Massage and Bodywork Magazine for the Visually Impaired - Emily's Nerve Traction Injury

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September/October 2014 Issue

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Emily's Nerve Traction Injury

By Whitney Lowe
[Clinical Apps]

Injuries are sometimes fairly straightforward. Examples of a straightforward injury might be a medial collateral ligament injury in sports or carpal tunnel syndrome from repetitive overuse. However, many times injuries require more detailed biomechanical analysis to determine what actually occurred and whether massage would be helpful. In this installment of Clinical Apps, we take a look at a unique injury condition affecting the shoulder and upper extremity.

The Case
Emily has a large dog, Boomer. Several weeks ago, while walking her dog, Emily had stopped to talk to a neighbor when Boomer abruptly lunged after a squirrel. The leash was firmly wrapped around her right hand, and because she was caught completely off guard, she was pulled off her feet and hit the ground pretty hard. She doesn’t remember exactly how she landed, but remembers Boomer was on her right, so her right arm was stretched out to that side.
Emily also reports that she was looking to the left when Boomer lunged after the squirrel. She remembers feeling a sharp pain on the right side of her neck and pain shooting down her right arm immediately after the accident. The pain was worse the next day. It has been two weeks since the initial injury and Emily now wants to see if treatment can help her resolve the lingering issues.

Anatomical Considerations
Emily continues to have significant shoulder pain and also reports a sharp, shooting pain down her right arm. There is no visible sign of injury in Emily’s neck, shoulder, or upper extremity regions. Consequently, it will be very important to get more detailed information from her about the initial injury to determine what tissues were likely injured.
There are several high-intensity forces that could be directly related to Emily’s present complaints of shoulder and arm pain. The foremost is the sudden pulling or traction injury on the shoulder. It’s quite likely that some of the rotator cuff muscles were injured in this incident because of their key role in stabilizing the humeral head.
As evidenced in the name, the rotator cuff muscles’ primary role is shoulder rotation, and they are also involved in supraspinatus abduction. The attachment sites of the four muscles form a cuff around the top of the humeral head. By enclosing the entire humeral head, these short muscles pull it closer into the glenoid fossa. The shoulder joint lacks bony stability, so the rotator cuff muscles are key to providing that stability.
In Emily’s injury scenario, a sudden traction force was applied to the upper extremity, placing an enormous pulling load on the rotator cuff muscles. Compounding the problem is the fact that Emily was in a relaxed state at the time, and thus the muscles were not taut or prepared for the pulling force, which means their ability to withstand the traction load was greatly reduced.
Emily also likely sustained compression trauma in the shoulder joint when she fell. If she landed on her elbow or outstretched hand, it is likely she jammed the humeral head into the glenoid fossa as she landed on the ground. The sudden compressive load on the shoulder joint could have thrust the humeral head against the underside of the acromion process and seriously pinched subacromial tissues, such as the supraspinatus tendon, subacromial bursa, or upper margins of the glenohumeral joint capsule. We should also consider that this potential sudden compressive load could have jammed the humeral head against the glenoid labrum. A sudden compressive injury, like falling on an outstretched arm, is a common mechanism for producing injury to the glenoid labrum.
There is a good possibility that the pain Emily is feeling down her upper extremity is coming from rotator cuff damage. However, she reports the pain as more like a sharp and burning sensation, which usually points to some type of neurological injury. Most nerve injuries in the upper extremity, such as thoracic outlet syndrome and carpal tunnel syndrome, involve nerve compression. But the mechanics of this particular injury situation don’t indicate the likelihood of nerve compression. She could have developed an acute nerve compression by slamming her hand on the ground when she fell. However, she is also reporting sensations in her neck and upper extremity, and this is unlikely to result from nerve compression at the wrist.
When we consider the biomechanics of her injury more closely, another possibility emerges. Emily reported that she was in a relaxed state and looking in the opposite direction of the dog when he lunged at the squirrel. The dog took off to her right and suddenly jerked the leash, which would have pulled her upper torso to the right, making her head rapidly flex to the left laterally. This sudden and rapid movement to her right is similar to what happens in lateral whiplash in an automobile accident when a person is hit from the left.
The rapid left lateral flexion of her head in combination with the immediate forceful pulling of her right arm away from her body could easily have produced what is called a nerve traction injury. This is an injury in which a nerve is exposed to excessive tensile (pulling) force, as opposed to the compressive forces that are the cause of most nerve injuries. Nerve traction injuries produce identical symptoms to those of a nerve compression problem. However, there are several important considerations that affect treatment solutions for these types of injuries.

Assessment and Evaluation
As mentioned earlier, there was no visible sign of trauma in Emily’s shoulder region, so functional evaluation will be important for determining the tissues most likely injured. She reported the greatest amount of shoulder pain just underneath the acromion process, but reports that it also extends somewhat around the back side of her shoulder. Our focus in physical examination will be on tissues in those regions.
During movement, Emily’s greatest shoulder pain is with abduction movements, especially when she performs these actions against any type of resistance, such as trying to pick something up and lift it to her side. The pain she feels deep in her shoulder tends to worsen the farther she moves her arm into abduction. She feels this pain both actively and passively in abduction, but it is significantly worse in active abduction. She also reports that the pain is most pronounced when resisted abduction is performed. There is also some pain with active and passive forward flexion, although it is not as strong as the abduction.
The fact that Emily feels more pain with resisted abduction than with active or passive abduction suggests a muscle tendon unit is most likely the problem, not a deep shoulder structure like the glenoid labrum. When we consider the initial injury, we can infer the supraspinatus would have been under exaggerated tensile load as her arm was pulled away from her body. This sudden traction force could likely have caused a strain to the supraspinatus muscle tendon unit. It is quite likely that Emily also sustained a minor strain to the posterior rotator cuff muscles (infraspinatus and teres minor) from the sudden traction force.
We are also able to reproduce some of Emily’s posterior shoulder pain by palpating structures around the posterior humeral head. Similar pain is also reproduced at the far end of active and passive medial rotation tests and somewhat with resisted lateral rotation. Her posterior shoulder pain is not as strong as what she feels just beneath the acromion process. Pain located in the posterior shoulder region could make us suspect the posterior rotator cuff muscles (infraspinatus and teres minor). If these muscles were involved, pain would likely increase at the end of medial rotation as those tissues are stretched, and during resisted lateral rotation when they are contracted, as they are in Emily’s case.
We now have a good idea of the tissues involved in Emily’s shoulder pain, but what about the pain she is experiencing in her neck and down the upper extremity? She reports this pain is aggravated when she laterally flexes her head to the left, either actively or passively. The pain is also reproduced if she adopts the injury position, in which her head is laterally flexed to the left and her right arm is abducted and straight out to the right side. In this position, the nerves of the brachial plexus in the neck region are significantly stretched.
Emily’s shooting pain sensations extend all the way down into her hand and into the palm and first and second fingers. The cutaneous innervation map for the hand indicates that this region is innervated by the median nerve. The median nerve is in its most lengthened position when the arm is outstretched, similar to what happened when Boomer lunged ahead. It would then seem likely, based on Emily’s symptoms and the motions that further aggravate her pain, that a median nerve traction injury may have occurred.

Treatment Strategies
Now that we have a good idea about the nature of Emily’s injury, it’s time to consider the most effective treatment options. Starting with the more prominent superior shoulder pain, it appears she sustained a strain to the supraspinatus. The most prominent area of tissue damage is the distal musculotendinous junction. The problem with attempting to treat this particular area with massage is that it is mostly inaccessible due to the tissue being underneath the acromion process.
The most effective way to access the distal musculotendinous junction is to have the client’s arm pulled as close in to her side as possible. In this position, deep friction can be applied just inferior to the acromion process. This friction technique will help manage scar tissue and encourage fibroblast proliferation to provide the optimal healing environment for the torn muscle and tendon fibers.
A similar treatment strategy can be used for the posterior rotator cuff tendons, which sustained a similar injury. These tendons are far more accessible on the posterior aspect of the shoulder. Friction techniques can be applied directly to the site of greatest tissue tenderness (usually the musculotendinous junction) to help encourage tissue repair and optimum return to function.
Later in Emily’s rehabilitation process, we can encourage greater tissue function through active engagement methods. For the posterior rotator cuff group, deep stripping techniques are applied to the infraspinatus and teres minor as she moves her shoulder into medial rotation. Performing longitudinal stripping techniques on these muscles as they elongate helps encourage tissue alignment and restore optimal function. Similar treatment can be used with the supraspinatus muscle by performing stripping techniques as the shoulder is moved into adduction.
The traction injury Emily sustained to her brachial plexus and median nerve in her upper extremity is going to be more difficult to address. When a nerve has been overstretched, there is nothing that soft-tissue manipulation can do to the nerve to correct the stress. It is simply a matter of allowing time for the damaged nerve tissue to heal appropriately. However, massage can play a role in making sure the surrounding region and tissues do not further aggravate the nerve traction injury.
In Emily’s case, massage is applied to the lateral cervical region and throughout the length of the upper extremity to help reduce any further aggravation on the upper extremity nerves or brachial plexus by surrounding muscles, which may become hypertonic and may be compressing or irritating the nerves.

Conclusion
Emily’s case demonstrates that accurate biomechanical analysis of the forces affecting a tissue injury can be crucial for determining the nature of the injury. Treatment strategies should be specific for each individual. Emily’s treatment strategy was determined by in-depth mechanical analysis of the forces impacting her at the time of the injury. This analysis educates your client with valuable information about the injury, and directs the course of your treatment.

Whitney Lowe is the author of Orthopedic Assessment in Massage Therapy (Daviau-Scott, 2006) and Orthopedic Massage: Theory and Technique (Mosby, 2009). He teaches advanced clinical massage in seminars, online courses, books, and DVDs. You can find more ideas in Lowe’s free enewsletter—and his books, course offerings, and DVDs—at www.omeri.com. 

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