Evaluation and Treatment for Thoracic Outlet Syndrome

Evaluation and Treatment for Thoracic Outlet Syndrome

Tests can be effective in diagnosing this sometimes confounding condition

Thoracic outlet syndrome (TOS) is a collection of syndromes resulting from abnormal compression of the brachial plexus and/or the subclavian artery/vein (neurovascular bundle) that occurs between the cervical spine and the axilla. Symptoms of TOS may include upper extremity pain, paresthesias, numbness, muscle weakness, sensation of heaviness, discoloration, edema, arm fatigue, ulceration and gangrene.1,2 Symptoms will vary according to the severity of the compression. Other clinical terms used to describe this presentation include the scalenus anticus, costoclavicular, hyperabduction, pectoralis minor and cervical rib syndromes.3


The thoracic outlet is the triangular shaped channel through which the nerves and vessels of the arm leave the neck and thorax.3 The subclavian artery and brachial plexus arch over the first rib between the anterior and middle scalenes, then pass under the clavicle and subclavian muscle, then travel under the pectoralis minor muscle and into the axilla. The subclavian vein travels the same course except it passes anterior to the anterior scalene muscle.2

Causes of Compression

Compression sites generally include the interscalene triangle, costoclavicular space, or pectoralis minor muscle. The neurovascular compression can result from a variety of causes (see Table). Women are generally more affected than men by the disorder. It should be noted that the cervical ribs are present in less than 0.5 percent of the population and symptomatic in only 5 percent to 10 percent.3 Fibrous bands that extend between cervical vertebrae and the first rib may also be a source of compression. Middle-aged women with sagging shoulders or obese, full-figured women are more prone than others to develop TOS. Because TOS can stem from a variety of causes, a detailed patient evaluation is important.

TABLE: Contributing Factors for TOS
1. Structural/Bony
a. Accessory cervical rib
b. Bifid clavicle
c. Abnormalities of first rib
d. Cervical fibrous bands
e. Cervicodorsal scoliosis
2. Soft Tissue/Muscular
a. Tight or hypertrophied scalenes
b. Tight pectoralis minor
c. Subclavian artery may bifurcate one of scalenes
d. Constant respiratory movement with respiration
e. Obesity and/or breast hypertrophy
f. Tight or weak postural muscles
3. Postural
a. Depressed and retracted clavicles (military posture)
b. Sagging or drooping shoulders
c. Forward head and shoulder posture
d. Repetitive positioning of arms overhead (shoulder elevation and hyperabduction)
e. Constant muscle tension in the shoulder girdle (carrying heavy loads)
4. Occupations
a. Static positions (secretaries, computer operators, bench workers, assembly line workers, cash register operators)
b. Hypertrophic musculature (weightlifters, jack hammer operators)
c. Repetitive overhead arm positioning (electricians, painters, carpenters, tennis players, baseball pitchers, volleyball players)
5. Traumatic
a. Clavicular fracture
b. Humeral head dislocations
c. Brachial plexus injuries

Patient Evaluation

The evaluation of any patient includes a careful history and detailed physical examination. Patient complaints may include pain and paresthesias of the neck, shoulder, arm, forearm and hand (usually in the C8-T1 dermatome). Pain is typically worse after overhead arm use and at night.4 Vascular symptoms may include a feeling of heaviness in the arm or hand, deep ache in the neck and shoulder region, easily fatigued arms/hands, swelling or puffiness in the arm or hand, bluish discoloration or coldness and superficial vein distention in the hands.

Neurological symptoms include C8-T1 dermatome paresthesia, muscle weakness and atrophy of intrinsic muscles of the hand, forearm muscle cramping, pain in the arm and hand and paresthesias of the neck, shoulder, arm and hand. The examiner should obtain a thorough description of the patient’s work station, physical and positional job requirements, home/leisure activities and any precipitating injury. This provides valuable information regarding postures or activities that may contribute to the problem.

After performing a thorough subjective evaluation, the clinician must perform a detailed objective examination. The physical examination should include posture, palpation, muscle flexibility, muscular strength, joint tissue mobility, sensation, reflexes, respiratory patterns and neural tension tests.

During the postural evaluation, head and shoulder posture should be especially noted and should include inspection of the scapulae and clavicles as positioned on the thorax. Postural variations such as forward head or rounded shoulders may lead to muscle tightness of levator scapula, scalanes, suboccipitals and pectoralis minor.1Palpation of the scalenes, cervical musculature, upper trapezius, pectoralis minor and periclavicular region should reveal any musculature or tissue that is tender, tight or in spasm. Cervical range of motion, shoulder range of motion, pectoralis minor flexibility, scalene flexibility and upper trapezius flexibility should be noted.

Mobility of the clavicle, first rib, cervical spine and upper thoracic spine should also be inspected. Strength testing of the cervical spine, scapular musculature and upper extremity musculature may provide important information regarding weakness of the postural muscles and/or weakness that relates to specific upper extremity myotomes. Sensation and reflex testing should be noted. Respiratory patterns that continually use the action of the scalene muscles to elevate the first rib should be inspected as this can lead to hypertrophy of these muscles.1 Upper extremity neural tension tests can be utilized to reproduce the patient’s symptoms, however, these tests may be unreliable because positional compression of the neurovascular structures is a common phenomenon in normal subjects.5

Traditional special tests for TOS that are to reproduce the symptoms include Roo’s test, Adson’s test, costoclavicular test, Halstead maneuver, Wright test and Allen maneuver. With each test except Roo’s test, the examiner palpates the radial pulse. 1. Roo’s test: The patient stands and abducts shoulders to 90 degrees, externally rotates the shoulders, and flexes the elbows to 90 degrees. The patient then opens and closes the hand slowly for three minutes. The test is positive if the patient is unable to complete the test or experiences heaviness, numbness, tingling or pain.6

2. Adson’s test: The examiner locates the radial pulse while arm is held in extension, external rotation and slight abduction. The patient is instructed to take a deep breath and turn head toward the test arm while extending the neck. If there is compression, the radial pulse will be diminished or absent.6,7 The goal of this test is to tense the anterior and middle scalenes.

3. Costoclavicular test: The examiner palpates the radial pulse and then draws the patient’s shoulder down and back. If the pulse disappears, the test is positive.6 The goal of this test is to provide compression of the costoclavicular space.

4. Halstead maneuver: The examiner palpates the radial pulse and applies downward traction on the test extremity while the patient’s neck is hyperextended and rotated to the opposite side. Absence of the pulse indicates a positive test.6

5. Wright test (hyperabduction test): The examiner palpates the radial pulse and hyperabducts the arm so the hand is brought overhead with the elbow and arm in the coronal plane. The patient takes a deep breath and may rotate or extend the neck for additional effect.6

6. Allen maneuver: The examiner palpates the radial pulse while positioning the shoulder in external rotation and horizontal abduction. The patient then rotates the head away from the test side.6

Adson’s test has generally been the most commonly performed special test for TOS, but recent literature has found this test to be positive in asymptomatic individuals.3 It should, therefore, not be used as an exclusive indicator but in conjunction with other objective findings.

The diagnosis of TOS should be based on clinical findings as well as exclusion of other pathologies such as cervical disc disease, nerve root impingement, peripheral nerve compression, myofascitis of the upper back, cervical radiculopathy, reflex sympathetic dystrophy, brachial neuritis, cervical spondylosis, carpal tunnel syndrome and shoulder impingement. Other special tests should be performed to rule out other pathologies of the neck, shoulder or upper extremity. Diagnostic testing for TOS may also include thermography,8 magnetic resonance imaging of the brachial plexus,5 nerve conduction velocity testing, doppler studies, venography, arteriography and radiographs.


Physical therapy treatment should address the problems identified during the patient evaluation. Conservative treatment should be utilized unless there is significant vascular compromise, motor loss or as long as the patient is improving.8 Surgical treatment typically includes resection of first rib, scalenotomy or clavicular resection, but should be used as a last resort.

Physical therapy treatment should be specifically directed to the structures involved and the treatment program should be persistent. The treatment goal should be to increase the space of the thoracic outlet and reduce the pressure upon the nervous and vascular structures.3 The conservative treatment program should include the following basic principles.

  1. Postural correction/modification;
  2. Stretching tight musculature/relieving muscle tension;
  3. Increasing the mobility of the first/second ribs and clavicle;
  4. Strengthening weak muscles;
  5. Diaphragmatic breathing and relaxation instruction.3

Posture Instruction. The most important aspect of treatment includes correction of postural faults. Patients must be conscious of their posture during work, sleep and daily activities. Postural positions that may compress the neurovascular bundle include forward head, forward and depressed shoulders and static overhead positioning of arms (such as during sleep). If a patient complains of upper extremity symptoms or pain that occurs at night after arms unconsciously become positioned overhead, the therapist may suggest that the patient loosely attach the arm at the wrist to pants or gown. Patients should be told to avoid sleeping in prone or on the affected side. Postural exercises may include cervical retraction, scapular retraction and strengthening of postural muscles.

Modalities. Modalities such as ultrasound, moist heat or electrical stimulation may be incorporated into the treatment for pain reduction and to assist with relaxation of muscular tension or tightness.

Manual therapy. Massage/soft tissue mobilization of the upper trapezius, scalenes, cervical paraspinals, levator scapulae and rhomboids is beneficial for relieving muscular tension or tightness. Joint mobilization of the sternoclavicular (SC) joint, acromioclavicular (AC) joint, scapulothoracic joint, cervical spine and first/second ribs is needed for restoring accessory joint motions. SC and AC joints are mobilized using an anteroposterior and craniocaudal sheer of the clavicle. The first and second ribs can be mobilized in prone (with the head rotated toward but sidebent away from the side being treated) as the therapist applies pressure mediocaudally over the angle of the first rib. This posterior mobilization should be followed by an anterior mobilization (with the patient positioned supine) directed at the sternocostal junctions of the first and second ribs.2

Once accessory joint mobility is restored, the therapist can perform manual stretching or myofascial release techniques to the scalenes, pectoralis minor and major, suboccipitals, levator scapula and upper trapezius. Scapular mobilization may be indicated depending on the patient’s scapular mobility. If a cervical lesion is noted during the evaluation and is felt to contribute to scalene or pectoral muscle spasms, manual cervical traction or cervical mobilizations may relieve nerve root irritation. Other manual therapy techniques may include Jones strain/counterstrain, positional release or CranioSacral Therapy.

Strengthening exercises. Strengthening exercises for the lower scapular stabilizers should be done initially in a gravity assisted position to permit correct recruitment of the muscles and minimize assistance from the scapular elevators.4 However, if the patient presents with drooping shoulders, scapular elevation exercises may be beneficial using a graduated program. Emphasize muscle endurance and maintenance of postural correction, rather than strength.4

Home exercise program. Instruction in a home exercise program is of extreme importance to empower the patient and teach him how to help with management of the problem. If muscle, soft tissue or joints restrict movement, appropriate stretching exercises should be given. These exercises may include stretching for levator scapula, pectorals, upper trapezius, suboccipitals and sternocleidomastoid. Exercises for strengthening the lower scapular stabilizers and for cervical/scapular kinesthetic training should be included.1 If the patient demonstrates faulty respiratory patterns, diaphragmatic breathing and relaxation exercises will be beneficial.1 The patient should also be instructed to avoid positions and postures that compromise the neurovascular bundle. Emphasis must be placed on the patient’s independence and compliance with the home exercise program.

Activity modification/patient education. Patient education regarding postures, positions and activities that exacerbate the symptoms is of extreme importance to allow the patient to begin modification of work and home activities. The patient should minimize overhead activity, be conscious of head/shoulder postures, avoid sleeping in prone or on the affected side and avoid carrying heavy objects with the affected arm.


Physical therapists have an important role in the treatment of patients suffering from TOS. A thorough patient evaluation is of extreme importance to identify the problematic tissue and structures contributing to the patient’s complaints. The initial treatment of choice is physical therapy that emphasizes postural correction, manual techniques, appropriate stretching and strengthening exercises and modification in daily activities.


  1. Kisner, C., & Colby, L.A. (1996). Therapeutic exercise-Foundations and techniques. Philadelphia: F.A. Davis.
  2. Lord, J.W., & Rosati, L.M. (1971). Thoracic outlet syndromes. Clinical Symposia, 23 (2), 2-5. Jackson, P. (1987). Thoracic outlet syndrome: Evaluation and treatment. Clinical Management, 7(6), 6-10.
  3. Novak, C.B., Collins, E.D., & MacKinnon, S.E. (1995). Outcome following conservative management of thoracic outlet syndrome. The Journal of Hand Surgery, 20(4), 543-547.
  4. Lindgren, K.A., Manninen, H., & Rytkonen, H. (1995). Thoracic outlet syndrome-A functional disturbance of the thoracic upper arperture? Muscle and Nerve, 18, 526-530.
  5. Magee, D.J. (2002.) Orthopedic physical assessment. Philadelphia: W.B. Saunders Company.
  6. Hoppenfeld, S. (1976). Physical examination of the spine and extremities. Upper Saddle River, NJ: Prentice Hall.
  7. Sucher, B.M. (1990). Thoracic outlet syndrome-A myofascial variant: Part 1. Pathology and Diagnosis. JAOA, 90(8), 686, 703.