Thoracic Outlet Syndrome

by Nate Shin, Class of 2012

The website gives basic information about Thoracic Outlet Syndrome. A more in-depth understanding of this disorder can be found with links to "Additional Web Based Resources" and "Footnotes" section below. Enjoy!

I. Description

Here is a brief video explaining this condition:

Thoracic Outlet Syndrome is an entrapment disorder that occurs inside the "thoracic outlet" which is the space between the collarbone and the first rib. There are many nerves and blood vessels and other structures that course through this area - usually between the scalene muscles down to the inferior border of the axilla - and can become compressed and cause symptoms. There are three types of TOS: neurogenic, vascular, and nonspecific. Depending on which structures are compressed, this will cause numbness or tingling down the arm, hand, and fingers, and/or pain into the neck and shoulder, among a variety of symptoms. Usually, elevating the arms can make these symptoms worse.1,2

II. Anatomy:


There are many bones, muscles, nerves, and blood vessels that course through the thoracic outlet region. However, the structures that are most often affected in this disorder include the clavicle, 1st rib, scalene muscles (anterior and middle scalene), pectoralis minor, the subclavian artery and vein, and the upper and lower brachial plexus.1

thoracic_outlet_syndrome1.jpg thoracic_outlet_syndrome2.jpg

III. Indications:

Conceptually, TOS seems like a simple disorder, but it may be hard to tell whether a patient's symptoms indicate TOS. The presentation of it is variable depending on which part of the brachial plexus or which part of the artery or vein is involved. In 98% of cases, the symptoms are neurologic. 15% of these patients may have some concomitant arterial symptoms but these arterial symptoms rarely occur alone. Most people report paresthesias (tingling or prickling), pain in the arm, and paresis (muscular weakness caused by nerve damage).3

For neurological symptoms, if the upper plexus is involved (C5 to C7), pain is reported in the neck and this may radiate into the face (sometimes with ear pain) and anterior chest, as well as over the scapula. Symptoms can also go into the lateral aspect of the forearm into the hand. If the lower plexus is involved (C7 to T1), pain and numbness occur in the posterior neck and shoulder, medial arm and forearm, and into the ulnar innervated digits of the hand. Muscles that are innervated by these nerves usually show some atrophy and weakness as well.1


Vascular symptoms usually present with coldness or edema in the hand or arm, Raynaud's phenomenon (cyanosis), fatigue and superficial vein distention in the hand. But again, vascular symptoms are rare with this condition.1


IV. Incidence/ Prevalence:

In the United States, because of the difficulty and the inaccuracy in diagnosing this condition, the statistics in this area of incidence and prevalence is lacking in general health organizations as well as the literature. It is known that this condition is more prevalent in occupations that involve bad postures of the neck and continuous use of shoulders in overhead activities. This includes secretaries, cashiers, machine operators, surgeons, and truck drivers. There is no increased incidence in athletes.4

There are some reports that say that the prevalence is about 23% of soft tissue injuries of the cervical spine. However, TOS is often misdiagnosed or overlooked, especially in the emergency department. The incidence of neurogenic or vascular TOS is considered rare with only one case per million population that is estimated for neurogenic TOS. In adults younger than 40 years, some believe that TOS is the most common cause of acute arterial occlusion in the upper limbs.4

In terms of age, this TOS occurs from the 2nd to the 8th decade with a peak in the 4th decade. In the younger age group, there is a greater likelihood for anatomic or structural abnormalities, such as an extra rib or fibrous bands.4 Females are diagnosed with this condition more often than males, with some reports saying it is a 9:1 female to male ratio with this condition. This is attributed to the difference in the shape of the chest wall. In addition, having large breasts can add to the anterior forces on the chest leading to drooped shoulder posturing and further inhibiting the thoracic outlet.5

V. Clinical Presentation

The clinical presentation of typical TOS patients are:6

  • Those with enlarged scalene muscles due to repetitive work or sporting activities: swimmers, weight-lifters and others. Also people doing lifting of objects regularly at work.
  • Young people with droopy shoulders and doing repetitive arm motions: e.g. musicians.
  • Scar tissue formation after collar bone or first rib fractures.
  • Postural problems: dropping shoulders causing traction on the brachial plexus or short stocky necks with soft tissue compressing the thoracic outlet.

A few of the symptoms that would make a physical therapist suspect this condition in any patient would be:6

  • Shoulder pain: often over the AC joint or biceps area. Not uncommonly over the back of the upper arm. A continuous burning, lame feeling in the shoulder and down the arm.
  • Tingling (pins and needles) may be felt down the arm and into the hand and often particularly into the little and ring fingers. There may be loss of control of the hand with dropping objects.
  • The pain is often present at rest eg. when driving or simply sitting watching TV etc.
  • The pain may radiate into the neck, the trapezius muscles, the shoulder blade (with a burning character), jaw, the head and even chest area.
  • Traction downwards on the arm eg. when carrying shopping bags may aggravate the sensation down the shoulder and arm.
  • Pain and discomfort is often present following activities and not only during the activities – eg. after swimming, throwing, etc.
  • Overhead activities as doing one’s hair, hanging up washing, etc., may cause a feeling of fatigue and burning in the arm, having to bring the arm down because the overhead position cannot be sustained.

VI. Potential Etiologies:

Common causes of thoracic outlet syndrome include physical trauma from a car accident, repetitive injuries from job- or sports-related activities, and certain anatomical defects, such as having an extra rib.

  • Acute neck trauma: Motor vehicle accidents (MVA) are highly associated with whiplash injuries, which is the most common mechanism causing neurogenic TOS. In a study by Sanders and Haug, more than half of the patients with neurogenic TOS developed their symptoms from an MVA. This includes the neurologic symptoms mentioned above, including pain in the neck and arms, as well as paresthesia in the hands. This can be attributed to scarring of the scalene muscles after hyperextension neck injuries, which can then compress the brachial plexus.7,8 Trauma can also cause shifting of structures in the thoracic outlet area that can lead to symptoms. Sometimes the clavicle is fractured and can compress directly on structures.
  • Repetitive stress and posture: Another likely cause is deemed to be mechanical with repetitive stress being a factor, especially in the workplace. This includes people who work at keyboards, telephones, assembly lines, or at desks for long periods of time. Small trauma to the neck muscles occur by frequently turning the neck back and forth.7 Poor posture can also cause muscle imbalances. Often, this is seen as forward head, droopy shoulders, and collapsed chest, which allows the thoracic outlet to narrow and compress the neural structures.4
  • Anatomic predispositions: Oftentimes, these "predispositions" are congenital such as bands and ligaments that are abnormally tight connecting the spine to the rib. Some people have a cervical rib, which is an extra rib located above the first rib.7 However, a study showed that in 80% of patients with cervical ribs, symptoms did not develop until after a neck injury occurred, suggesting that these anatomic variations are indeed predisposing factors and not causative factors.9 Another predisposition could be the scalene triangle (anterior and middle scalene muscles). In a study by Sanders and Roos, anatomic observations of these variations were made in cadavers and compared with similar observations on patients with TOS during surgery. Patients with TOS had more nerve roots of the brachial plexus emerging from the apex of the triangle, interdigitating fibers that put stress on the nerve roots, adherence of nerves to the anterior and middle scalene muscles, and narrower triangles.10

VII. Diagnostic Tests:


Different tests are used to elicit symptoms of TOS with positions that would compress the nerves within the anterior scalene muscle. A "positive test" for tests such as Adsons or Allens would result in the peripheral radial pulse disappearing once the patient was put into the proper test position. These tests, however, have a high false-positive response and the disappearance of the peripheral pulse does not necessarily mean that TOS exists. Adson's maneuver appears among the most effective (shown in picture above).1

Other studies show the most reliable test for TOS is the ‘‘elevated arm stress test,’’ (EAST) described by Roos. It is performed by having the patient put both arms in the 90 abduction–external rotation position, with the shoulders and elbows in the frontal plane of the chest. The patient is then instructed to open and close the hands slowly over a 3-minute period. Normally the patient can perform this stress test for 3 minutes with only forearm muscle fatigue and minimal distress. In those with an outlet syndrome, the test reproduces the usual TOS symptoms: gradual increase of pain in the neck and shoulder, aching progressing down the arm, and paresthesias developing in the forearm and fingers.3

Other various tests have also shown to compress the neural structures with certain positions as well such as the Allen's, Wright's, Halsted's, costoclavicular, and provacative elevation tests.1


A combination of tests can be used and the sensitivity and specificity of the Adson's test improves when used in combination with the hyperabduction test, the Wright's test or the Roos test. This is shown in the table below.11


One thing that cannot be forgotten are tests to rule out other conditions and injuries. This includes ROM and strength tests for neck, shoulder, and upper extremities; blood pressure of both sides; carpal tunnel syndrome; muscle spasm; cervical disc syndrome, as well as upper limb tension tests (ULTT 1, 2a, 2b, 3). 3 Radiographic tests to identify bony abnormalities and electrophysiologic [nerve conduction velocity (NCV)] tests would also allow the examiner to pinpoint the lesion in the presence of neuropathy.1

The problems with diagnosis:

VIII. Evaluation/Special Orthopedic Tests:

The PT will often do special tests to support or negate their hypothesis. The three most common special orthopedic tests are the Roos, Adsons, and Allens tests. The directions are stated and pictures shown in the videos below:

IX. Conservative Treatment:

The initial treatment for TOS is always conservative when presenting symptoms are mild to moderate in severity. Postural and breathing exercises and gentle stretching are usually the conservative treatment used by people that have this condition. This is followed by strengthening exercises for shoulder girdle muscles including the trapezius, levator scapulae, and rhomboids. Overhead exercises are avoided initially.1

Conservative treatment focuses on decreasing extrinsic pressure and reducing intrinsic irritation. By reducing inflammation in the thoracic outlet and shortening or lengthening the surrounding musculature for proper balance, pressure against the neurovascular bundle is decreased. The following are different conservative treatments for TOS:12

  • Pain and edema control:
    • Anti-inflammatory and pain medication, muscle relaxants, and therapeutic modalities (heat, transcutaneous electrical nerve stimulation [TENS], phonophoresis)
    • Trigger point injections with an anesthetic and steroid solution
    • Edema control would include edema gloves, compressive garments and sleeves, elevation, active range of motion, and retrograde massage.
  • Education:
    • Posture:
      • Bring shoulders back to a relaxed but retracted position; head should glide back automatically when shoulders are in correct position, weight should be distributed equally on both feet and low back should retain its normal lordosis. Patient may need to look in a mirror at front and side views. The patient can attempt a rigid military stance and then relax the position to improve comfort and compliance. Proper posture should be maintained when sitting, standing, or walking.
    • Ergonomics:
      • One example is sitting at a desk. If the patient works at a computer the chair height should be adjusted so that the patient’s feet rest solidly on the floor with hips and knees at a 90 angle. The spine should be supported especially at the lower back, keeping the natural curve intact. The computer monitor ideally should be positioned so that the screen is slightly below eye level and angled upward to prevent neck hyperextension. The patient should be able to look at the screen comfortably without turning or straining of the neck. If the patient stands while using the computer, one foot at a time can be propped onto a small stool to keep proper low back posture and prevent slouching.
    • Relaxation:
      • Deep breathing, mild aerobic, or contract–relax exercises are important in preventing muscle guarding around the shoulder girdle
      • Hot showers, heating pads, and massages
  • Exercises: This involves relaxing the shoulder girdle and upper trapezius musculature, stretching the scalene and pectoral muscles, and strengthening the cervical extensors, scapular adductors, and shoulder retractors.
    • Neck: chin tucks; neck side bends, rotation, flexion stretches; neck half circles
    • Shoulder: pendulum exercises; shoulder shrugs; shoulder circles; elbow pinches; doorway/corner stretch; high swings; side wings
    • Nerve gliding exercises: Nerve gliding patterns for the thoracic outlet include motions of the neck and entire upper extremity. For example, the neck bends to the right while the right elbow extends and the wrist flexes and then the neck side bends to the left shoulder while the right elbow flexes and the wrist extends. The basic concept is that while pulling on the nerve in one direction, tension in the other direction is relieved, thus gliding the nerve
    • Manual therapy and soft tissue techniques:
      • Manipulation of the scapula and thoracic outlet area is believed to be beneficial. This includes sternoclavicular joint, scapula, and the first rib articulations, acromioclavicular mobilization, and thoracic articulation mobilization
      • Deep fascial and trigger point massage release especially of the trapezius and rhomboid muscles
      • Feldenkrais method of body awareness therapy

X. Surgery & post-op treatment:

Surgical management of TOS is reserved for cases that are unmanageable to postural and exercise correction and those with vascular compromise. As with any surgery, there are inherent risks associated with TOS surgery and appropriate in-depth discussions with a surgeon should be undertaken prior to selecting this last resort treatment.

Different surgical procedures:1

  • Scalenotomy: muscle is detached from the first rib
  • Scalenectomy: removal of the scalene muscle
  • Clavicle resection: indicated primarily when the clavicle is damaged
  • Pectoralis minor release
  • First rib resection
  • Cervical rib resection

When scalenectomy, with or without first rib resection, is the surgical approach used, its 5-year success rate is about 70%.13

Most common anatomic approaches:1,2

  • Anterior supraclavicular approach: This approach repairs compressed blood vessels. Your surgeon makes an incision just under your neck to expose your brachial plexus region. He or she then is able to look for signs of trauma or may discover fibrous bands contributing to compression near your first (uppermost) rib and can repair any compressed blood vessels.
  • Transaxillary approach: In this surgery, your surgeon makes an incision in your chest to access the first rib, then removes a portion of the first rib to relieve compression. The advantage of this type of surgery is that it gives the surgeon easy access to the first rib without disturbing the nerves or blood vessels. But it also means the surgeon has limited access to the area's nerves and vessels, and most fibrous bands and cervical ribs that may be contributing to compression are hidden behind these nerves and blood vessels.

After surgery, 70% of cases have a good or excellent response using a supraclavicular or transaxillary resection of the first rib. Improvement in pain symptoms ranges from 70% to 80%, some patients require occasional analgesics, and 10% note no improvement. In individuals with signs and symptoms and electrophysiologic changes consistent with classic TOS, no improvement in strength is noted when atrophy was present before surgery.14 However, a 4-year follow-up reported no significant difference in return to work or symptom severity when the first rib was resected compared to a conservative, nonoperative approach.15

Post-Op Treatment:16

A general guideline for treatment after surgery for thoracic outlet syndrome

  • Postoperative Day 1 (week 1): gentle range of motion, active and active-assisted range of motion; drain removal at approximately 3–5 days
  • Postoperative Day 8 (week 2): suture removal; continue gliding exercises for neck and upper extremity
  • Postoperative Day 15 (week 3): scar massage, scar desensitization
  • Postoperative Day 22 (week 4): phonophoresis to scar site, brachial plexus massage, start strengthening exercises
  • Postoperative Day 29 (week 5): upgrade strengthening exercises
  • Postoperative Day 36 (week 6): ergonomic training, work-simulated activities
  • Postoperative Days 43–83 (weeks 7–12): work hardening

XI. Modalities:

Modalities can play a key role in both conservative and post-operative treatments of TOS. It is not used as a sole method of treatment but is often used in combination with other treatments, such as postural and ergonomic education, stretching, strengthening, and nerve gliding exercises.

For conservative treatment:12
A conservative routine is suggested to continue for 4-6 months before surgery is considered. During this time, modalities are utilized mainly for pain control, edema control, and relaxation.

  • Pain control: (in addition to anti-inflammatory and pain medication, muscle relaxants):
    • Heat (before exercise and ice afterwards)
    • Transcutaneous electrical nerve stimulation (TENS)
    • Microcurrent and cranial electrotherapy stimulation
    • High voltage pulsed current
    • Phonophoresis (ultrasound)
  • Edema control: (in addition to edema gloves, compressive garments and sleeves, elevation, AROM, retrograde massage)
    • Phonophoresis treatments (ultrasound with steroid gel) – also potentially helps control inflammation and scar contraction.
  • Relaxation: (in addition to deep-breathing, mild aerobic, or contract-relax exercises)
    • Heating pads, hot showers (cold temps should be avoided, can irritate TOS symptoms)

For post-operative treatment:16
Postoperatively, there is more of an emphasis of modality use on wound care, edema control, and scar management while also incorporating nerve gliding and ROM exercises.

  • Wound care:
    • Ice as tolerated for 10-minute periods, on and off for the first 3-4 days
  • Scar management (begins 24-48 hrs after sutures have been removed):
    • Phonophoresis with triamcinoline gel (0.3%) begins at 3 weeks over the scar site and brachial plexus (can also extend to upper trapezius in the event muscle tightness is noted)
  • Pain management:
    • TENS (pads can be placed along the injured nerve pathways of the injured extremity or over upper trapezius)
    • Heat is recommended before exercises (after initial inflammatory period) and ice after the exercise program

XII. Additional Web Based Resources:

A series of links to appropriate web sites to learn more about this condition.

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