doppler segmental blood pressure measurements, limb oscillography, rheography, X-ray of the neck and brachial girdle, arteriography, intravenous digital subtraction angiography, phlebography of the limbs, and nerve conduction studies are being used to confirm the diagnosis. Differential diagnosis should consider cervical discopathy and carpal tunnel syndrome. The treatment is usually conservative by means of physiotherapy. Carefully planned, prolonged conservative therapy (for months) produces favourable effects in the majority of cases. Patients with severe symptoms of the thoracic outlet syndrome should be treated surgically. Surgery is being successful in 80% of cases.