The subclavian artery study must instead be carried out at the level of the 'inter-scalene triangle' which is delimited inferiorly by clavicle, medially by anterior scalene muscle and laterally by middle scalene muscle. Ĭolor Doppler US of the subclavian vein must be performed at the level of the 'costal-clavicular space', where compression occurs, which is delimited below by first rib, above by clavicle and anteriorly by anterior scalene muscle. 3) Color Doppler US and Duplex Doppler US for the flowmeter study. The Ultrasound examination must be performed using both B-Mode Ultrasound (US) for the scalene muscles and cervical ribs morphological study (Fig. Generally, by raising the arms to 90°, the arterial and/or venous compression appears or accentuates and with them the symptomatology. The Ultrasound is the first-level examination and must be performed with arms raised to 90° and arms lowered (Adson test), to measure the changes in the caliber and flow of the artery and subclavian vein. The imaging is entrusted to Standard Radiography to ascertain the presence of the cervical ribs and to ultrasound for the study of vascular alterations. The diagnosis of TOS can be clinical: Adson test, Allen test, Wright test, Halstead maneuver, and/or instrumental. If compression is caused by hypertrophy of the scalene muscles, it always involves the subclavian vein and causes venous stasis with hypertension, cyanosis, swelling (often in the morning), and pain in the upper limbs. The cervical rib can compress both the brachial plexus (neurological form) with tingling and/or paresthesia, and the subclavian artery (vascular form) with consequent hypo-perfusion and cyanosis of the upper limb. The subclavian artery is almost always compressed by the cervical rib, while the subclavian vein by hypertrophy of the anterior scalene muscle. 2a), while compression of the subclavian artery at the level of the 'inter-scalene triangle' (Fig. In TOS, for anatomical reasons, compression of the subclavian vein always takes place at the 'cost-clavicular space' (Fig. The incidence of the disease is higher in females aged between 20 and 50. Very rare is the combination of bilateral compression of the artery and subclavian vein, due to the coexistence of two cervical ribs and bilateral hypertrophy of the scalene muscles. TOS can therefore be bilateral, due to the presence of two cervical ribs and/or to bilateral hypertrophy of the scalene muscles. The cervical rib is a congenital alteration, often asymptomatic, while hypertrophy of the scalene muscles is generally acquired, frequent in some sports that involve the shoulder muscles. 1b) or by hypertrophy of the scalene muscles. Thoracic Outlet Syndrome (TOS) is a rare pathology of neuro-vascular compression caused by the bilateral (Fig.

Arterial doppler ultrasound