Spurling’s test [5] is performed by bending the neck laterally towards the affected shoulder. The examiner then applies a downward axial force (classically, ~7 kg) to the top of the head, thus narrowing the space for cervical nerve roots to exit the spinal cord (Fig. 10.4). Reproduction of neck and shoulder pain with this maneuver is suggestive of a cervical nerve root lesion. Other authors have suggested various modifications to Spurling’s original test, such as the addition of rotation and/or extension prior to applying a downward pressure to the top of the head [3]. L’hermitte’s sign, which also indicates cervical spine pathology, occurs when a “shooting” or “electric-like” pain propagates down the neck and down the ipsilateral arm with rotation or flexion of the neck without application of an axial load. Although a few studies have evaluated the validity of L’hermitte’s sign, these studies appear to have significant methodological flaws that hinder interpretation of their results [6, 7]. Thus, the value of L’hermitte’s sign to detect cervical spine pathology remains anecdotal at best.

Shah and Rajshekhar [8] studied the reliability of Spurling’s test in the diagnosis of cervical disc disease with the reference standard of magnetic resonance imaging (MRI) in 25 patients who were treated nonoperatively and direct visualization at surgery in 25 patients who were treated operatively. The test was performed by extending and laterally bending the neck and then applying an axial load to the top of the head. The investigators did not rotate the head prior to application of an axial load. The sensitivity and specificity of Spurling’s test was found to range between 0.90 and 1.00, depending on whether MRI or surgery was used as the reference standard. In contrast, Wainner et al. [9] performed the same test; however, they also rotated the head towards the ipsilateral side before applying an axial load. In that study, they used electromyography (EMG) as the reference standard. The investigators calculated a sensitivity of 0.50 and a specificity of 0.93 for this version of Spurling’s test. In addition, Tong et al. [10] calculated an even lower sensitivity (0.30) when rotating the neck towards the contralateral shoulder. Combining the results of these three studies, it appears that lateral rotation of the neck decreases the sensitivity of the test for the detection of cervical radiculopathy. This rationale is supported by Anekstein et al. [11] who found the greatest sensitivity with the combination of lateral bending and extension without rotation. Thus, we prefer to perform the Spurling’s test in neutral rotation to improve diagnostic efficacy.

The shoulder abduction test is performed by simply having the patient abduct the humerus such that the hand is placed on the top of the head (Fig. 10.5). This maneuver is thought to increase the space available for the cervical nerve roots to exit the spinal cord, thus diminishing symptoms. A cadaveric study by Farmer and Wisneski [12] confirmed the theoretical rationale for the test. In their study, pressure transducers were placed within cervical foramina and pressure readings were recorded with the humerus and the neck in various positions. They found that extension of the neck produced the greatest intra-foraminal pressure while abduction of the humerus decreased this pressure, thus further solidifying this maneuver as a viable technique for the detection of cervical nerve root compression. Wainner et al. [9] later found that this maneuver was 17 % sensitive and 92 % specific for the detection of cervical spine-related pathology.

Farshad and Min [13] recently described an abduction extension test that was reported to have a sensitivity of 0.79 and a specificity of 0.98 in the detection of cervical nerve root compression. This test was performed by laterally abducting the humerus to 80° with the neck rotated towards the contralateral shoulder. With the patient in this position, an anteriorly directed pressure was applied to the posterior aspect of the humeral head (Fig. 10.6). Reproduction of symptoms was considered a positive test. In their preliminary cadaveric study using this maneuver, nerve roots were displaced by approximately 4–5 mm in all cases, potentially explaining the resulting high sensitivity and specificity values.

The Valsalva maneuver is performed with the patient in the seated position. The patient is then asked to take a deep breath and to “bear down” against a closed glottis for 2–3 s. This technique increases intra-abdominal pressure which, in turn, increases pressure within the thecal sac. The test is positive for cervical radiculopathy when neck and shoulder symptoms are reproduced. Wainner et al. found the sensitivity of this test to be only 0.22; however, the specificity was 0.94. Therefore, it is suggested to combine this test with a more sensitive test, such as Spurling’s test or the upper limb tension test (described below), to improve diagnostic accuracy.

The cervical distraction test is performed with the patient in the supine position. The examiner cradles the jaw and occiput with their hands and slightly flexes the neck to improve patient comfort. A distraction force is applied gently and gradually until significant resistance is felt (classically, ~14 kg of force) (Fig. 10.7). This maneuver is thought to increase the space available for exiting nerve roots. Relief of symptoms indicates a positive test and is indicative of cervical pathology. Wainner et al. [9] determined that the cervical distraction test was 44 % sensitive and 90 % specific for the detection of cervical spine pathology. Similarly, Viikari-Juntura [3] calculated a sensitivity of 0.44 and a specificity of 0.97. Thus, similar to the Valsalva maneuver mentioned above, it is important to combine this test with other, more sensitive provocative maneuvers to improve diagnostic efficacy.

The brachial plexus tension test was first described by Elvey [14] in 1986 and has been modified on a few occasions [9, 15]. Although less descriptive, some researchers refer to this maneuver as the “upper limb tension test.” The test is performed as a series of steps with the patient in the supine position. The first step is to place the hand over the posterior aspect of the scapula and to depress the scapula against the thoracic wall. Sequentially, the shoulder is then abducted, the forearm is supinated, the wrist and fingers are extended, the humerus is externally rotated, the elbow is extended, and the neck is bent towards the contralateral side and then towards the ipsilateral side (Fig. 10.8). Reproduction of the patient’s symptoms was considered a positive test. Wainner et al. [9] found that the sensitivity and specificity values for this test were 0.97 and 0.22, respectively. Quintner [15] found slightly lower sensitivity and specificity values; however, they used cervical radiography to confirm the diagnosis as opposed to EMG which was performed by Wainner et al. [9].

As an adjunct to this test, Wainner et al. [9] proposed a second method to evaluate for cervical spine pathology. In this maneuver, the patient was positioned supine with the shoulder abducted to 30°. The examiner then sequentially depressed the scapula, internally rotated the humerus, extended the elbow, flexed the wrist and fingers and, finally, contralateral followed by ipsilateral side-bending of the neck (Fig. 10.9). Reproduction of the patient’s symptoms was considered a positive test. The sensitivity and specificity values for this maneuver were 0.72 and 0.33, respectively, representing an inferior result compared to Elvey’s original test described above.

As the brachial plexus and subclavian vessels course towards the axilla and the upper arm, there are at least four areas of potential narrowing that can result in TOS. The first potential site of compression occurs in patients with a congenital bony or fibrous extension of the transverse process of the seventh cervical vertebra (cervical rib; Fig. 10.10) [18, 19]. The interscalene triangle is the second of these stenotic areas and is the most common site of compression (scalenus anticus syndrome; Fig. 10.11). The interscalene triangle is bordered by the anterior scalene muscle anteriorly, the middle scalene posteriorly, and the superiomedial aspect of the first rib inferiorly. The subclavian artery, subclavian vein, and the trunks of the brachial plexus are located within this triangle and is thus a potential site of neurovascular impingement. The costoclavicular space is the third site of narrowing and is located between the middle 1/3 of the clavicle and the first rib (costoclavicular syndrome; Fig. 10.12). Impingement in this area primarily involves the subclavian artery and/or vein. The fourth potential site of neurovascular compression is within the subcoracoid space in an area beneath the pectoralis minor muscle-tendon unit (pectoralis minor syndrome; Fig. 10.13).

The numerous potential etiologies for TOS can be divided into static and dynamic causes. Static causes might include cervical ribs, fracture callus, fibrous bands, anomalous or fibrotic musculature (such as pectoralis minor syndrome [20, 21]), poor posture, and pathologic lesions with significant mass effect such as a Pancoast tumor, tuberculosis, or osteomyelitis. Reproduction of symptoms with scapulothoracic or glenohumeral motion typically indicates a dynamic cause which can occur within any of the three typically stenotic areas mentioned above. Repetitive microtrauma, as which occurs commonly in athletes and manual laborers, can also play an important role in the pathogenesis of TOS; however, the exact pathomechanism behind repetitive microtrauma and the development of TOS has not been clearly defined [21, 22].

The potential causes of TOS can also be divided by the structure involved. Neurogenic TOS, which has been reported to account for more than 95 % of all cases of TOS [23], involves compression of the nerves within the brachial plexus and is often the result of neck trauma. Vascular TOS, as the name suggests, involves compression of the subclavian artery and/or vein. Compression of the subclavian artery is typically associated with a cervical rib or rudimentary first rib [24, 25] (see Fig. 10.10). In contrast, compression of the subclavian vein usually occurs within the costoclavicular space [26] (see Fig. 10.12). Mixed TOS is more nonspecific and may involve compression of nerves, arteries, and/or veins simultaneously with varying magnitudes of compressive force.

Many patients with TOS report an aching sensation over the shoulder or neck accompanied by upper limb paresthesias such as numbness or tingling. Sensory dysfunction of the arm and/or hand often occurs simultaneously with occipital headaches. Compression of the subclavian vein may result in ipsilateral swelling and/or discoloration of the arm whereas compression of the subclavian artery can produce a subclavian bruit. Cold, pale skin distal to the elbow may indicate proximal compression of a sympathetic nerve. In reality, however, most patients with TOS present with vague symptoms that are often difficult to differentiate from other causes of shoulder pain.

It is important to inspect the entire upper extremity, including the intrinsic muscles of the hand, for muscle atrophy, wasting, or fasciculations since these may suggest the presence of a neuropathy or myelopathy. Hoffman’s sign is a useful test for the detection of cervical myelopathy (Fig. 10.14). Combined supraspinatus and infraspinatus atrophy can occur since innervation for both of these muscles is derived from the C5 nerve root of the brachial plexus (suprascapular nerve). Weakness or atrophy of the rhomboid musculature may indicate compression of the dorsal scapular nerve (also from the C5 nerve root). The radial, median, and ulnar nerves are also derived from the brachial plexus, and care must be taken to evaluate the appropriate musculature to potentially locate the site of impingement. Tinel’s sign should also be performed to rule out cubital tunnel syndrome at the elbow and carpal tunnel syndrome at the wrist.

There are several provocative maneuvers that can be used to help determine the site of impingement and the structure involved in TOS. However, interpretation of clinical tests for TOS is controversial and there is no individual test that is universally diagnostic. This is due to the wide variation in potential pathomechanisms involved with its development. In addition, the high false positive rate for many of these tests calls to question their application in clinical practice [27, 28]. Rayan and Jensen [27] found that 91 % of asymptomatic subjects developed symptoms from at least one of the tests designed to detect TOS.

There are numerous potential etiologies of axillary nerve palsy, many of which occur as a result of blunt trauma, iatrogenic injury, or nerve compression. The axillary nerve branches from the C5–C6 nerve root and courses towards the quadrilateral space, passing just inferior to the subscapularis and anteroinferolateral to the inferior glenoid rim. The quadrilateral space, as the name suggests, is bordered by four structures—namely, the teres minor superiorly, the teres major inferiorly, the proximal humerus laterally, and the long head of the triceps medially (Fig. 10.20). The posterior circumflex humeral artery, a branch of the axillary artery, travels with the axillary nerve through the quadrilateral space. Compression of the neurovascular bundle within this space, termed the “quadrilateral space syndrome” by Cahill and Palmer [46] in 1983, can occur from anomalous fibrous bands, traumatic scarring, mass lesions, glenolabral cysts, large humeral head osteophytes, and/or muscle hypertrophy [47–51]. Cahill and Palmer [46], along with McKowen and Voorhies [52], observed that axillary nerve compression within the quadrilateral space commonly occurred with the humerus in a hyperabducted and externally rotated position (such as which occurs during the throwing motion). Although uncommon, this position may also cause arterial compression more proximally where the axillary artery travels beneath a hypertrophied pectoralis minor muscle, potentially resulting in thrombosis and distal embolization [53–56].

Quadrilateral space syndrome typically presents as a vague posterior or lateral pain over the dominant shoulder of young, athletic individuals. Patients may also complain of night pain and mild weakness, especially with forward elevation and/or abduction. The presence of paresthesias over the lateral deltoid is not uncommon and strongly indicates axillary nerve involvement. Aside from these typical complaints, other historical findings are largely nonspecific and generally do not contribute to the diagnosis.

Although physical examination findings are nonspecific in many cases, it is most important to rule out other, more common causes of shoulder pain such as rotator cuff tears and labral lesions, especially in overhead throwing athletes. Tenderness to palpation directly over the quadrilateral space may occur with concomitant weakness and/or atrophy of the posterior deltoid. This finding should alert the clinician to the potential for neurovascular compromise within the quadrilateral space.

Provocative maneuvers for the diagnosis of quadrilateral space syndrome are rarely reported; however, there are a few techniques that can be used to piece together the diagnosis. Although not always present, the deltoid lag sign may indicate posterior deltoid weakness (see Chap. 3), and the Hornblower’s sign (see Chap. 4) may indicate concomitant weakness of the teres minor muscle (both the deltoid and the teres minor muscles are innervated by the axillary nerve). In addition, abnormal sensation may be noted over the lateral deltoid since the sensory branch of the axillary nerve provides innervation to the skin overlying this area. Some authors suggest that forward flexion, abduction, and external rotation of the humerus can reproduce symptoms when the position is held for approximately 2 min; however, this method has not been evaluated in the literature [48]. Because of vague presenting signs and symptoms, a high index of suspicion is needed to correctly diagnose quadrilateral space syndrome by physical examination. Subclavian arteriography demonstrating stenosis or blockage of the posterior circumflex humeral artery with the arm abducted and externally rotated is thought to confirm the suspected diagnosis even though most patients do not have vascular symptoms [46].

Several types of brachial neuritis exist and differ in clinical presentation depending on the most likely cause. These include idiopathic, hypertrophic, hereditary, and traumatic types.

Idiopathic brachial neuritis is most commonly asymmetric (bilateral in 1/3 of cases [58]) and affects men more than women at a rate of at least 2:1 [49]. The condition typically has a bimodal age distribution, occurring most commonly in patients in their 20s and 60s [58]. Approximately half of patients report preceding events such as flu-like symptoms [59], recent vaccination [61, 62], and/or recent surgery [63] in the days just prior to the onset of symptoms, leading some to believe the condition may be immune-modulated [58]. Pierre et al. [64] demonstrated oligoclonal banding consisting of elevated IgG titers against herpes simplex and varicella zoster viruses in the cerebrospinal fluid of patients with brachial neuritis. Biopsies of the brachial plexus have also revealed mononuclear infiltrates, further suggesting an immunological basis for the disease [65, 66]. In addition, treatment with immune-modulating drugs such as corticosteroids and IVIg has been helpful on occasion [67–71].

Hypertrophic brachial neuritis has an unknown cause; however, its features differ from that of the above condition in that evidence of demyelination is evident on histologic examination, similar to other demyelinating diseases such as Gullain–Barre syndrome [72, 73]. Signs of generalized polyneuropathy, however, are absent. In addition, brachial plexus edema manifests as an enlarged appearance on MRI that suggests the diagnosis of hypertrophic brachial neuritis (Fig. 10.21) [58, 74].