Written by Dawn Lewis
I want to discuss several ways that the brachial plexus can be impinged. Brachial plexus impingement causes tingling and numbness down the arm and into the hand. Although, sometimes the symptoms are only felt in the hand.
First, and most obvious, the brachial plexus can become impinged at the cervical vertebrae. The five roots for the nerves in the brachial plexus exit the spinal cord between C5 and T1. Problems at this area of the cervical spine can create an impingement on the nerve roots. These problems might include: misalignment of the vertebrae, tension and compression of the vertebrae, bone spurs, and/or disc degeneration.
Some of these issues, like bone spurs or disc degeneration, cannot be fixed through bodywork. However, bodywork can temporarily ease the symptoms. Misalignments of the vertebrae and/or compression of the vertebrae can easily be treated with bodywork. By releasing the ligaments in the facet joints between the vertebrae and the intervertebral joints between the vertebral bodies and the discs, we can quickly ease up tension and facilitate re-alignment of the vertebrae.
Additionally, being able to release the ligaments of the first rib and mobilize the first rib, which attaches to both C7 and T1, will allow a more neutral position in those 2 vertebrae. Finally, knowing which muscles are effecting the vertebrae and effectively releasing those muscles completes this work. Muscles that will need to be released are all scalene muscles, longus capitis, longus colli, and the cervical and thoracic erector muscles.
The second area where the brachial plexus can become impinged is at the thoracic outlet. The thoracic outlet is a small space between the first rib and the clavicle. If either of these bones is misaligned, the space is diminished and pressure can be put on the brachial plexus.
To work with this area, we need to understand the construction of the sternoclavicular joint. The SC joint is an articulation between 3 bones, the sternum (specifically the manubrium), the clavicle (specifically the medial head), and the first rib (specifically the anterior rib head). Within the SC joint is an articular disc that divides the joint in half. This gives this joint the ability to move in all directions, and, although it will not more much in any direction, if the joint becomes stuck in any one position, it has the potential to misalignment both the clavicle and the first rib.
To effectively open up the space between the clavicle and the first rib, and thereby release pressure on the brachial plexus, we will first need to release the ligaments in the SC joint and let the joint float back into alignment. Next, we must look at the mobility of the first rib, and if it is immobile, we need to mobilize it. Finally, we need to release the large muscles that attach to both of these bones, namely scalenes, trapezius, pectoralis major, anterior deltoid, and SCM.
Third on our list of areas where the brachial plexus can become impinged is the axilla. After passing through the thoracic outlet, the brachial plexus travels into the axilla and down the medial side of the upper arm. The nerves begin to divide and innervate different tissues as they go.
Muscles in the axilla include latissimus dorsi, teres major, serratus anterior, subscapularis, and coracobrachialis. Along with these muscles, the axilla houses many lymph nodes, the axillary vein and artery, and, of course, the brachial plexus. Additionally, there is a complicated bony box that creates the axilla. On the lateral side of the axilla is the medial humerus, on the medial side is the ribcage, posterior is the lateral scapula, and superior is the glenohumeral joint. The pectoralis muscles create an anterior border for the axilla.
I have had therapists tell me that we should not work in the axilla because it has so many structures. I disagree. I think this is the exact reason we must work in the axilla. The environment of the axilla, a small space with many structures, lends itself to adhesions. As the structures begin to stick together, they create tension and shortening, which leads to impingements on all the structures in the axilla, including the brachial plexus.
To effectively release the axilla we must address many of the structures within the axilla. So, we must release the muscles, release the ligaments so bony alignment is restored, and work with the tension in the connective tissue, which is abundant in the axilla.
Our final cause of brachial plexus impingement is what I call the perfect storm. Tension and fairly intense pain to the medial side of the scapula, between the scapula and the spine, that is putting the arm to sleep. What generally happens in this scenario is that the upper ribcage, specifically ribs 3 through 7 move posterior and become immobile.
As the ribs move posterior, they push the scapula into abduction, as well as creating almost no space between the scapula and the ribcage. As the scapula moves into abduction, the glenohumeral joint moves anterior and lateral. This movement shifts the acromioclavicular (AC) joint anterior. If the AC joint shifts anterior, the clavicle has obviously moved anterior as well. This creates a misalignment of the SC joint and movement of the first rib.
Along with all this bony movement, this pattern creates tension in serratus anterior and pectoralis minor. Both muscles are in close proximity to the brachial plexus as it comes from the thoracic outlet and into the axilla. The tension in the muscles and the shift of the bones diminish the axillary space.
Further, the movement of ribs 3 through 7 tightens iliocostalis cervicis, which has the potential to misalign C4 through C6. And the movement of the 1st rib creates tension in the scalenes and has the potential to misalign all the cervical vertebrae.
So, this person’s brachial plexus is now likely being impinged at the cervical spine, at the thoracic outlet, and in the axilla. Ouch! And, of course, this is the hardest issue to correct. You will have to look at all the areas involved, but nothing will move or release until you can mobilize ribs 3 through 7.