The subclavian and axillary arteries pass through the thoracic outlet and provide the predominant source of blood flow to the arm. Severe or repeated compression of these arteries causes damage to the arterial wall, resulting in decreased or absent blood flow to the arm. Compression of the subclavian artery may be caused by abnormal scalene muscles or by abnormal motion of the clavicle relative to a normal first rib. Some patients have an extra rib (a cervical rib) that increases the likelihood of developing arterial TOS.

Anterior Scalene

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The subclavian and axillary arteries pass through the thoracic outlet and provide the predominant source of blood flow to the arm. Severe or repeated compression of these arteries causes damage to the arterial wall, resulting in decreased or absent blood flow to the arm. Compression of the subclavian artery may be caused by abnormal scalene muscles or by abnormal motion of the clavicle relative to a normal first rib. Some patients have an extra rib (a cervical rib) that increases the likelihood of developing arterial TOS.

Arterial TOS

The subclavian and axillary arteries pass through the thoracic outlet and provide the predominant source of blood flow to the arm. Severe or repeated compression of these arteries causes damage to the arterial wall, resulting in decreased or absent blood flow to the arm. Compression of the subclavian artery may be caused by abnormal scalene muscles or by abnormal motion of the clavicle relative to a normal first rib. Some patients have an extra rib (a cervical rib) that increases the likelihood of developing arterial TOS.

The subclavian and axillary arteries pass through the thoracic outlet and provide the predominant source of blood flow to the arm. Severe or repeated compression of these arteries causes damage to the arterial wall, resulting in decreased or absent blood flow to the arm. Compression of the subclavian artery may be caused by abnormal scalene muscles or by abnormal motion of the clavicle relative to a normal first rib. Some patients have an extra rib (a cervical rib) that increases the likelihood of developing arterial TOS.

Clavicle

Causes

Subclavian Artery

Symptoms of TOS can result from occlusion of the artery or from side effects of blood clot that forms in the aneurysm. In the first case, patients will present acutely with a cold, pulseless, pale and weak or paralyzed arm. In the second case, patients will present with ongoing episodes of tingling or abnormal sensations, with small spots in their fingers caused by tiny pieces of blood clot that break off and travel down the arm.

Symptoms

Diagnosis

Diagnosis of arterial TOS can be accomplished by several radiology tests, including invasive angiogram, CT angiogram, and MR angiogram.

Treatment

Treatment of arterial TOS is surgical, and is usually performed on an urgent basis.