Maven Sports Medicine effectively combines our high standard of orthopedic rehabilitation practice with our clear understanding of elite fitness and sports performance. Maven’s Doctors of Physical Therapy have decades of combined practice experience in orthopedic rehabilitation, sports strength/conditioning, fitness, and athletic training. Our dedication to providing excellent evidence-based care to all our active and athletic patients remains consistent.

Anatomy:

Joints

Relying primarily on dynamic stability derived from its surrounding muscles, the shoulder is comprised of several articulations (joints)- the glenohumeral (G-H), acromioclavicular (A-C), sternoclavicular (S-C), coracoclavicular (C-C), coraco-acromial (C-A), and the scapulothoracic (S-T) joints.

The glenohumeral joint, we’ll refer to as the "primary" shoulder joint. The head of the humerus (the bone of the upper arm) attaches to the glenoid, which is a relatively concaved region located on the lateral region of the scapula (the shoulder blade). The labrum is a fibrocartilaginous ring that helps to deepen the "socket" of the glenoid to increase the surface contact of the humerus to the glenoid.

By nature, the shoulder is one of the most mobile joints, and therefore, least stable joints of the body. Multi-axial in nature, the shoulder sacrifices joint stability for joint mobility. In fact, many would liken the "fit" (congruency) of the shoulder joint to a golf ball (head of the humerus) on a golf-tee (glenoid), unlike the hip joint, which is a true "ball-and-socket" joint. Having such mobility is not necessarily a bad quality for certain populations- for example, professional pitchers, swimmers, and other overhead athletes must have excessive mobility, i.e., even more joint laxity (looseness) than the average person has, in order to perform the amazing feats that they do from season to season.

Given the greater laxity and poor congruency of the shoulder joint, as compared to other joints, it is no wonder that the shoulder needs to be well supported by dynamically by muscles.


Muscles

Any discussion of the shoulder muscles must include the rotator cuff, which is discussed in more detail further down. The muscles that attach to the shoulder complex include the following: trapezii (upper, middle, lower), rhomboids (major/minor), levator scapulae, deltoids (anterior, medial, and posterior heads), serratus anterior, biceps brachii (long head), coracobrachialis, pectoralis major/minor, latissimus dorsi. As you can see, there are many dynamic elements (muscles/tendons) to consider when referring to the muscles of the shoulder. Several of these can have a profound effect, positively or negatively, on joint mobility and as a result, on general everyday upper extremity function.


Rotator Cuff

The overall purpose of the rotator cuff is to protect the shoulder joint. The four muscles that comprise the rotator cuff- supraspinatus, infraspinatus, teres minor, and subscapularis, work together to provide a compressive-depressive force on the G-H joint while you perform overhead (external rotation, abduction) activities, in particular. This active joint compression-depression is crucial in minimizing the approximation between the head of the humerus and the A-C joint, while performing such activities; when the rotator cuff is compromised, this approximation may increase leading to a greater chance of shoulder impingement, rotator cuff tears, and dislocations.

While they do have a collective function, each rotator cuff muscle has a separate function as well. The teres minor and infraspinatus are the key muscles for external rotation; these muscles enable you to reach above and behind your head and for overhead athletes, cock the arm back.

The supraspinatus is perhaps the most frequently torn tendon of the rotator cuff due to its proximity to and position under the acromion relative to the other tendons. It is involved primarily in the initial 30 degrees of abduction. The main function of the subscapularis is to internally rotate the humerus. It is probably the least common RTC muscle to be torn or injured.

Pectoralis Major and Latissimus Dorsi: Due to their distal origin from the trunk and relative large surface area, the pectorals and latissimi are able to generate a substantial amount of force for overhead activities, in particular. Since both the "pecs" and "lats" are powerful internal rotators of the humerus, however, they can contribute to a forward or rounded shoulder position, thereby leading to shoulder pathology. Many people who participate in resistance training often have an imbalance in their training approach, focusing on these "show-off" muscles, but neglecting the midback muscles, which help to retract the shoulders. Stretching these muscles and supplementing a midback strengthening program can help balance the shoulder forces.

Deltoids: The deltoids are the shoulder "positioners". They have a relatively short arc of motion and assist the shoulder in abducting, extending, and flexing the shoulder.

Trapezii:

• Upper trapezius: This muscle (along with the sternocleidomastoids) often gives the thickened neck appearance seen on many wrestlers and football players. The upper trapezius elevates the scapula
• Middle Trapezius: The middle trapezius plays an important role in scapular stabilization activities, i.e., activities that help to maintain an optimal position of the scapula during shoulder movement.
• Lower Trapezius: Also plays an important role in scapular stabilization.

Bones of the Shoulder

There are only three bones of the shoulder- humerus (long bone of the upper arm), clavicle (collarbone), and scapula (shoulder blade). The only bone that connects the shoulder joint to the axial skeleton is the clavicle (collarbone). What this means is that if the clavicle were to be removed from one’s body, the shoulder would be completely detached from the body. This is not to be confused with shoulder separation. The scapula (shoulder blade) meets the clavicle via the acromion process, which is an extension of the scapular spine, to form the A-C joint. As mentioned before, the head of the humerus is the end of the long bone of the upper arm. The head of the humerus articulates with the glenoid of the scapula and is located directly under the A-C joint.


Capsule

Every "true" joint has a joint capsule, which essentially, is connective tissue that surrounds the ends of two bones (this is why the S-T joint is not a true joint) and contains synovial fluid inside the region.


Bursa

fluid-filled sac that is usually located near the tendinous insertion of a muscle onto the bone. In the case of a painful shoulder, there are two that may be implicated- the subacromial bursa and the subdeltoid bursa (READ MORE BELOW)

-Vascular supply- the shoulder receives its blood supply from several arteries including the anterior and posterior circumflex arteries, the axillary artery (supreme thoracic artery), thoracoacromial artery (pectoral, acromial, deltoid, clavicular branches), lateral thoracic, arcuate artery (long head of the biceps brachii), subscapular (thoracodorsal and circumflex scapular branches) and the suprascapular artery. Although studies on the glenohumeral capsule have demonstrated the region to be well-vascularized, some authors describe a "critical zone" or hypovascular zone in the region of the supraspinatus tendon insertion denoting decreased blood flow/supply into this region; incidentally, this rotator cuff tendon is often the most injured of the four tendons.

-Innervation: the fifth and sixth cervical nerve roots provide the shoulder with most of its nerve supply. To some degree, C3, C4 and even the spinal accessory nerve (CN XI) provide some innervations to surrounding muscles of the shoulder.


Differential Diagnoses

As with other joints, it is not always the case that pain in the shoulder region is derived from the joint itself. Shoulder pain may stay local to the site of injury/pathology or may radiate distally down the lateral aspect of the arm, sometimes down to the elbow and forearm. Patients with shoulder pain often describe a dull, achy, sharp, or shooting pain that occurs with movement, depending on the chronicity of the pain and extent of injury. However, a person can experience what is known as, referred pain, i.e., pain or symptoms that are caused by pathology located in a different region or system of the body. Consider the following differential diagnoses (diagnoses that should be ruled out in order to say, with reasonable certainty, that the pain/problem that the patient has is derived from the region at hand):

Cervical (neck) spine: irritated or inflamed nerve roots of the cervical spine (may or may not be disc-related) may refer pain down the lateral aspect of the upper extremity in a similar pain pattern as the shoulder. Patients often describe a shooting, burning, or numbness/tingling sensation that is often worsened by movements of the neck. The cervical spine should always be screened as a source of radiating pain during the history and examination, especially when the cause or description of pain is not typical for the shoulder.

Brachial plexus/adverse neural tension: Believe it or not, a vast network, or plexus, of nerves resides in your armpit, of all places, (also known as the axilla) and is well protected by surrounding muscles. Injury in this network, however, can cause a pain pattern similar to shoulder pathology.

Trigger point: an area of localized tenderness in a given muscle or tendon that can refer pain to neighboring regions that are distal to the localized tenderness

Neural tension: upper limb neural tension is essentially tightness of the nerve sheaths that house the peripheral nerves leading into the extremities.

Systemic: Organs may refer pain to different regions of the body. For example, patients who are experiencing a myocardial infarction (heart attack) often complain of radiating pain down the left upper extremity. Similarly, some types of GI pain can refer to the shoulder as well. This is why rehabilitation specialists spend a particular amount of time discussing the past medical history with patients, referring them to the necessary specialists when a red flag or suspicious sign/symptom occurs.

Non-organic: unfortunately, some types of pain are not necessarily physiologically-based. Symptom magnification, e.g., may be the result of a person attaching an emotional or psychological need to the pain at hand. Patients who malinger are often after some sort of gain or compensation, as are those involved with some sort of litigation.

General Treatment Approaches for the Shoulder:

At Maven, we believe that in many cases, shoulder pain can be effectively addressed with a combination of the following:

• Manual therapy (joint mobilization, soft tissue mobilization)
• Activity (proprioceptive neuromuscular facilitation, functional strengthening, and scapular stabilization exercises)
• Education (posture re-education, ergonomic and activity modification, home maintenance activities)

Passive modalities including ultrasound, electrical stimulation, cold laser, heat, and cryotherapy strategies are also employed on an as-needed basis, but certainly are not the mainstay of our approach.