Editor’s note: This article is drawn from Erik Dalton’s extensive body of work and was written before his January 11, 2025, passing. His contributions to the field of manual therapy have left an enduring legacy. Though Erik is no longer with us, we continue to share his inspirational wisdom.
One of your regular clients, with no previous shoulder issues, reports mild shoulder discomfort and morning shoulder stiffness, causing a sensation of weakness when they move their arm overhead or reach for an object. You assure your client that you’ll pay extra attention to their shoulders. Which of these joints are you most likely to focus on?
A) The glenohumeral (GH) joint
B) The acromioclavicular (AC) joint
C) The scapulothoracic (ST) articulation
D) The sternoclavicular (SC) joint
Most therapists head straight for the GH joint because this highly mobile and inherently unstable joint is susceptible to a variety of injuries. However, therapists who work with athletes might be biased toward the AC joint because it is especially prone to overuse sports injuries. Maybe you’re aware of scapular dyskinesis and are concerned about abnormal movement patterns of the scapula during shoulder motion; in this case, your focus is the ST joint. If you answered D, the SC joint, you’re in the minority; the SC joint is the structure many therapists overlook when clients report shoulder issues.
The GH, AC, ST, and SC joints are so closely interconnected that discussing them in isolation is almost impossible. They form part of the complex and highly mobile shoulder girdle, which works as a unit during upper-limb movements. However, in this article, our focus is on the overlooked SC joint. We’ll briefly review its structure and function before we assess and address SC joint restrictions with techniques that easily integrate into most massages. We’ll learn to factor this joint into our session plans whenever clients report general shoulder issues.
Anatomy
You’ll remember that the SC joint is the articulation between the clavicle and the manubrium of the sternum (Image 1). It is a complex synovial saddle joint with a fibrocartilaginous disc and a surrounding joint capsule. The disc divides the joint into two compartments and acts as a shock absorber by dispersing forces that pass through the clavicle and sternum. The anterior sternoclavicular, posterior sternoclavicular, interclavicular, and costoclavicular ligaments stabilize the SC joint, as does the first rib, which lies beneath the SC joint and attaches to the manubrium.
Movement
The SC joint has the distinction of linking the upper limb to the axial skeleton. It plays a critical role in shoulder movement and stability, allowing the clavicle to elevate, depress, protract, retract, and rotate anteriorly and posteriorly along its axis. The clavicle also makes small gliding movements on the manubrium.
Because the clavicle and scapula are attached at the acromioclavicular joint, the motions of the clavicle at the SC joint follow those of the scapula. The clavicle acts as a strut to hold the scapula in place, so their motions are interdependent. The deltoid, the clavicular head of pectoralis major, the trapezius, sternocleidomastoid (SCM), and subclavius muscles attach to the clavicle. These muscles do not act directly on the SC joint but influence clavicular movements.
Dysfunction
The SC joint is less commonly injured than the GH and AC joints. Still, it can suffer traumatic injuries like ligament sprains, joint dislocation, and clavicle fractures and experience stress from overuse caused by repetitive movements. Scar tissue from previous injuries, osteoarthritis, or rheumatoid arthritis may damage the SC joint or restrict movement, disrupting the mechanics of the shoulder girdle.
Most often, postural deviations like forward-head position, rounded shoulders, and kyphosis cause the sustained protraction of the clavicle. Shallow breathing patterns, emotional tension, and stress can tighten the neck, shoulder, and chest muscles. At the same time, a lack of movement and a sedentary lifestyle can increase SC joint stiffness, muscle weakness, and loss of mobility. Compensation causes some muscles to become chronically hypertonic and others to be weak and inhibited. Pain may cause the nervous system to splint the region with protective muscle spasms.
Assess and Address SC Joint Restrictions
As we discussed previously, the GH, AC, ST, and SC joints are closely interconnected, and shoulder girdle dynamics are complex. Here, we’ll narrow our focus to addressing SC joint restrictions related to clavicular elevation and protraction. These methods ensure we feel confident working with the SC joint as part of our shoulder massages.
Elevation at the SC Joint
When a person shrugs their shoulders, raises their arm to the side (shoulder abduction), raises their arms to the front (shoulder flexion), reaches overhead, or carries a heavy load, the clavicle elevates to accommodate or promote the upward rotation of the scapula and to stabilize the shoulder. At the SC joint, the medial head of the clavicle glides downward on the manubrium to elevate the lateral end of the clavicle. The clavicle must rotate posteriorly around its long axis for smooth movement. In other words, the inferior surface of the clavicle rotates upward so that it faces anteriorly, freeing the lateral end of the clavicle to fully elevate.
Assess SC Elevation Restrictions
To assess the SC joint for elevation restrictions (Image 2), stand on one side of the supine client and place your index and middle fingers on top of the client’s medial clavicular heads (also called the sternal heads). Ask the client to shrug their shoulders and then abduct each arm. Notice if the medial clavicular heads drop downward on the manubrium. If one or both sides don’t drop downward during these movements, a ligament or articular disc restriction is limiting elevation.
Address SC Elevation Restrictions
To address SC joint elevation restrictions (Image 3), stand on the right side of the supine client and bring the client’s arm into 90 degrees of abduction by grasping the client’s forearm with your left hand. Place the soft finger pads of your right hand on the right superior aspect of the medial head of the clavicle. Step forward with your left leg as you press the client’s arm further into abduction. At the same time, gently drag the medial head of the clavicle downward with your right finger pads. Rock back onto your right leg and release the fingers of your right hand. Rock forward, move the client’s arm into abduction, and use your fingers to drag the medial head of the clavicle downward gently. Rock back and forth in this manner several times. Repeat this technique on the other side as appropriate.
Subclavius Release
Hypertonic muscles might also cause elevation restrictions. For example, the subclavius is a small muscle originating on the first rib and attaching to the inferior surface of the clavicle (Image 4).
Its primary function is to stabilize the clavicle by anchoring it to the first rib. It limits excessive clavicle elevation, crucial for controlling and smoothing movements at the SC joint. When the subclavius becomes hypertonic, it restricts the free upward movement of the clavicle, leading to limitations in shoulder elevation, abduction, and flexion. Try this subclavius release technique to address this restriction. Stand on the left side of the supine client and grasp their right wrist with your left hand. Pull the client’s right arm up and across their body to lift the right clavicle off the rib cage. With your right hand, supinate your wrist so your fingers face posteriorly. Use your finger pads to make contact and scrub the subclavius muscle, working proximal to distal along the clavicle. Use a rhythmic counterforce movement by pulling the client’s right wrist toward you as your left fingers scrub the subclavius proximally to distally. Repeat this technique on the other side as appropriate.
Protraction at the SC Joint
When a person reaches their arm forward (shoulder flexion), as in reaching for an object, the scapula protracts, and the clavicle must protract at the SC joint to accommodate this forward motion of the shoulder girdle. Any movement when a person pushes something away from the body (e.g., performing a push-up or bench press) causes the clavicle to protract to increase the range of motion needed for the push. At the SC joint, protraction involves the medial head of the clavicle gliding posteriorly on the sternum while the lateral end moves forward with the scapula.
Assess SC Protraction Restrictions
To assess the SC joint for protraction restrictions (Image 5), stand on the client’s right side and place your left thumb on the anterior surface of the client’s right medial clavicular head. Lift the client’s arm to protract the shoulder; notice here if the medial clavicular head glides posteriorly on the manubrium. If it doesn’t, normal movement at the SC joint is limited. Repeat this process on the left side as appropriate.
Address SC Protraction Restrictions. To address SC protraction restrictions (Image 6), stand at the supine client’s right side with your left hand grasping around the client’s shoulder. Place the thenar eminence of your right hand (avoiding breast tissue) on the anterior surface of the medial head of the clavicle. Lift the client’s shoulder off the table using your left hand while you place gentle downward pressure on the medial head of the clavicle. Using a counterforce rocking movement, lift and lower the client’s arm while you apply and release pressure with your thenar eminence.
Next, lift and hold the client’s arm, maintain downward pressure on the medial head of the clavicle, and ask the client to pull their shoulder down toward the therapy table against your resistance to a count of five and release. Repeat three times and then treat the other side as appropriate.
Remember the SC Joint
In conclusion, while the SC joint may receive less attention than the more commonly addressed GH or AC joints, its role in shoulder girdle mobility and stability is undeniably crucial. Addressing restrictions at the SC joint can often relieve shoulder discomfort and improve range of motion, particularly in cases of clavicular elevation and protraction limitations.
As massage therapists, it’s essential to assess and incorporate SC joint techniques into sessions when clients present with shoulder issues. By doing so, we ensure comprehensive care, addressing all parts of the shoulder complex for better overall outcomes.
