Thoracic Outlet Syndrome

It is the entrapment and compression of the major nerve trunks (plexus) and vessels traveling from the cervical vertebrae to the arm within the narrow anatomical passage between the neck and the shoulder (subclavicular space).

Congenital presence of an extra cervical rib, neck injuries due to traffic accidents (whiplash trauma), continuously carrying heavy bags, working with hands elevated (teachers, painters), and poor/slouched posture narrow the tunnel and lead to this compression.

Nerve Compression (Neurological TOS): Represents 90% of cases. Symptoms include pain radiating from the shoulder to the hand, numbness, paresthesia (pins and needles), and weakness significant enough to drop objects.
Vascular Compression (Vascular TOS): Compression of the vein or artery. The arm swells suddenly, turns cyanotic, peripheral pulses weaken, and the limb becomes ice-cold (carrying a risk of thromboembolism).

Symptoms closely resemble a cervical disc herniation. However, in TOS patients, pain and numbness intensify within seconds when they raise their hands above their heads (combing hair, reaching for a shelf). In cervical herniation, pain is correlated more with the position of the neck rather than hyperabduction movements.

Physical maneuvers where the physician asks the patient to hold their arms elevated (such as the Roos test) are utilized to evaluate for a diminishing radial pulse. EMG is indicated for neurological assessment, while Color Doppler ultrasonography, X-rays, or MR Angiography are performed to visualize vascular compression and anomalies like an extra rib.

For neurological compression, primary management always involves targeted Physical Therapy exercises. Muscles that elevate the shoulders and clavicle are strengthened. However, if muscle atrophy has initiated in the arm despite physical therapy, or if the compressed structure is a Blood Vessel, the extra rib or muscle (scalenus) is surgically resected by Thoracic or Cardiovascular Surgery to decompress the tunnel.