[Thoracic outlet syndromes]

The thoracic outlet syndromes are clinical conditions whose true incidence is low, although they are frequently diagnosed. They are caused by compression of the brachial plexus or vascular structures due to anatomical anomalies of the cervico-axillary region.

Two main types are seen: the neurogenic syndromes and the vascular syndromes. The former make up 90% of all cases; in general these patients are women in their forties or fifties. A common initial symptom is pain along the medial side of the arm, which may be more diffuse and accompanied by paraesthesiae. Most of these patients suffer from amyotrophy and gradually progressive weakness of the intrinsic muscles of the hand, particularly the thenar eminence. The association of vascular signs and symptoms is rare. In almost all cases cervical ribs or elongated transverse aprophyses of C7 are found on plain X-ray. Characteristic changes are seen on electrophysiological studies. Treatment is surgical. This usually relieves pain and paraesthesia and stops progression of the condition to motor deficit, but has no effect on established weakness and amyotrophy.

The opinion of a neurologist is often necessary for diagnosis of neurogenic syndromes. Indication for treatment, usually surgical, should be based on an objective diagnosis.