Abstract
The brachioradialis muscle is susceptible to the development of myofascial pain syndrome. This pain is most often the result of repetitive microtrauma to the muscle from such activities as turning a screwdriver, prolonged ironing, repeated flexing of the forearm at the elbow (e.g., when using exercise equipment), handshaking, or digging with a trowel. Tennis injuries caused by an improper one-handed backhand technique have also been implicated as an inciting factor in myofascial pain syndrome, as has blunt trauma to the muscle. The trigger point is the pathologic lesion of brachioradialis syndrome, and it is characterized by a local point of exquisite tenderness in the brachioradialis muscle. This trigger point can best be demonstrated by having the patient simultaneously flex and pronate the forearm against active resistance. Point tenderness over the lateral supracondylar ridge of the humerus may also be present and may be amenable to injection therapy.
Mechanical stimulation of the trigger point by palpation or stretching produces both intense local pain and referred pain. The jump sign is also characteristic of brachioradialis syndrome, as is pain over the brachioradialis muscle that radiates from the lateral epicondyle and superior portion of the muscle into the forearm.
Keywords
brachioradialis syndrome, fibromyalgia, myofascial pain, trigger points, trigger point injection, stretch and spray, antidepressants, pregablin, wrist pain, forearm pain, sports injuries, botulinum toxin
ICD-10 CODE M79.7
The Clinical Syndrome
The brachioradialis muscle flexes the forearm at the elbow, pronates the forearm when supinated, and supinates the forearm when pronated. It originates at the upper lateral supracondylar ridge of the humerus and the lateral intermuscular septum of the humerus. The muscle inserts on the superior aspect of the styloid process of the radius, the lateral side of the distal radius, and the antebrachial fascia. The muscle is innervated by the radial nerve.
The brachioradialis muscle is susceptible to the development of myofascial pain syndrome. This pain is most often the result of repetitive microtrauma to the muscle from such activities as turning a screwdriver, prolonged ironing, repeated flexing of the forearm at the elbow (e.g., when using exercise equipment), handshaking, or digging with a trowel. Tennis injuries caused by an improper one-handed backhand technique have also been implicated as an inciting factor in myofascial pain syndrome, as has blunt trauma to the muscle ( Fig. 44.1 ).
Myofascial pain syndrome is a chronic pain syndrome that affects a focal or regional portion of the body. The sine qua non of myofascial pain syndrome is the finding of myofascial trigger points on physical examination. Although these trigger points are generally localized to the part of the body affected, the pain is often referred to other areas. This referred pain may be misdiagnosed or attributed to other organ systems, thus leading to extensive evaluation and ineffective treatment. Patients with myofascial pain syndrome involving the brachioradialis muscle often have referred pain in the ipsilateral forearm and, on occasion, above the elbow.
The trigger point is the pathognomonic lesion of myofascial pain syndrome and is characterized by a local point of exquisite tenderness in the affected muscle. Mechanical stimulation of the trigger point by palpation or stretching produces not only intense local pain but also referred pain. In addition, involuntary withdrawal of the stimulated muscle, called a jump sign, is often seen and is characteristic of myofascial pain syndrome. Patients with brachioradialis syndrome have a trigger point over the superior belly of the muscle ( Fig. 44.2 ).
Taut bands of muscle fibers are often identified when myofascial trigger points are palpated. Despite this consistent physical finding, the pathophysiology of the myofascial trigger point remains elusive, although trigger points are believed to result from microtrauma to the affected muscle. This trauma may occur from a single injury, repetitive microtrauma, or chronic deconditioning of the agonist and antagonist muscle unit.
In addition to muscle trauma, various other factors seem to predispose patients to develop myofascial pain syndrome. For instance, a weekend athlete who subjects his or her body to unaccustomed physical activity may develop myofascial pain syndrome. Poor posture while sitting at a computer or while watching television has also been implicated as a predisposing factor. Previous injuries may result in abnormal muscle function and lead to the development of myofascial pain syndrome. All these predisposing factors may be intensified if the patient also suffers from poor nutritional status or coexisting psychological or behavioral abnormalities, including chronic stress and depression. The brachioradialis muscle seems to be particularly susceptible to stress-induced myofascial pain syndrome.
Stiffness and fatigue often coexist with pain, and they increase the functional disability associated with this disease and complicate its treatment. Myofascial pain syndrome may occur as a primary disease state or in conjunction with other painful conditions, including radiculopathy and chronic regional pain syndromes. Psychological or behavioral abnormalities, including depression, frequently coexist with the muscle abnormalities, and management of these psychological disorders is an integral part of any successful treatment plan.
Keywords
brachioradialis syndrome, fibromyalgia, myofascial pain, trigger points, trigger point injection, stretch and spray, antidepressants, pregablin, wrist pain, forearm pain, sports injuries, botulinum toxin
ICD-10 CODE M79.7
The Clinical Syndrome
The brachioradialis muscle flexes the forearm at the elbow, pronates the forearm when supinated, and supinates the forearm when pronated. It originates at the upper lateral supracondylar ridge of the humerus and the lateral intermuscular septum of the humerus. The muscle inserts on the superior aspect of the styloid process of the radius, the lateral side of the distal radius, and the antebrachial fascia. The muscle is innervated by the radial nerve.
The brachioradialis muscle is susceptible to the development of myofascial pain syndrome. This pain is most often the result of repetitive microtrauma to the muscle from such activities as turning a screwdriver, prolonged ironing, repeated flexing of the forearm at the elbow (e.g., when using exercise equipment), handshaking, or digging with a trowel. Tennis injuries caused by an improper one-handed backhand technique have also been implicated as an inciting factor in myofascial pain syndrome, as has blunt trauma to the muscle ( Fig. 44.1 ).
