The complexity of the shoulder becomes much more manageable when we divide it into four subgroups

When checking the shoulder clinically, chiropractors often overlook many areas. As a chiropractor first and kinesiologist second, I do not like to miss anything, and therefore try to be very thorough in my clinical assessment. That being said, I think everyone can agree that the shoulder presents many challenges to the doctor, and can also cause many varied symptoms to the patient.

The typical statement, “my shoulder hurts” has many different implications. My favorite patient is one that comes in saying, “The orthopedic doctor said it was my rotator cuff.” I have found that this generalization by many doctors and the lack of attention to detail tends to group many shoulder ailments into common categories, such as “rotator cuff injury,” “shoulder impingement,” or “dislocated shoulder,” to name a few.

I encourage you to take a step back and look at the shoulder more as a holistic practitioner would look at the shoulder. Consider that the body is a closed kinematic chain and that “everything affects everything.” With that in mind, we have our basic tools to address any shoulder problem that may present in our office. That being said, I hope this article will give you more insight into an area that I think is greatly misinterpreted and misunderstood. Let’s keep it simple. The complexity of the shoulder becomes much more manageable when we divide it into four subgroups:

1. the sternoclavicular joint (SC);
2. the acromioclavicular joint (AC);
3. the glenohumeral joint (GH), and
4. the scapulothoracic articulation (ST).

The Sternoclavicular Joint
At the SC articulation, there is a fibrocartilagenous disc that is attached superior to the clavicle and inferiorly to the manubrium sterni. The disc aids in absorbing shock that is transmitted from the arm and shoulder to the torso. The joint is supported by ligaments as well as the subclavius muscle. The costoclavicular ligament holds the inner end of the clavicle down. The interclavicular ligament aids the costoclavicular ligament in providing structural strength. Minor support is given by the anterior and posterior SC ligaments. The SC joint is the only bone-to-bone contact in the shoulder.

Costoclavicular Syndrome is a common ailment that refers to entrapments of the brachial plexus, the subclavian artery, and/or the subclavian vein as they travel beneath the clavicle and over the first rib. Symptoms of entrapment are usually transient and brought on by motions of the clavicle or the first rib. Muscle testing will reveal weakness patterns when the clavicle or first rib is stressed.

To check, flex the patient’s arm to 140° and test arm or hand muscles. This motion rotates the clavicle involving the subclavius muscle. The shoulder can also be rotated posteriorly with the arm extended to 30°. Finally, ask the patient to inspire (this raises the scalene muscles and elevates the first rib); if the clavicle has been displaced inferiorly, or the first rib is superior, the arm will be weak.

The Acromioclavicular Joint
The AC joint allows gliding between the clavicle and the scapula. The basic strength of the joint is derived from the ligaments that support the area. The ligament between the clavicle and the coracoid process prevent the superior displacement of the clavicle, while the AC ligament prevents separation of the clavicle and the acromion. The muscular support for the joint is basically supplied by the deltoid and the upper trapezius. Weakness in the muscles will affect the length of the ligaments. Over time, degenerative changes, including wear of the ligaments, rotator cuff thinning, and osteophytic changes, will probably be found.

Acromioclavicular Strain/Sprain: According to David Leaf, chairman of the USA chapter of the International College of Applied Kinesiology, “this injury is one of the most frequently overlooked injuries in the body. Many people who are driving and involved in an accident have this injury due to the stress that is applied to the joint on impact. Any person who has fallen and caught himself with his arm, or anyone complaining of aches or pains in the upper trapezius, would be considered a candidate for this injury.” The patient will usually present with trigger points in the upper trapezius, as well as a decreased cervical rotation and lateral flexion. You may also find posterior deltoid weakness, but the weakness may also extend to the muscles of the rotator cuff. Weakness in the hand may also be found due to a thoracic outlet syndrome created by the overcontraction of the shoulder muscles as they compensate for the injury of the ligaments at the AC joint.

When the AC joint is involved, there will usually be instability of the clavicle or the scapula. According to Leaf, this causes what is referred to as “reversed glenohumeral rhythm.” This is the elevation of the shoulder along with the humerus. Normally, the shoulder should stay in a horizontal position while the humerus is abducted. The trigger points in the upper trapezius will be dramatically reduced when the AC joint is approximated. There may also be trigger points in the posterior deltoid and the infraspinatus muscles. All muscles of the rotator cuff should be examined and tested. The most common weak muscles are the posterior and middle deltoid, as well as the supra- and infraspinatus.

To check the SC and the AC joints and to ensure proper clavicle positioning, I would perform a muscle test to determine the line of correction. If you do not practice kinesiology, then you can do the various muscle tests associated with the joints. For example, for the clavicle you could do the pectoralis sternal muscle test:

The arm is flexed to 90 degrees with the elbow extended. The arm is then internally rotated so that the palm is facing away from the body. The stabilization hand is placed over the opposite ASIS. Contact is made on the lower arm superior to the wrist. Pressure is directed laterally and slightly superiorly. If straight lateral is considered to be 90°, the test angle would be at 130°. A weak muscle would indicate clavicular involvement.

Once the clavicle is corrected, I would then check all of the ribs. In particular, I would check the first rib, which lies directly under the clavicle. This is typically one of those overlooked areas, and it is extremely important. If this rib is out of the joint capsule, it can contribute to much shoulder discomfort and pain, not to mention a great deal of muscular weakness and multiple trigger points. The best way that I have found to adjust this rib is with an activator. The contact is achieved with the patient lying supine. Move to the head of the patient and place the activator below the medial clavicle, pointing inferiorly. The line of correction is superior to inferior with a slight lateral-to medial angle. It is usually very tender upon palpation, and the patient will notice immediate results after the correction.

The Glenohumeral Joint
This is a multiaxial ball-and-socket joint. Basically, the structures allow three types of motion to occur: rolling, gliding, and rotating. The glenoid joint serves as a base for stabilization, as the humeral head is so much larger than the glenoid surface. The ligaments only help to prevent anterior displacement of the humerus. The major support of the shoulder comes from the rotator cuff. The rotator cuff is formed by the teres minor, infraspinatus, supraspinatus, and subscapularis. Anterior support is provided by the subscapularis tendon. While individually these muscles act as rotators of the humerus, together they act to hold the humerus in the glenoid cavity. As a result, the soft tissues surrounding the joint are major contributors to its stability. Anterior instability of the shoulder is the most common type of instability.

Glenohumeral Mobilization: This is restricted motion of the arm with pain over the lateral aspect. Check the glenohumeral joint capsule for fixations. The technique for correction would involve placing a rolled towel in the axilla, and stabilizing the glenoid cavity while applying pressure against the lower aspect of the humerus toward the torso. This pressure will pull the head of the humerus away from the glenoid cavity.

Restricted flexion and/or internal rotation, with pain over the anterior capsule: While applying posterior pressure over the head of the humerus, stabilize the lower humerus with your other hand.

Restricted abduction as well as internal and external rotation: Place one hand in the axilla to stabilize the shoulder. Your other hand would grasp the humerus and apply steady pressure in an inferior direction.

Restricted elevation and/or internal/external rotation: Place one hand near the head of the humerus in the axilla and the other over the elbow. Pressure is then applied to pull the head of the humerus out of the glenoid cavity while applying pressure over the elbow toward the body. Another technique that you could use would be to stabilize the scapula (patient lying prone) with one hand, and with the other, grasp the humerus and apply traction in an inferior direction.

Restricted extension and/or external rotation, with pain over the anterior capsule: With the patient lying prone, stabilize over the lower humerus, and with the other hand apply pressure in an anterior direction over the head of the humerus. You may also want to place a block over the anterior chest to stabilize the clavicle.

The Scapulothoracic Articulation
The scapula provides a broad base for muscular attachment. It “glides” across the muscles of the thorax. The scapula may be fixed on the thorax or the arm fixed on the scapula with motion controlled by the muscles attaching the arm to the scapula or the muscles connecting the scapula to the thorax. The scapula serves as a pedestal on which the humerus is elevated. In normal abduction of the arm, most of the initial elevation occurs at the glenohumeral joint. Since the static and dynamic stabilization begins with the ST relationship, we need to check for anteriority, inferiority, laterality, and medial fixations on both scapulas.

Scapular mobilization: To aid in freeing restricted motion of the scapula, apply pressure in a superior and lateral direction. This is followed by applying pressure in exactly the opposite direction. Using this procedure, the scapula is freed slowly in a superior/inferior gliding action. Also, grasp the scapula with both hands by placing the tips of the fingers under the spinal border of the scapula. Pressure is applied to elevate and protrude the scapula. Follow this with pressure gliding the scapula toward the spine. Finally, grasp the spine of the scapula with one hand and then the other. Pressure is applied as to rotate the inferior angle in a lateral direction while pressure is also applied medially on the superior spine of the scapula. Alternate the direction of force slowly, increasing the gliding of the scapula on the ribs below.

Cervical discs: Another common area of involvement that I would like to call a “clinical pearl” are cervical discs. The cervical spine is not as prone to disc herniation as the lumber spine; however, the cervical spine does present with a special type of lesion, coined “hidden cervical disc” by George Goodheart, DC, developer of applied kinesiology. This problem creates a special type of symptom pattern.

In the cervical spine, the sensory and the motor roots do not merge until after the intervertebral foramina. This causes patients to present with more varied symptom patterns than in the lumbar spine. With the cervical disc, the vertebra slides up the line of the facets. This causes an anterior, superior misalignment of the vertebra and results in a bulging of the disc.

Anterior cervical discs, in my opinion, are one of the most overlooked areas of the spine. I believe that checking for them should be part of every protocol. By applying caudal pressure on top of the head, a strong muscle will weaken if there is a hidden cervical disc. By therapy localizing, you could then determine the exact spinal level of involvement. Correction is made by manual adjustment or with an activator placed directly over the disc and an A-P line of drive. Make sure the activator is on a low-force setting, as these can be painful.

Once the anterior discs and the subluxations of the neck are corrected (especially the atlas), I will also check the occiput and the temporomandibular joint TMJ. The TMJ is integrally related to the shoulder, and I have found it to be an essential component of healing. Often, I find that the condyles tend to move anterior, while the jaw tends to go posterior.

Once these are corrected, I then check for posterior rib heads, followed by the rest of the spine. I would then finish up the structural corrections by looking to the extremities. Many times, I find radius and ulna, as well as carpals and metacarpals. Last but not least, don’t forget the legs and feet, as they are very important to overall structural balance.

You do not need to become overwhelmed by the complexity of the shoulder and its many areas. If we keep it simple and break it down into the four subgroups, it will be much easier to assess the underlying complaint. Once you have an effective system for checking the shoulder, it really is not hard at all to diagnose and treat. In fact, it really is simple.

Carl Amodio, BA, DC, is in practice at Whole Body Health Inc in Roswell, GA. Contact him at drcarlamodio@comcast.net.