The shoulder is a complex articulation. Over time, it has developed into a highly mobile connection between the axial skeleton and the upper limb. It is a joint that requires exceptional amounts of motion. This motion comes at a cost though; that cost is stability. What it gains in mobility it sacrifices in stability. This contributes to some of the issues we encounter with respect to shoulder injuries.
As always, knowledge of the basic anatomy, which extends beyond the glenohumeral joint, is critical in understanding the shoulder complex.
Brachial plexus- Stinger, burner
Thoracic Outlet Syndrome (TOS)
AC Joint Compression
The shoulder complex is comprised of the gelnohumeral, acromioclavicular, sternoclavicular and, unofficially, the scapulothoracic joint. All of those joints must work in harmony to produce fluid, pain-free motion at the upper limb. This is especially true in overhead sports or movements. Dysfunction in one joint will impact all of the others 'upstream and downstream' from it. Stiffness or laxity creates issues and compensations that must be addressed mechanically or neurologically.
First let us look at the clavicle. The clavicle functions, along with the scapula, as a 'strut' between the ball and socket of the scapula and humerus, and the axial skeleton, namely the sternum anteriorly and the ribs posteriorly. It is an S-curved structure, which permits attachment anchors for a number of muscles, including such things as the pectoralis major inferiorly and sternocleidomastoid superiorly. The clavicle functions as a bumper anteriorly which protects the neurovascular bundle, including the brachial plexus and the subclavian vessels. It is a commonly injured structure because of its' articulations at the AC and SC joints and, a common and painful fracture site.
Next we'll look at the humerus. It forms the ball in the glenohumeral articulation and is considered the true shoulder 'joint'. Due to its' shape and the fact that it's head is a rounded structure on a flat surface, the glenoid fossa of the scapula, the glenohumeral joint permits a wide variety of motions including straight plane, multiplanar and rotational motions. The humerus is the origin and also the insertion for a number of important muscles in the shoulder including many one and two joint muscles.
The scapula is an interesting bone that is relatively flat in shape with a few unique projections including the coracoid and acromion processes. Anteriorly the coracoid, latin for crow's beak, is the origin of a number of muscular and ligamentous structures in the shoulder. It is the origin for muscles such as pectoralis minor, the short head of the biceps and coracobrachialis. The coracoid also provides stability to the acromioclavicular joint via their attachment point for the coracoclavicular and coracoacromial ligaments.
The increased amount of freedom of motion in the shoulder necessitates some modifications in structure. The shoulder, as we have discussed, is a ball and socket joint similar to the hip joint. The difference lies in the requirements for mobility, which is much greater, in most instances, in the shoulder. Where the hip joint is stabilized very strongly by many ligamentous structures, the shoulder has more of a capsule surrounding the glenohumeral joint. This allows for a greater amount of overall mobility but it sacrifices the stability afforded the hip joint. There is a much greater emphasis on muscular stabilization of the shoulder joint via muscles such as supra/infraspinatus, teres minor and subscapularis.
Given the function of the upper limb, it should not be surprising that there are numerous muscular attachments for strong prime movers such as the pectoralis major and latissimus dorsi as well as long two-joint muscles like the biceps and triceps. Smaller scapular stabilizers such as the rhomboids and trapezius help to position the shoulder overall and the scapula in particular. The rotator cuff muscles- supraspinatus, infraspinatus, teres minor and subscapularis sit on the scapula in various locations. They function as shoulder rotators, but, more importantly, they stabilize or centre the humerus within the socket, or glenoid labrum.
Identify which muscles attach onto the coracoid process.
Biceps long head
We can start with palpation of the shoulder to find some of the most common shoulder structures that we discussed above.
Within the subacromial space sit a number of structures. This area is bordered superiorly by the acromion, inferiorly by the humeral head and medially by the coracoid. Repetitive overhead and cross body motions such as throwing or freestyle swimming decrease the available space in this already small space. Additional changes in scapulohumeral motion, weaknesses, limitations in motion and the like can all contribute to compression of the subacromial bursa within the space. This compression causes the bursa to swell, this swelling can lead to pain as well as reducing space in the small area, which all contribute to a reduction in range of motion.
Signs and symptoms
Pain with active and passive movements including flexion, abduction, internal rotation, cross flexion or any combination of motions that pinch the bursa. There may also be weakness in those motions due to pain in the shoulder. The patient may complain of pain at night as the bursa swells, which may wake them.
As a part of the rotator cuff muscle group supraspinatus acts to stabilize the humerus within the glenoid fossa, initiate abduction and assist in external shoulder rotation. The muscle and especially the tendon, sits in a compromising position under the subacromial space. With repeated overhead efforts the tendon may get pinched under the subacromial space causing fraying, irritation and pain. Positioning of the thoracic spine, scapula and humerus are all important contributors to subacromial space, or lack thereof, which must be corrected.
Supraspinatus tendon pain is usually localized to the anterior portion of the humerus but can refer pain down the anterior arm and even into the anterior chest. The pain may be sharp with movement or an overall ache at rest. Cross flexion and internal rotation motions, along with a painful arc, where the patient describes pain through an arc of 60-120 degrees of abduction, may be present. Rest will sometimes alleviate the pain but if severe enough the pain may be constant. Weakness with all shoulder motions, but especially the most painful, may be present.
The biceps tendons, but especially the long head, which attached onto the glenoid labrum, can also be irritated with overhead motions such as throwing or swimming. As the muscle helps stabilize the anterior shoulder, assist with shoulder flexion and elbow flexion/supination, and spans 2 joints, it is used a significant amount in all shoulder activity. The friction of the tendon under the bony subacromial space causes the familiar fraying and irritation of the tendon, creating symptoms similar to the impingement symptoms of the supraspinatus tendon.
Anterior shoulder pain is the hallmark of this condition. This pain may start as sharp pain, progressing to constant, dull aching, which may radiate distally into the arm.
Common in contact sports, the AC joint is typically injured via contact with the ground, boards or an immovable object, with the tip of the shoulder. This stresses the acromioclavicular, coracoclavicular and coracoacromial ligament complexes. Damage to these complexes creates varying amounts of dysfunction and deformity at the AC joint.
There are 6 grades of AC sprains. In an MSK setting one typically has clients who present with grade 1-3 sprains of the AC joint. Commonly higher grades involve more force such as motor vehicle or workplace injuries.
Signs and Symptoms
Typically, depending upon the severity of the injury the injured athlete may present with limitations in all shoulder motions, especially any cross body motions such as internal rotation, cross flexion and adduction. The unique aspect of more severe AC joint sprains is the presence of a 'step' deformity. This deformity is typically present in grades 2 and 3.
The lower grade injuries are managed conservatively i.e. non-surgically. Higher grades may involve surgical intervention, but as always it depends upon the specific case.
As with any injury to the AC one must consider alternate or differential diagnoses. The most obvious would involve a fracture of the clavicle or, in rare cases, a fracture of the humerus.
Similar to the AC joint sprain, the sternoclavicular or SC joint, is typically injured with contact to the tip of the shoulder. Most often clients describe landing on the tip of the shoulder with an external force, usually an opponent landing on their opposite shoulder, imparting a greater force. If that force does not injure the AC joint, it is then transmitted to the other end of the clavicle, the SC joint.
Signs and Symptoms
The SC joint, due to it's positioning on the sternum and the strong ligamentous support, tends to create a great deal of pain, dysfunction and disability. Clients present with local pain over the SC joint, along with swelling and potentially some ecchymosis. Once the swelling subsides, the client may present with a sort of step deformity where the clavicle sits more anterior than the sternum.
Ongoing issues may occur at the SC joint due to the change in positioning of the clavicle in the sternal notch. Alterations in the clavicular position change it's mechanics and accesorry motions. Though this may not seem significant, it does impact all other related components of the shoulder complex.
Differential diagnoses in this case include conditions such as brachial plexus injury, clavicle fractures and, in very extreme cases, injury to the underlying trachea.
As with other muscle injuries, most upper limb muscle strains take place as a result of an eccentric load to the muscle. Oftentimes the muscles most affected are 2 joint muscles e.g. biceps. Those muscles must function across 2 different joints e.g. elbow and shoulder, at the same time, while performing 2 different functions at those joints.
Signs and Symptoms
Most injuries to the muscle, whether in the muscle belly, musculotendinous junction or osteotendinous junction, are relatively minor. We typically observe grade 1 and 2 strains. They present with pain in the area, pain with movement, weakness with muscle contraction. In more severe instances we see swelling, ecchymosis and palpable deficits in the area of strain. With complete grade 3 strains where there is a rupture in the muscle, tendon or junction we may even observe a limit in function, where the muscle cannot perform it's normal function, creating an absence of joint movement. There may be joint movement as a result of other secondary muscles in the area that perform the same action.
Subluxations or dislocations are a relatively common injury in the glenohumeral joint. In this joint the humerus can move out of position in relation to the glenoid fossa for a variety of reasons including the relatively flat glenoid articulating with a round humeral head, the mobility of the gh joint and the reliance on muscular stabilization of the gh joint. Dislocations or subluxations can occur in a variety of directions- anterior, posterior or inferiorly. Most commonly the humerus moves anteriorly via an external rotation force on an abducted shoulder. Inferior subluxations or dislocations are a result of a traction force on the arm. Finally posterior dislocations occur subsequent to an adducted and/or internally rotated force, commonly a fall in this position. Oftentimes with shoulder subluxations or dislocations there is a concomitant injury to the glenoid labrum.
Signs and Symptoms
Shoulder disclocations present with varying amounts of pain. Some have severe amounts while others present with more of a 'shocky', understated pain profile. Typically there is a flattening of the deltoid which is both visible and palpable. This is most common in the instance of anterior dislocations.
All clients present with a limitation in active range and strength of the shoulder. One must be careful to check for distal pulse patency as occasionally the axillary artery can be impacted by gh dislocations. This situation necessitates immediate reduction. The examiner must also assess for changes in the skin sensation over the area of the 'sargeant's patch' of the deltoid.
There are a variety of injury mechanisms that cause fractures. There are a varied numbers and types of bones in the body. Even around the shoulder there are a number of types of different bones; long- humerus, flat- scapula, and the clavicle. The shoulder bones can be fractured via a direct blow to the bone, an indirect force such as a FOOSH (Fall On OutStretched Hand) injury or even a rotational, twisting mechanism.
Fractures in the shoulder, as in most areas of the body, come with pain. Pain alone cannot be the primary symptom. The client may present with deformity in the area, weakness, limitation of active range of motion, crepitus in the area with movement and swelling. Eventually they may develop ecchymosis in the region.
Muscle injuries normally occur in this part of the muscle unit.
Brachial plexus- Stinger, burner
Nerve injures in sport are not common in sport. They can occur as a consequence of a specific mechanism- traction, contusion or pressure, or may be a result of postural dysfunctions causing nerve issues. One of the more common injuries, especially in contact sports, is an injury to the brachial plexus commonly called a singer or burner. This injury has 3 different MOI including: 1. Sideflexion of the head away from the affected arm, along with traction to the upper limb 2. Direct compression or contusion to the brachial plexus 3. Sideflexion of the head toward the affected arm causing compression to the brachial plexus.
Signs and Symptoms
Brachial plexus injuries present with a significant amount of weakness in the shoulder. They typically describe a 'burning or stinging' sensation through the upper limb which may extend down to the fingers. This may be transient or may be present for an extended period of time. There may be tenderness on palpation in the region of the brachial plexus. They may also have tenderness on palpation in the cervical spine at the level of the injury to the nerve root in question. More specific testing should include myotome, dermatome and reflex testing to identify any deficits.
Thoracic Outlet Syndrome (TOS)
The thoracic outlet, the region deep to the clavicle and just lateral to the cervicothoracic junction, is an area that contains the brachial plexus and subclavian vessels serving the upper extremity. Various structures, some soft tissue other bony, in that area can cause compression to those neurovascular structures. This compression can be a result of anatomical anomalies, an extra cervical rib, posture related tightness of anterior and lateral soft tissue structures, pec minor, scalenes and upper trapezius, and other tumor related pathologies.
Signs and Symptoms
Those clients with TOS can present with a number of symptoms. These include temperature changes in the upper extremity, weakness in the upper limb, tingling, burning and numbness, some may also have associated pain in the thoracic outlet region or tightness in that same area.
For the shoulder joint, one must consider the joints above and below. This includes active movements of the cervical spine- flexion, extension, rotation, sideflexion with overpressure on all motions except extension. The elbow motions include flexion, extension, pronation and supination with overpressure. Remember that you are looking to reproduce the client's pain at the shoulder with the rule outs. If they do not produce pain then we consider them to be clear. If not the joint in question requires further investigation.
Due to the intimate interaction between thoracic cage mechanics and the shoulder, most times we will also evaluate the thoracic spine motion as it will be an area to address in our rehabilitation plan to correct the shoulder mechanics and injury. This is especially true in clients who present with insidious onset issues and/or overhead athletes.
Motions to be completed by the client include:
Flexion, extension, abduction, adduction, internal/external rotation, cross flexion/extension
We also need to consider the shoulder girdle as well. Those movements include elevation, depression, protraction and retraction.
These motions can be performed in a seated or standing position and performed on the injured and uninjured sides.
All of the motions above should be performed by the therapist for the patient. Care must be taken to move the client through a full range of motion, identifying when pain occurs in the range, what type of pain occurs, if there are any noises or other sensations and also the end feel at each range. These tests should be done with the patient in a supine position.
Testing for strength in the shoulder should be done in a neutral position within each range. These tests can also be performed with the patient in a supine position. This allows you to control the patient, use good body mechanics and support their limb.
Identify which movement would not be tested actively at the shoulder during your assessment.
Please appreciate that some of the video tests below show incorrect therapist body position for the sake of the viewer being able to see the test being performed.
Impingement- Hawkins- Kennedy and Neer
Identify on the picture you would palpate to identify the coracoid processes?
AC Joint Compression
Rotator Cuff Testing
Neural Tension- Upper
1. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 200, Public Domain, https://commons.wikimedia.org/w/index.php?curid=792173
2. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 207, Public Domain, https://commons.wikimedia.org/w/index.php?curid=327856
3. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 208, Public Domain, https://commons.wikimedia.org/w/index.php?curid=327860
4. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 205, Public Domain, https://commons.wikimedia.org/w/index.php?curid=24827050
5. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 326, Public Domain, https://commons.wikimedia.org/w/index.php?curid=85420
6. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 410, Public Domain, https://commons.wikimedia.org/w/index.php?curid=975527
7. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 411, Public Domain, https://commons.wikimedia.org/w/index.php?curid=37567713
8. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 412, Public Domain, https://commons.wikimedia.org/w/index.php?curid=527328
9. “Shoulder palpation.” YouTube video, 5:47. Posted by UWTherapy1, February 3, 2016. https://youtu.be/efFjdNnEiWg
10. By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 327, Public Domain, https://commons.wikimedia.org/w/index.php?curid=108237
11. By James Heilman, MD - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10314039
12. Personal photo. AC sprain. ND. JPEG file.
13. Personal photo, Post-op AC repair. ND. JPEG.
14. By MB (Collection personnelle) [CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons
15. By Nicholas Zaorsky, M.D. - Nicholas Zaorsky, M.D., CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15520323
16. By Grant, John Charles Boileu - An atlas of anatomy, / by regions 1962, Public Domain, https://commons.wikimedia.org/w/index.php?curid=29917834
17. “Impingement tests.” YouTube video, 2:04. Posted by UWTherapy1, February 3, 2016, https://youtu.be/QjZ3nuErmcE .
18. “Scapulohumeral Rhythm.” YouTube video, 1:43. Posted by UWTherapy1, February 3, 2016, https://youtu.be/pXiA735zis8 .
19. “Instability Tests.” YouTube video, 0:56. Posted by UWTherapy1, February 3, 2016, https://youtu.be/PXnWo2ovs2Y.
20. “Apprehension and Relocation.” YouTube video, 3:22. Posted by UWTherapy1, February 3, 2016, https://youtu.be/-cFe8wov0Ak .
21. “ACJ Compression.” YouTube video, 0:30. Posted by UWTherapy1, February 3, 2016, https://youtu.be/VOBaOPp-mqc?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN .
22. “Rotator Cuff Testing.” YouTube video, 1:17. Posted by UWTherapy1, February 3, 2016, https://youtu.be/gIhCAeFS6b8?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN .
23. “O’Brien’s Labral Test.” YouTube video, 0:43. Posted by UWTherapy1, February 3, 2016, https://youtu.be/koRFaUcAL8g?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN.
24. “Scouring.” YouTube video, 0:35. Posted by UWTherapy1, February 3, 2016, https://youtu.be/ydN7OnczVXk?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN.
25. “Nerve Tension Tests.” YouTube video, 1:31. Posted by UWTherapy1, February 3, 2016, https://youtu.be/ydN7OnczVXk?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN.
26. “Adson and Allen's TOS Tests.” YouTube video, 1:00. Posted by UWTherapy1, February 3, 2016, https://youtu.be/QPX78ZLIQY4?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN .
27. “Rhomboid/Trapezius Testing.” YouTube video, 0:55. Posted by UWTherapy1, February 3, 2016, https://youtu.be/s7AIQP2XXGQ?list=PLV29bbncwyTj9jFB3JvuEfyUaZteyAdeN.
28. “Upper Myotomes.” YouTube video, 0:49. Posted by UWTherapy1, March 8, 2016, https://youtu.be/Bz74F13yk9Q?list=PLV29bbncwyTiINIaYJ7BCgZlmSxLdpZEE.
29. “Upper Dermatomes.” YouTube video, 0:38. Posted by UWTherapy1, March 8, 2016, https://youtu.be/Bz74F13yk9Q?list=PLV29bbncwyTiINIaYJ7BCgZlmSxLdpZEE.
30. “Upper Reflexes.” YouTube video, 0:52. Posted by UWTherapy1, March 8, 2016, https://youtu.be/Tls8RvnxQB0?list=PLV29bbncwyTiINIaYJ7BCgZlmSxLdpZEE.