Definition

Trapezius strain is often considered a part of the myofascial pain syndrome (MPS). This is a common diagnosis of patients who present to outpatient clinics for musculoskeletal pain disorders [1]. There is no standard definition of trapezius strain or MPS; however, MPS is described as a disorder characterized by acute and chronic nonspecific pain that affects a small number of muscles and involves single or multiple trigger points that are usually located in tight bands within the affected muscles [2]. The pain in this area must not be mistaken for cervical radicular pain that involves the shoulder girdle and the upper limb [3]. The etiology of trigger point formation is not known, but the most accepted hypothesis focuses on the existence of dysfunctional end plates leading to a perpetuated shortening of the muscle [4,5].

Trapezius strain is thought to be due to common repetitive strain or stress injury associated with carrying light loads and certain postures, such as that with working on a computer for long periods [6]. Myofascial trigger points can be the main cause of neck and upper back pain, and the trapezius muscle is the most commonly studied [7]. The condition can also result from acute causes, such as a whiplash injury.

Symptoms

Patients typically complain of a sore or aching sensation in the region of the upper trapezius muscle. Patients may also complain of posterior neck and shoulder pain. Some may have associated posterior headaches, difficulty with sleeping due to shoulder pain, and interscapular area pain. The symptoms can be constant and relieved by rest and worsened with activity. There can be increased pain with cervical movement and hence limitation in neck range of motion. The pain is regional and does not follow spinal segmental or peripheral nerve distribution. Patients may often report that the symptoms are partly relieved with the use of heat or cold modalities and focal pressure.

Physical Examination

The importance of the physical examination is to rule out other conditions that may be causing the patient’s symptoms, such as a radiculopathy, peripheral nerve injury, cervical dystonia, or some other condition that may be suspected on the basis of the history. A neurologic and musculoskeletal examination focusing on the neck and upper body should be done in addition to a general examination. Other evaluations include cranial nerve function, especially checking the spinal accessory nerve; sensation to light touch and pinprick about the face, upper limbs, and torso with attention to dermatomes and cutaneous nerve distribution; muscle stretch reflexes; and strength testing. The findings on neurologic examination are typically normal in primary trapezius strain. The patient may present with a forward head posture, scapular protraction, and compensatory cervical hyperextension. Muscle palpation about the neck and shoulder girdle may reveal tender areas and trigger points, especially in the trapezius muscle. A shoulder examination should be carried out to assess for shoulder disease.

Functional Limitations

Trapezius muscle strain can limit activities requiring the arm to be outstretched in front or to the side. There can be pain with rotation of the head and hence function limitation, such as turning the head for a shoulder check when driving. Pain in certain positions may interfere with restful sleep and thus affect overall function.

Diagnostic Studies