Many of the same painful conditions that affect the lumbar spine may also affect the cervical spine, and the symptoms and treatments may be similar (e.g., Stauffer, 1991). However, the symptoms of cervical spinal disorders tend to be more widespread and vague, relative to those of lumbar spinal disorders (that tend to be more localized and discrete). Also, as a consequence, the physical findings of cervical disorders are more difficult to isolate and to precisely document the actual anatomic location based on objective physical examination (Kang, Sowa, & Woods, 2012). As noted by Wiesel et al. (2010), cervical pain resulting from structural pathology is more persistent and may require more intensive intervention. For example, cervical radiculopathy (i.e., related to the nerve root) results from the compression or irritation of a cervical spine nerve root and usually produces symptoms of pain and paresthesia (i.e., an abnormal sensation, such as burning, prickling) along the nerve root distribution. In 25 % of these patients, persistent and/or recurrent neck pain occurs, and surgery may be needed. Cervical myelopathy (i.e., functional disturbance of the cervical spine) results from compression of the entire spinal cord, rather than from an isolated nerve root, and is a much more serious condition. Symptoms include numbness and impaired fine motor function of the fingers and hands, as well as weakness in the lower extremities, gout, and balance difficulties, and often urinary systems dysfunction. If there are no signs of nerve root compression or other neurological symptoms, then there is no firm evidence that surgery is beneficial for cervical pain (Carragee et al., 2009).

Often, symptoms of neck pain, shoulder pain and headache can co-occur, so that it may be difficult to isolate the specific anatomic, nerve root and sensory areas that are involved. Thus, there is a wide array of symptoms that can be reported, including pain, tenderness, stiffness, muscle spasms, and headache. With the above caveats in minds, it has been estimated that 1.6 % of all occupational musculoskeletal injuries are in the cervical region (Bureau of Labor Statistics, 2007). It should also be noted that, with the growth in occupations that involve more repetitive movement types of work (such as keyboard operations, small assembly lines), there has been an increase in cervical, as well as upper extremity, injuries that result in workers’ compensation claims. Table 1.2 presents a summary of many specific diagnoses related to cervical spine injuries.

Finally, one specific type of cervical/neck disorder that is receiving increased attention today is whiplash and neck pain-related disability (Schofferman & Koestler, 2005). Although many such injuries are caused by motor vehicle accidents, other occupationally related causes may produce it, such as falls and head-related collisions/accidents. Such injuries are of great concern because approximately 4–8 % of neck whiplash patients become partially or totally disabled over time (Schofferman & Koestler, 2005). Thus, they need to be appropriately treated at the acute stage before they become more chronic and disabling.

As can be seen in Table 1.3, there are a great number of upper-extremity injury diagnoses, ranging downwards from the shoulder, elbow, wrist, and hand. As a result, there are physicians who specialize in only specific injury area. Many of these injuries are caused by repetitive work or recreational activities (such as continuous neck, arm and/or hand movements that can negatively affect the muscles/nerves of these areas). Again, as we discussed earlier for the other musculoskeletal injuries, there is still some lack of consensus as to what precise criteria to use in diagnosing many upper-extremity injuries. On a global level, the general approach to diagnosis involves the following: a clinician’s physical examination of the injured area; the assessment of the range of motion, strength, and palpation of muscle tendons/ligaments of the area; and the evaluation of self-reported pain while performing these evaluations. Quite often, imaging tests may be ordered if the patient experienced a blunt trauma, or if there are other signs of serious pathophysiology.

Two well-known upper-extremity disorders are rotator cuff injury and carpal tunnel syndrome. In terms of the former, the rotator cuff is a set of four muscles that are responsible for the rotation and elevation of the shoulder while providing stability to the humerus (i.e., the bone that extends from the shoulder to the elbow). Damage to the rotator cuff may be the result of a traumatic injury, or due to a more cumulative trauma due to repetitive overuse. One or more of the four tendons connecting the rotator cuff muscles to the bone may be torn, and patients will report pain over the anterior lateral shoulder. This pain may awaken the patient from sleep and may be exacerbated by overhead activities. Complete tears of the tendons may require surgery, especially if patients start to develop atrophy and weakness of the shoulder muscles. It has been reported that patients who were receiving workers’ compensation, and those with prior surgical procedures, are more likely to need revision surgery (Piasecki et al., 2010). Also, they are less likely to return to work or display improvement in self-reported pain, disability, and strength (Holtby & Razmjou, 2010).

The most frequent cause of occupational wrist pain (with carpal tunnel syndrome being the most commonly diagnosed disorder) is cumulative trauma or overuse. Carpal tunnel syndrome occurs when the transverse carpal ligament compresses the median nerve as it passes though the wrist, resulting in symptoms such as decreased sensation and paresthesia (i.e., an abnormal sensation, such as burning and prickling, to the three radial fingers). As symptoms progress, atrophy to the thenar muscles of the thumb may develop (Wiesel et al., 2010). It should be noted that the incidence of the diagnosis and resultant surgery for this syndrome has been significantly increasing during the past decade, both in the United States and other industrialized countries (Atroshi, Englund, Turkiewicz, Tägil, & Petersson, 2011).

Table 1.4 presents various lower-extremity disorders. Again, as can be seen, there are a great number of them, ranging downwards from the hip to the feet. Of these, knee disorders are extremely prevalent in adults, accounting for approximately three million healthcare visits per year. In fact, knee trauma is the second most common occupational injury (second only to low back strain). Acute knee injuries include damage to the ligaments (especially the anterior collateral ligament) or damage to the cartilage (especially the meniscus). As noted by Wiesel et al. (2010), the rates of knee surgeries have dramatically increased over the past few decades, particularly in younger patients. They now make up a patient population who undergo some of the most frequently performed orthopedic procedures.

Similar to the upper-extremity disorders, because there are so many types of lower-extremity disorders, there are different physicians who specialize in assessing and treating specific injury sites. Likewise, the general approach to diagnosis is similar to that discussed for upper-extremity injuries. As noted by Hernandez and Peterson (2013), various disorders of the knee (such as meniscal tears in lesions, bursitis, and osteoarthritis) and the ankle (e.g., osteoarthritis) are most common for workers in occupations that have high physical demands on the lower limbs, such as construction workers and carpet and floor layers.

Over the past two decades, there has been a plethora of research studies attempting to isolate specific risk factors that may be associated with the development and maintenance of various types of musculoskeletal pain and disability disorders. Hernandez and Peterson (2013) characterized such risk factors into three broad categories: (1) biomechanical risk factors (such as ergonomic variables in the workplace that increase repetitive body part movements or that increase repetitive body part movements or that demand improper and/or static postures/positions), (2) psychosocial risk factors (such as high work demands, low job control, lack of workplace/supervision support), and (3) individual risk factors (such as gender, age, sedentary lifestyle, personality characteristics). Indeed, the face validity of these three categories can be readily seen from earlier models/causal theories presented in the scientific literature, as will be delineated below. Likewise, Wright and Gatchel (2002) outlined a general list of various risk factors, as presented in Table 1.5.

Punnet and Wegman (2004) have also highlighted such risk factors, in stating that musculoskeletal disorders:

… occur in certain industries and occupations with rates up to three or four times higher than the overall frequency. High-risk sectors include nursing facilities; air transportation; mining; food processing; leather tanning; and heavy and light manufacturing (vehicles, furniture, appliances, electrical and electronic products, textiles, apparel and shoes)… Upper extremity musculoskeletal disorders are also highly prevalent in manual-intensive occupations, such as clerical work, postal service, cleaning, industrial inspection and packaging… Back and lower limb disorders occur disproportionately among truck drivers, warehouse workers, airplane baggage handlers, construction traders, nurses, nursing aides and other patient-care workers, and operators of cranes and other large vehicles…. (p. 14)

Howard (2010) has provided a comprehensive review of the various models to be presented next. For example, in an early conceptual model of neck and upper-extremity musculoskeletal disorders, proposed by Armstrong et al. (1993), a number of individual characteristics (e.g., personality/coping skills, health status, work experience) were identified as important variables that directly moderated the effects of the work environment on stress and strain reactions. Subsequently, Sauter and Swanson (1996) extended this model into a broader ecological model of causation of upper-extremity injuries. They not only incorporated physiological and psychosocial variables but also included cognitive component factors (such as fear of losing one’s job, poor performance, not meeting personal goals, as well as frustration with control and confidence issues) that could mediate the effects of work demands and workplace psychosocial stress on muscle tension and poor posture. An additional feature of their ecological model was the presence of a “positive feedback mechanism.” That is to say, if an injury occurred, then the psychosocial impact of that injury would further exacerbate the symptoms, thereby leading to additional increased disability.

Feuerstein (1996) also proposed a work-style model in conceptualizing occupational upper-extremity disorders. There are three work-style factors in this model: physiological changes, behavioral changes, and cognitive changes. If these factors are occupationally altered by psychosocial stress, high-demand tasks, and/or ergonomic factors, then the probability of developing an upper-extremity musculoskeletal injury will be increased. In essence, this model again emphasizes the importance of the interaction between psychosocial and physical stressors (and their feedback) on the development/exacerbation of upper-extremity injuries.