Dorsal Scapular Nerve Syndrome Treatment and Causes
Weakness and fatigue of the rhomboid and levator scapulae muscles can produce mild winging of the scapula and a lack of shoulder stabilization. These muscles are innervated by the dorsal scapular nerve, which travels from the lower cervical spine down the posterior thoracic region where nerve branches control the rhomboid and levator muscles. Nerve compression or entrapment can produce a dull, aching pain along the medial border of the scapula which can radiate down the lateral surface of the arm and forearm.
Many patients describe a slowly increasing dull ache and fatigue in their mid back over months. The back pain usually increases at the end of the work day or after exercise. Work postures that involve leaning forward and working with the hands in front of the body increase the dull pain, especially sitting and typing with poor posture. Over weeks and months the discomfort increases and patient eventually experiences pain radiating down the arm and forearm.
Most people are unaware of the lack of shoulder stabilization that has increased strain on the rotator cuff muscles and tendons during this time. Nor do they realize their shoulder is functioning less optimally during exercise, especially lifting dumbbells or throwing activities. They may notice a soreness developing in their rotator cuff, bicep tendon, or shoulder external rotators and assume the pain is an aggravation of a previous shoulder injury. Some may notice changes in shoulder abduction, extension, or reaching above their heads. Because dorsal scapular nerve entrapment leads to dysfunction in scapular stabilization, the first recognized symptom is tendinopathy in shoulder muscles or upper thoracic spine joint pain.
When patients feel pain radiating from their back down their arm, they often think of thoracic disc lesions, nerve root compressions (pinched nerves), thoracic outlet syndrome, and nerve traction injuries. Throwing athletes may notice the early shoulder fatigue and assume the repetitive microtrauma has lead to shoulder glenoid articular damage, arthritis, cartilage damage, costoclavicular syndrome, suprascapular nerve syndrome, axillary nerve damage, or spinal accessory nerve damage. Without direct injury or trauma, many of these injuries or conditions could produce shoulder and radiating pain. The location and pattern of pain cannot lead to a definitive diagnoses, so proper evaluation and a thorough functional examination reveal the signs of dorsal scapular nerve syndrome.
Causes and Symptoms of Dorsal Scapular Nerve Entrapment
The dorsal scapular nerve receives branches from C4 – T1 nerve roots. Seventy-six percent of the dorsal scapular nerve originates from the C5 ventral ramus, which travels behind a major portion of the brachial plexus where it pierces the medial scalene muscles. This is a common site of the nerve entrapment or compression. As it passes through the medial scalenes it continues traveling between the posterior scalene and levator scapulae muscles before reaching the superior angle of the clavicle.
From the superior angle of the clavicle it runs with an artery along the medial margin of the scapula and underneath the rhomboid muscles. Along this path the nerve supplies small branches to the levator scapulae, rhomboid major, and rhomboid minor muscles. These muscles are heavily involved in scapular stabilization. By inserting on the superior angle, the levator scapula elevates and rotates the scapula. Whereas the rhomboid muscles pull the scapula medially as well as elevate it.
Compression of the nerve anywhere along its path produces symptoms in the muscles downstream from the compression. Clinically, dorsal scapular nerve injuries and compression produce a mild form of scapular wing in a resting position. The medial and inferior scapular borders are lifted off the chest wall. Patients affected by the nerve compression find it difficult to bring their scapula together. Reaching above one’s head further raises the medial border and interferes with the angle of the scapula off the chest wall. Advanced testing, such as electromyographic analysis, will demonstrate injury to the rhomboid and levator muscles. An EMG/nerve conduction velocity study is diagnostic. This form of scapular winging is different than winging from serratus anterior injuries.
Additionally, in a study titled “Entrapment Neuropathies: differential diagnosis and management,” Fisher and Gorelick thought the nerve compression might be an unsuspected component of many cases of shoulder pain. Clinically this seems very likely because of the importance these muscles play in shoulder stabilization. If the scapula cannot be held firmly in a fixed position, the muscles that are contracting off of it cannot properly control the shoulder or glenohumeral joint motion. The excessive motion and movement of the scapula shifts the glenohumeral joint angle and produces more stress and strain on all of the shoulder muscles, including the deltoid, teres minor, teres major, infraspinatus, supraspinatus, subscapularis, bicep, or coracobrachialis muscles. A small and subtle shift in glenohumeral angles can produce significant strain and damage to these muscles and tendons, producing shoulder pain, tendinopathy, sprains, strains, or possibly tendon rupture.
Treatment for Dorsal Scapular Nerve Syndrome
Additional advanced imaging may be ordered by your primary care physician or orthopedic surgeon to further evaluate the condition. An MRI provides information on the soft tissue of the cervical spine, discs, and neck muscles. Surgical intervention may be utilized in some cases. However, this nerve entrapment responds very well to conservative treatment that restores normal scapular motion and movement, in addition to relieving the nerve compression. Pain management physicians may be utilized in severe cases for pain relief and management. Pain medication, anti-inflammatory medication, or muscle relaxers may be prescribed by your healthcare provider to enhance conservative treatment.
Conservative treatment goals are to decrease muscle spasms, increase muscle control, and provide back and shoulder pain relief. Proper evaluation and diagnosis should reveal the site of nerve entrapment. Alternative and conservative treatments address the offending muscles or soft tissue adhesions that are compressing the nerve and producing nerve damage.
Your chiropractic physician or sports medicine specialist will provide several types of treatments to decrease muscle spasms and increase muscle flexibility of the scalene, levator, rhomboid, and shoulder muscles. Active rehabilitation procedures will improve spinal joint dysfunction and decrease muscle and neuromuscular dysfunction. Cervical and thoracic joint pain may be contributing to the development of the neck and back pain. Activities that overwork and cause injury to the scalene muscles often produce strain on the facet joints and produce mild joint pain symptoms. As the joints lose normal ranges of motion and movements, they begin sending pain signals to the brain which produces mild chronic pain symptoms and further increases scalene, trapezius, and levator muscle spasms. Continued muscle spasms alter neck and back posture, leading to more strain and spasm of the scalene and neck muscles. This cycle of pain, spasm, posture changes, and dysfunction slowly progresses over months leading to the syndrome’s development.
Sports therapy or muscle therapy techniques for soft tissue injuries include Graston Technique, massage therapy, Active Release Technique (ART), manual therapy, passive stretching and active exercise. Proprioception, muscle pattern exercises, and dynamic exercises may be added over time with progress. Many patients are surprised at their level of neck muscle spasm and how tender the scalene muscles are during the muscle therapy. These sports medicine soft tissue techniques quickly decrease muscle soreness and pain by enhancing muscle flexibility.
Often these muscles have been in prolonged spasm for months and years with overuse. Muscles and tendons develop scar tissue or fascial adhesions between the fibers, which further prevents their normal sliding motions and contractile movements. These fascial adhesions may directly compress the dorsal scapular nerve or limit the medial scalene muscle flexibility so severely that the lack of muscle flexibility tightens around the nerve as it travels through the medial scalene muscle. Often soft tissue adhesions produce mild amounts of inflammation and irritation around the muscles, tendons, and ligaments. By breaking up the scar tissue and muscle adhesions, the nerve is able to slide through the medial scalene muscle without compression or entrapment.
Active Rehabilitation and Therapy
Once the offending component of the dorsal scapular nerve compression is removed, treatment focuses on increasing muscle strength, endurance, and stabilization of this scapula. Stability exercises are given to reteach the scapular muscles how to work together. Often the nerve compression produces compensation mechanisms in the body where certain muscles begin to spasm and overcompensate for the lack of rhomboid and levator muscle contraction. Therapy and treatment addresses the overcompensation mechanisms and restores proper neuromuscular control of the scapular and shoulder muscles. Oftentimes palpation or compression of the site of nerve entrapment increases radiating pain in the upper arm and forearm. After several treatments with massage therapy, Graston technique, or Active Release Technique, the symptoms improve.
Conservative treatments to decrease inflammation and provide relief include electric therapy, ultrasound, heat, ice, cold laser, rest, and analgesic treatments. Your chiropractor or physical therapist may combine several or all of these passive treatments into your treatment plan. Some equipment may provide better pain relief than others, depending on the site of compression and level of damage.
During active rehabilitation in the office, many patients feel increased stiffness and soreness in their neck, upper back, and shoulder. Rehab procedures and protocols are given for making the rhomboid and levator muscles contract to properly stabilize the scapula. These exercises fatigue and create new muscle soreness for several weeks during the initial phases of active rehabilitation. With progress, the muscle soreness decreases and shoulder function improves.
Your healthcare professional will educate you on on the expected timeline for recovery in addition to limitations on activity. Many people can continue with their normal home, work, and recreational activities with minimal limitations. Some restrictions may be placed upon certain lifts or intense lifting. Continuing to challenge and overwork the shoulder predisposes other shoulder muscles and tendons to injury, and care should be avoided to prevent a compensation injury to any of the other muscles, tendons, ligaments, or joint capsule.
Dorsal scapular nerve syndrome may play a role in many shoulder injuries and is often misdiagnosed or underdiagnosed in clinical settings. Often healthcare providers and patients focus on what tissue hurts, instead of what is predisposing that tissue to become injured. A lack of scapular stabilization often creates many shoulder sprains and strains. Treatment should always focus on what hurts and restoring it to previous shoulder motions and functional levels, however attention should also be paid to the entire system to prevent shoulder dysfunction and pain.
When one component of the shoulder is not working correctly, compensation mechanisms often work for months or years to make up for the lack of functional activity and stabilization. Eventually the compensation mechanisms become overwhelmed and shoulder sprains and strains develop. Often patients with chronic shoulder pain and arm injuries have dysfunction in the upper extremity stabilization. A trained sports injury professional will examine the entire system and provide appropriate treatment to correct the injured area, in addition to the dysfunctional system that led to shoulder pain and weakness.