Neck pain is a common clinical problem experienced at some point in life by nearly two-thirds of people. In addition to being a common problem, neck pain is quite disabling, in some countries accounting for nearly as much disability as low back pain. The economic impact of whiplash injuries alone is estimated to be nearly $4 billion.

Neck pain is also quite similar to low back pain in that the etiology is poorly understood and the clinical diagnoses are quite vague. Compared to low back pain, however, which has been the subject of numerous clinical practice guidelines, neck pain has received limited study. The few randomized controlled studies available lack consistency in study design. A review of the National Guidelines Clearinghouse (http://www.ngc.gov) demonstrates eight published guidelines on neck pain, pertaining to the use of facet neurotomy, imaging, and selected rehabilitation and therapeutic interventions in neck pain. This chapter reviews the epidemiology and anatomy of neck pain and provides an evidenced-based assessment of the evaluation, diagnosis, and management of this challenging disorder.

Neck pain is most prevalent in middle-aged adults; however, prevalence tends to vary with different definitions of neck pain and with differing methodologies of neck pain surveys. One study, for example, found that the1-year prevalence in adults ranged from 16.7% to 75.1% and rose with longer time periods. Almost 85% of neck pain may be attributed to chronic stress and strains or acute or repetitive injuries associated with poor posture, anxiety, depression, and occupational or sporting risks. The acceleration and deceleration of a whiplash injury may result in cervical sprains or strains, which, in turn, are common causes of neck pain. Radicular neck pain occurs later in life, with an estimated incidence of 10% among 25- to 29-year-olds, rising to 25%-40% in those older than 45 years.

Occupational neck pain is ubiquitous and not limited to any particular work setting. Predictors for occupational neck pain include little influence on the work situation, work-related psychosocial factors, and perceived general tension. Predictors of occupational neck pain include prolonged sitting at work (>95% of the workday), especially with the neck forward flexed 20 degrees or more for more than 70% of the work time.

The cervical spine is a highly mobile column that supports the 6- to 8-lb (2.7-3.6 kg) head and provides protection for the cervical spinal cord. The cervical spine consists of 7 vertebrae, 5 intervertebral discs, 14 facet joints (zygapophyseal joints or Z-joints), 12 joints of Luschka (uncovertebral joints), and 14 paired anterior, lateral, and posterior muscles. The vertebrae can be grouped into three major groups: the atlas (C1), the axis (C2), and the others (C3-C7). The atlas is a ring-shaped vertebra with two lateral masses, each with superior and inferior facets to articulate with the occiput and C2 respectively, as well as an anterior portion of the ring to articulate with the odontoid process (dens) of C2. The axis consists of a large vertebral body (the largest in the cervical spine) with the anterior odontoid process articulating with C1 and inferior and superior facet joints. This odontoid process has a precarious blood supply, placing it at risk for nonunion and malunion when fractured. The atlantooccipital articulation accounts for 50% of the flexion and extension range of motion (ROM) of the neck and the alantoaxial joint accounts for 50% of the rotational ROM of the neck.

Each of the remaining cervical vertebrae consists of an anterior body with a posterior projecting ring of the transverse and spinous processes that form the vertebral foramen for the spinal cord. The most prominent spinous processes that can be palpated are C2 and C7 (vertebral prominens). The spinous and transverse processes are the origin and insertion of the multiple interspinous and intervertebral ligaments and muscles. Between each vertebral body are intervertebral discs, each consisting of a gelatinous center (nucleus pulposus) with a tougher, multilayered (onion skin–like) surrounding annulus fibrosis. Each vertebral body from C3 to C7 articulates with the others through a bony lip (uncus) off the lateral margins called the joints of Luschka. These are not considered true diarthrodial joints (because they have no synovium); however, they may develop degenerative spurs, limiting motion. The facet joints are part of the transverse process and are paired superiorly and inferiorly. The facet joints have articular cartilage and a synovium that can be involved in degenerative and inflammatory processes. Among the multiple interspinous and intervertebral ligaments, the most important are the anterior and posterior longitudinal ligaments along the vertebral bodies, the ligamentum nuchae along the spinous process, and the ligamentum flavum along the anterior surfaces of the laminae. The weaker posterior longitudinal ligaments help stabilize the intervertebral discs posteriorly and are often damaged in disc herniation. Hypertrophy of the ligamentum flavum may contribute to spinal stenosis or nerve root impingement. Eight cervical nerve roots exit posterolaterally through the neuroforamina. Given that there are seven vertebrae, each cervical root emerges through a neuroforamen above the vertebra of its number (ie, the C6 root arises between C5 and C6), with C8 exiting between C7 and T1. The cervical cord gives rise to the nerves that innervate the neck, upper extremity, and diaphragm. In the evaluation of problems related to the cervical spine, the physician should have a basic understanding of the motor and sensory innervations of the upper extremity (Table 25-1).

The musculature of the cervical spine includes flexors, extensors, lateral flexors, and rotators. Major flexors include the sternocleidomastoid, scalenes, and prevertebrals. Extensors include the posterior paravertebral muscles (splenius, semispinalis, capitis) and trapezius. Lateral flexors include the sternocleidomastoid, scalenes, and interspinous (between the transverse processes) muscles, and the rotators include the sternocleidomastoid and the interspinous muscles. The ability of the cervical spine to absorb and diffuse the energy from acute injuries is related to its lordotic curvature and the energy absorption of the paraspinal muscles and intervertebral discs. The paraspinal muscles can be strained and become spastic. Occasionally, so-called trigger points—hyperirritable myo-nodules and taut muscle fiber bands—may develop.

The combined motion of all the preceding joints gives a significant ROM of the neck, allowing the head to scan the environment with the eyes and ears. Normal ROM includes extension of 70 degrees (chin straight up to the ceiling), flexion of 60 degrees (chin on chest, or within 3 cm of chest), lateral flexion of approximately 45 degrees (ear to shoulder), and rotation of approximately 80 degrees (looking right and left). The center of motion for flexion is C5-C6 and for extension, C6-C7; hence, degeneration and injury often occurs at these levels. ROM can be reduced by injury to muscles, vertebrae, or discs, or by degenerative processes causing spondylosis and spinal stenosis.

Prevention strategies for high-risk groups have been employed for both neck and lower back pain. A review of 27 investigations into educational efforts, exercises, ergonomics, and risk factor modification found sufficient evidence for only strengthening exercises as an effective prevention strategy. A more recent randomized controlled trial showed that specific resistance and all-round exercise programs were more effective than general health counseling in preventing occupation-related neck pain.

Symptoms and Signs

The mechanism of injury of the cervical spine, like that of other injuries can be classified in multiple ways: acute injuries—including a fall, blow to the head, or the whiplash injury—or chronic-repetitive injury—associated with recreational or occupational activities. Other classifications can include the direction of the stress or force generating the injury: flexion, extension-hyperextension, axial load, lateral flexion, or rotation. At 30 degrees of forward flexion, the cervical spine is straight and most vulnerable to axial load-type injuries. Most chronic neck pain is associated with poor posture and ergonomics, anxiety or depression, neck strain, or occupational and sport-related injuries.

In the evaluation of cervical spine problems the most important first step is to obtain a thorough history, ascertaining the mechanism of injury. In many cases, the mechanism of injury may identify the injury or guide the physical examination. The examiner should identify any history of prior injuries or problems with the cervical spine (eg, a history of prior surgery or degenerative arthritis). Radicular or radiating symptoms in the upper extremity should be identified. This includes radiating pain, motor weakness, numbness, or paresthesias of the upper or lower extremities. Determining both the apparent origin and source of radiating symptoms is important. Occasionally, a myofascial trigger point may exhibit referral pain patterns that may mimic those of radiculopathy, and may often play a role in chronic neck pain. Conversely, musculoskeletal neck pain can also refer to the head and play a large role in cervicogenic headaches. Additionally, the examiner should ask about any symptoms related to upper motor neuron pathology. This includes bowel or bladder dysfunction or gait disturbance.

Additional information gathered should include the duration and course of symptoms, aggravating and alleviating motions or activities, and attempted prior treatments initiated by patients on their own or by other providers. Comorbid diseases such as inflammatory spondyloarthropathies, cardiac disease, or gastrointestinal problems should be identified, as well as a history of tobacco or alcohol abuse. Current occupational and recreational activities and requirements should be identified, as they may contribute to the underlying problem and identify the desired end point for recovery and return to activity.

Cervical Spine Examination

The cervical spine is examined in an organized and systematic way that includes adequate exposure of the neck, upper back, and shoulders for observation; palpation of bony and soft tissues; evaluation of ROM; a Spurling test for nerve root irritation; assessment of Lhermitte sign for cervical radiculopathy; upper extremity motor and sensory examination; and evaluation for upper motor neuron symptoms.

Observation

Observation should begin as the patient walks into the examination room, looking for the presence or absence of normal fluid motion of the neck and arm swing with walking. After exposure, the examiner may note the posture (many patients have a poor head-forward with rounded-shoulder posture that contributes to chronic cervical muscular strain), shoulder position (looking for elevation from muscle spasm), and evidence of atrophy. The examiner should also observe for head tilt or rotation.

Palpation

Palpation of major bony prominences and the soft tissues should be performed. The spinous processes and the facet joints (about 1 cm lateral and deep to the spinous process) should be gently palpated, noting tenderness. (Caveat: If enough pressure is applied to the spinous process, pain can be produced in virtually any patient.) Palpation of the prevertebral and paravertebral muscles should be performed, noting hypertonicity, pain, or the presence of tender or trigger points. Common sites for trigger points include the levator scapulae (off the superior, medial margin of the scapula), upper trapezius, rhomboids, and upper paraspinals near the insertion into the occiput. Palpation of trigger points may elicit tenderness, referred pain (which may mimic radicular symptoms), or a local twitch response.

Range of Motion