Thoracic outlet syndrome is caused by compression of the brachial plexus, in most cases under the pectoralis minor muscle in the infraclavicular region of the shoulder. The hypothesis is that ultrasound imaging can be used to visualize brachial plexus compression and distortion of the pectoralis muscle during arm activity, such as abduction, and that normal subjects will not demonstrate any plexus compression or muscle distortion.

Four patients with thoracic outlet syndrome (TOS) underwent clinical exam and nerve testing to prove that they had TOS and no other nerve abnormality. They subsequently had ultrasound imaging of the shoulder (infraclavicular region) at rest and during arm abduction stress testing. Two control subjects had similar clinical exams and nerve testing to prove they did not have TOS, and then underwent similar ultrasound stress testing. The TOS patients demonstrated brachial plexus compression and pectoralis minor muscle distortion during the stress tests, and the normal subjects showed no plexus compression or muscle distortion.

INCLUSION CRITERIA:

Thoracic outlet patients must have:

• symptoms consistent with thoracic outlet syndrome, and
• no electrical testing abnormality, and
• positive arm abduction stress tests.

Normal subjects must have:

• no upper limb symptoms, or
• normal nerve testing, and
• negative arm abduction stress test

EXCLUSION CRITERIA:

Thoracic outlet patients excluded if they have:

• nerve test abnormalities, or
• negative arm abduction stress test

Normals excluded if they have:

• abnormalities on nerve testing, or
• positive arm abduction stress tests

Adult patients with upper limb symptoms of pain, numbness, tingling, or weakness, aggravated by arm abduction; Adult patients with no upper limb symptoms