Although the history of patients with TOS is often nonspecific, physical examination is diagnostic in up to 97 % of patients (Rayan 1998). Physical examination should begin with observation of the patient’s habitus and assessment of any visible asymmetry. Slouching, shoulder droop, and scapular asymmetry are clues that may lead to a diagnosis of TOS but could also represent alternative pathologies. The skin over the chest wall, neck, and shoulder girdle should be examined for the presence of venous engorgement or collateral sprouting. Muscle tone and bulk should be evaluated via palpation with and without resistance, especially in the neck, upper back, shoulder, arm, forearm, and hand. A sensory examination should be performed utilizing two-point discrimination and Semmes-Weinstein monofilaments, as well grip and pinch measurements. Blood pressure measurements in both arms, as well as auscultation of the subclavian arteries, should be performed to assess for thromboembolism or aneurysm. In a study by Braun and colleagues, pulse oximetry measurements in patients with symptomatic TOS were compared with measurements taken in a control group prior to and after a provocative maneuver. Oxygen saturation dropped to 86 % in the symptomatic TOS group while only dropping to 94 % in the control group. Therefore, it was concluded that pulse oximetry may be a quick and inexpensive tool to aide in the diagnosis of thoracic outlet syndrome (Braun et al. 2012).

The hallmark of the physical examination for thoracic outlet syndrome is the performance of provocative tests. Positive results are documented if a maneuver either reproduces the patient’s symptoms or diminishes/obliterates the radial pulse. Several historically utilized maneuvers such as Adson’s, Wright’s, and Halstead’s tests are less commonly performed due to their lack of sensitivity and specificity for TOS (Gillard et al. 2001).

The Roos’ test (90° abduction external rotation test, stickup test, elevated arm stress test [EAST]) involves the patient holding the affected arm in an abducted and externally rotated position while repeatedly pumping the hand open and closed for 3 min. Symptoms and rapid fatigue are indicative of a positive test. The test may be poorly tolerated in patients with positional nerve compression. This maneuver is often considered the most sensitive test for thoracic outlet syndrome (Roos 1990).

The upper limb tension test involves the patient elevating both arms out to the sides with elbows straight and head facing forward. The patient’s wrists are then extended, and the head is tilted away from the affected side. When this test is positive, the patient reports increasing discomfort or paresthesias due to the increasing tension on the brachial plexus (Sanders et al. 2007).

Several imaging modalities may be utilized in the workup of thoracic outlet syndrome. Initial radiographs of the cervical spine and chest should be obtained at the time of first evaluation to assess for the presence of an elongated C7 transverse process or cervical rib on the affected side (Wilbourn 1999; Fig. 3). Fibrous bands associated with abnormal cervical ribs are radiolucent and therefore are better visualized on MRI (Panegyres et al. 1993).

Ultrasonography is often utilized in patients with vascular pathology due to its low cost and ease of use. Color duplex ultrasonography is highly sensitive and specific when diagnosing stenosis, occlusion, and/or flow abnormalities (Demondion et al. 2006; Wadhwani et al. 2001). Pulse volume recordings can be used to evaluate arterial compression and can be followed up by MR angiography or arteriography (Kleinert and Gupta 1993).

Angiography provides the best visualization of the arterial anatomy and is considered the gold standard for the diagnosis of arterial TOS. MR angiography is noninvasive, but conventional angiography allows for simultaneous therapeutic thrombolysis in an acute scenario (Ohkawa et al. 1992; Sharafuddin et al. 2002). The bony anatomy should be carefully assessed, as bone anomalies are the most common cause of arterial compression.

In cases of suspected venous TOS, venography is the gold standard. The patient may be asked to perform a provocative maneuver while imaging takes place, as this may be diagnostic for venous compression from TOS. As with angiography, thrombolysis can also be achieved during venography if necessary. Additionally, collateral vein sprouting may be visible on venography (Sharafuddin et al. 2002).

Electrodiagnostic evaluation is recommended in patients with suspected neurogenic TOS as part of the initial workup. In patients with symptomatic neurogenic TOS, electromyographic (EMG) changes showing chronic denervation of the intrinsic hand muscles are the initial abnormalities observed, while nerve conduction velocity changes are not seen until late in the disease (Marcaud and Métral 2000; Passero et al. 1994).

A scheme was introduced by Roos that classified TOS based on the affected segment(s) of the brachial plexus. These categories include upper trunk compression, lower trunk compression, and combined compression. Eighty-five to ninety percent of his patients exhibited symptoms of lower trunk and/or combined compression (Roos 1982).

Wilbourn categorized thoracic outlet syndrome into two basic types, each with two subtypes (Wilbourn 1999). Vascular TOS is subdivided into arterial and venous, while neurogenic TOS is subdivided into true, or electrically positive, and disputed, or electrically negative.

There are no validated outcome measures to specifically assess thoracic outlet syndrome outcomes. Several quality of life scores, including the Cervical Brachial Symptom Questionnaire (CBSQ), the Brief Pain Inventory (BPI), and the Short-Form 12 (SF-12), have been utilized to evaluate long-term TOS outcomes following operative intervention. Additionally, functional outcomes following surgical repair of TOS have been measured utilizing the Disability of Arm, Shoulder, and Hand (DASH) score (Rochlin et al. 2012, 2013).

Nonoperative management is universally agreed upon as the first-line treatment of thoracic outlet syndrome. The goal is to alleviate the compression of the thoracic outlet as well as avoidance of exacerbating factors (Leffert 1992; Novak et al. 1993; Table 1).