KEY WORDS

Work-related musculoskeletal disorders (WRMSDs), or musculoskeletal disorders (MSDs). Refers to injuries of muscles, tendons, and joints that result from work activities.

Biomechanical Factors. Body movements, postures, or activities that contribute to injury risk.

Ergonomics. The science of designing a work environment to fit the individual employee.

Engineering Controls. One of three ergonomic principles for reducing or eliminating work-related injury.

Definition

Work-related musculoskeletal disorders (WRMSDs), or musculoskeletal disorders (MSDs), are defined as injuries that are caused by or aggravated by workplace activities. They account for up to 60% of all workplace illnesses, and survey data have shown that more than 80% of sonographers have some form of MSD that can be attributed to their work activities.

Causes and Risk Factors

The causes of MSD can be attributed to three groups of factors:

Biomechanical factors—awkward scanning postures, excessive force used in performing an exam, workspace design

Faulty work organization—infrequent breaks, overtime and on-call incentives, poor employee training

Injury management—delayed injury reporting and diagnosis, improper injury management, returning worker to injury-producing environment

Work activities that contribute to injuries in sonographers are repetitive motions, forceful exertions or strain, awkward or unnatural positions, uncomfortable positioning of the limbs, static postures, overuse, and frequent reaching above shoulder level.

There are a number of individual factors that also increase one’s risk for MSD, including sonographer height and weight, age, gender, systemic illnesses, level of physical fitness, and hand dominance. Shorter workers are forced to reach to access their patients, and taller workers may have to use awkward postures to scan their patients or to view the ultrasound monitor. Muscle strength usually peaks between 25 and 35 years of age, which is why older workers are at higher risk for injury. Male workers generally have more muscle mass and muscle strength than female workers. Systemic illnesses that may compromise blood flow to muscles and tendons increase one’s risk for musculoskeletal injury.

In addition, there are certain leisure activities that can aggravate injury, such as playing musical instruments, running, sewing, and racket sports. These activities put extra strain on the muscles of the hands and forearm and the intervertebral discs of the back.

The current use of filmless storage in sonography has contributed to the increase in MSDs because this now allows sonographers to move rapidly from patient to patient without sufficient rest periods. The use of narrow transducers for certain examinations requires a tighter, or “pinch,” grip that causes excess stress on the fingers and forearm muscles. Chairs or stools and examination tables that are not adjustable result in excessive reaching and twisting to reach to the patient during an examination. Increases in workloads are due to downsizing and shortages of skilled sonographers. Thus, each sonographer is performing more patient examinations during the workday, often necessitating more overtime and fewer work breaks.

Symptoms

Symptoms of musculoskeletal injury are as follows:

Pain

Inflammation

Swelling

Loss of sensation

Numbness

Tingling

Burning

Clumsiness

Muscle spasm

Symptoms of MSD can occur after months or years of overuse and have been staged according to their reversibility and outcome.

Stage 1—aching and fatigue that subside with overnight rest and do not result in a reduction in work performance.

Stage 2—recurrent aching and fatigue that do not subside with overnight rest; symptoms occur earlier in the workday and affect performance at work.

Stage 3—aching, fatigue, and weakness result in reduced performance in work and leisure activities; pain occurs with nonrepetitive movements; symptoms disturb sleep and may last years.

Types of Musculoskeletal Disorders

Specific disorders of MSD are as follows:

Tenosynovitis/tendonitis—inflammation of the tendon sheath and tendon

Carpal tunnel syndrome—entrapment of the median nerve due to inflammation and edema of the soft tissues in the carpal tunnel of the wrist

Cubital tunnel syndrome—entrapment of the ulnar nerve due to inflammation of the soft tissues in the elbow

Trigger finger—inflammation of the tendon sheath of a finger, entrapping the tendon within and preventing flexion and/or extension of the finger

de Quervain’s disease—tendonitis specific to the thumb

Lateral/medial epicondylitis—inflammation of the epicondyles of the distal humerus caused by repeated twisting of the forearm and exerting pressure with the arm