the shoulder complex

muscles of the shoulder complex: lateral rotation

-infraspinatus -teres minor

muscles of the shoulder complex: extension

-latissimus dorsi -teres major -posterior deltoid

muscles of the shoulder complex: scapular depression and adduction

-lower trapezius

muscles of the shoulder complex: scapular adduction

-middle trapezius -rhomboid major

muscles of the shoulder complex: flexion

-pectoralis major -anterior deltoid -biceps

muscles of the shoulder complex: medial rotation

-pectoralis major -subscapularis -latissimus dorsi -teres major

muscles of the shoulder complex: adduction

-pectroalis major latissimus dorsi

muscles of the shoulder complex: shoulder horizontal abduction

-posterior deltoid -latissumus dorsi -teres minor

muscles of the shoulder complex: scapular adduction and downward rotation

-rhomboid major -rhomboid minor

muscles of the shoulder complex: abduction

-supraspinatus -middle deltoid

muscles of the shoulder complex: scapular elevation

-trapezius -levator scapulae

shoulder stabilizing ligaments

Ligaments at each of the four articulations act collectively to provide stability to the shoulder complex.

deceleration phase

The deceleration phase lasts from ball release until maximum shoulder internal rotation. During this phase, the external rotators of the rotator cuff contract eccentrically to decelerate the humerus. The rhomboids contract eccentrically to decelerate the scapula. Most throwing injuries occur during either the acceleration phase of the deceleration phase.

apprehension test

With the arm abducted 90 degrees, the shoulder is slowly and gently externally rotated as far as the athlete will allow. The athlete with a history of anterior glenohumeral instability shows great apprehension that is reflected by a facial grimace before an endpoint can be reached. At no time should this movement be forced

test for sternoclavicular joint instability

With the patient sitting, pressure is applied anteriorly, then superiorly, and then inferiorly to the proximal clavicle to determine any instability or increased pain associated with a sprain. Pressure applied to the tip of the shoulder in a medial direction may also increase pain.

muscles of the shoulder complex: shoulder horizontal adduction

anterior deltoid -pectoralis major -coracobrachialis

muscles of the shoulder complex: scapular abduction and upward rotation

serrates anterior

assessing the shoulder complex: anterior observation

• Are both shoulder tips even with one another, or is one depressed? • Is one shoulder held higher because of muscle spasm or guarding? • Does one shoulder look square relative to the other, which is more rounded (indicating a shoulder dislocation)? • Is the lateral end of the clavicle easily visable (indicating acromioclavicular sprain or dislocation)? • Is one lateral acromion process more easily visable than the other (indicating a possible glenohumeral dislocation)? • Does the clavicular shaft appear deformed (indicating possible fracture)? • Is there loss of the normal lateral deltoid muscle contour (indicating glenohumeral dislocation)? • Is there an indentation in the upper biceps region (indicating rupture of biceps tendon)?

assessing the shoulder complex: posterior observation

• Is there asymmetry such as a low shoulder or an uneven scapulae (indicating postural scoliosis)? • Is the scapula protracted because of constricted pectoral muscles? • Is there a distracted or winged scapula on one or both sides? A winged scapula on both sides could indicate a general weakness of the serratus anterior muscles; if only one side is winged, the long thoracic nerve may be injured

assessing the shoulder complex: lateral observation

• Is there thoracic kyphosis or are the shoulders slumped forward (indicating weakness of the erector muscles of the spine and tightness in the pectoral region)? • Is there forward or backward arm hang (indicating possible scoliosis)?

assessing the shoulder complex: special tests

A number of special tests can help to determine the nature of an injury to the shoulder complex. The shoulder's active and passive range of motion should be noted and compared to the opposite side. Strength of the shoulder musculature should be assessed by resisted manual muscle testing. Both the muscles that act on the glenohumeral joint and those that act on the scapula should be tested.

glenohumeral joint

At the glenohumeral joint (the true shoulder joint), the round head of the humerus articulates with the shallow glenoid cavity of the scapula. The position of the glenohumeral joint is maintained by the surrounding glenohumeral ligaments that form the joint capsule and by the rotator cuff muscles.

tests for shoulder impingement

Forced flexion and adduction of the humerus in the overhead position may cause impingement of soft tissue structures between the humeral head and the coracoacromial ligament. A second test involves horizontal adduction with forced internal rotation of the humerus that also produces impingement. A positive sign is indicated if the athlete feels pain and reacts with a grimace.

preventing shoulder techniques

In particular, emphasis should be placed on strengthening the muscles of the rotator cuff to improve dynamic function and control in overhead activities such as throwing and swimming. Likewise, attention should be given to strengthening the scapular stabilizers by incorporating exercises to resist scapular abduction, adduction, elevation, depression, upward rotation, and downward rotation. Strengthening the muscles that control the stability of the scapula helps provide a base for the function of the highly mobile glenohumeral joint. Proximal stability is required for pain-free distal mobility. Proper warm-up must be performed before dynamic arm movements are attempted. This warm-up causes a general increase in body temperature and is followed by sport-specific stretching of selected muscles

assessing the shoulder complex: palpation

Palpation of the bony structures should be done with the examiner standing in front of and then behind the athlete. Both shoulders are palpated at the same time for pain sites and deformities. Palpation of the muscles around the shoulder detects point tenderness, abnormal swelling or lumps, muscle spasm or guarding, and trigger points. The shoulder is then also palpated anteriorly and posteriorly.

acceleration phase

The acceleration phase lasts from maximum external rotation until ball release. The humerus abducts, horizontally abducts, and internally rotates at velocities approaching 8000 degrees per second. The scapula elevates, abducts, and upward rotates.

acromioclavicular joint

The acromioclavicular joint is a gliding articulation of the lateral end of the clavicle with the acromion process of the scapula. This junction is rather weak. The acromioclavicular ligament along with the coracoclavicular ligament helps to maintain the position of the clavicle relative to the acromion. The coracoacromial ligament connects the coracoid to the acromion. This ligament along with the acromion forms the coracoacromial arch.

test for acromioclavicular joint instability

The acromioclavicular joint is first palpated to determine whether there is any displacement of the acromion process and the distal head of the clavicle. Next, pressure is applied to the distal clavicle in all four directions to determine stability and any associated increase in pain. Pressure is applied to the tip of the shoulder, which compresses the acromioclavicular joint and may also increase pain.

assessing the shoulder complex: observation

The athlete should be generally observed while walking and standing. Observation during walking can reveal asymmetry of arm swing or a lean toward the painful shoulder. The athlete is next observed from the front, side, and back while in a standing position. Observe for postural asymmetries, bony or joint deformities, or muscle spasm or guarding patterns.

shoulder bones

The bones that comprise the shoulder complex and shoulder joint are the clavicle, scapula, and humerus. These three bones form the four major articulations associated with the shoulder complex: the sternoclavicular joint, the acromioclavicular joint, the glenohumeral joint, and the scapulothoracic joint.

clavicle

The clavicle articulates with the sternum to form the sternoclavicular joint, the only direct connection between the upper extremity and the trunk. The sternoclavicular joint is extremely weak because of its bony arrangement, but it is held securely by the sternoclavicular ligament that pulls the clavicle downward and toward the sternum, in effect anchoring it. The clavicle is permitted to move up and down, forward and backward, and in rotation

cocking phase

The cocking phase begins when the hands separate and ends when maximum external rotation of the humerus has occurred. During this phase, the foot comes in contact with the ground.

test for supraspinatus muscle weakness

The empty can test for supraspinatus muscle strength has the athlete bring both arms into 90 degrees of forward flexion and 30 degrees of horizontal adduction. In this position, the arms are internally rotated as far as possible, thumbs pointing downward. A downward pressure is then applied. Weakness and pain can be detected as well as comparative strength between the two arms.

follow-through phase

The follow-through phase lasts from maximum shoulder internal rotation until the end of the motion, when there is a balanced position.

assessing the shoulder complex: history

The following questions in regard to the athlete's complaints can help determine the nature of the injury: • What happened to cause this pain? • Have you ever had this problem before ? • What is the duration and intensity of the pain? • Where is the pain located? • Is there crepitus during movement or numbness or distortion in temperature such as a cold or warm feeling? • Is there a feeling of weakness or a sense of fatigue? • What shoulder movements or positions seem to aggravate or relieve the pain? • If therapy has been given before, what, if anything, offered pain relief (e.g., cold, heat, massage, or analgesic medication)? • Have there been any recent changes in the training program?

muscles

The muscles that cross the glenohumeral joint pro- duce dynamic motion and establish stability to compensate for a boy and ligamentous arrangement that allows for a great deal of mobility. Movements at the glenohumeral joint include flexion, extension, abduction, adduction, and rotation. The muscles acting on the glenohumeral joint can be separated into three groups. The first group consists of muscles that originate on the axial skeleton and attach to the humerus, including the latissimus dorsi and the pectoralis major. The second group originates on the scapula and attaches to the humerus, including the deltoid, the teres major, the coracobrachialis, and the rotator cuff (subscapularis, supraspinatus, infraspinatus, teres minor). A third group of muscles attach the axial skeleton to the scapula and includes the levator scapula, the trapezius, the rhomboids, and the serratus anterior and posterior. The scapular muscles are important in providing dynamic stability to the shoulder complex

scapulothoracic joint

The scapulothoracic joint is not a true joint; however, the movement of the scapula on the wall of the thoracic cage is critical to shoulder joint motion. Contraction of the scapular muscles that attach the scapula to the axial skeleton is critical in stabilizing the scapula, thus providing a base on which a highly mobile glenohumeral joint can function.

wind-up phase

The wind-up or preparation phase lasts from the first movement until the ball leaves the gloved hand. During this phase, the lead leg strides forward. Both shoulders abducted, externally rotate, and horizontally abduct.

using correct throwing techniques

To prevent overuse shoulder injuries, it is essential that athletes be correctly taught the appropriate techniques of throwing a baseball or football, throwing a javelin, serving or spiking a volleyball, and serving or hitting an overhead smash in tennis. If the thrower uses faulty technique, the joints are affected by atypical stresses that result in trauma to the joint and its surrounding tissues. Relative to the shoulder complex, throwing involves five distinct phases: wind-up, cocking, arm acceleration, arm deceleration, and follow-through

sternoclavicular joint sprain

cause of injury A sternoclavicular sprain is a relatively uncommon occurrence in sports. The mechanism of the injury is either an indirect force transmitted through the humerus, the shoulder joint, and the clavicle, or a direct impact to the clavicle. Usually the clavicle is displaced upward and forward. signs of injury A sprain to the sternoclavicular joint can be described in three degrees. A grade 1 sprain is characterized by little pain and disability, with some point tenderness but no joint deformity. A grade 2 sprain displays subluxation of the sternoclavicular joint with visible deformity, pain, swelling, point tenderness, and an inability to abduct the shoulder through a full range of motion or to bring the arm across the chest, indicating disruption of the stabilizing ligaments. The grade 3 sprain, which is the most severe, presents a picture of complete dislocation with gross displacement of the clavicle at its sternal junction, swelling, and disability, indicating complete rupture of the sternoclavicular ligament. A posterior or "retro -sternal" dislocation of the clavicle is rare but has the potential to be a life-threatening injury due to hemorrhage and compromise of the nearby trachea care PRICE should be used immediately, followed by immobilization. Immobilization is usually maintained for 3 to 5 weeks, followed by graded reconditioning exercises. There is a high incidence of recurrence of sternoclavicular sprains.

clavicle fractures

cause of injury Clavicular fractures are one of the most frequent fractures in sports. Fractures of the clavicle result from a fall on the outstretched arm, a fall on the tip of the shoulder, or a direct impact. They most often occur in the middle ½ of the clavicle. signs of injury The athlete with a fractured clavicle usually supports the arm on the injured side and tilts his or her head toward that side, with the chin turned to the opposite side. During inspection, the injured clavicle appears a little lower than the unaffected side. Palpation may also reveal swelling, point tenderness, and mild deformity. care The clavicular fracture is cared for immediately by applying a shoulder immobilizer and by treating the athlete for shock, if necessary. If X-ray examination reveals a fracture, a closed reduction should be attempted by the physician, followed by immobilization with a clavicle strap. Immobilization should be maintained for 6 to 8 weeks. Following this period of immobilization, gentle isometric and mobilization exercises should begin with the athlete using a sling for an additional 3 to 4 weeks to provide protection. Occasionally, clavicle fractures may require operative management.

fractures of the humerus

cause of injury Fractures of the humerus happen occasionally in sports, usually as the result of a direct blow, a dislocation, or the impact of falling onto the outstretched arm. signs of injury A fracture of the humerus is difficult to recognize by visual inspection alone ; X-ray examination gives the only positive proof. Some of the more prevalent signs that may be present are pain, inability to move the arm, swelling, point tenderness, and discoloration of the superficial tissue. care Recognition of humeral shaft fractures requires immediate application of a splint or immediate support with a sling, treatment for shock, and referral to a physician. The athlete with a fracture to the humerus will be out of competition for approximately 2 to 6 months, depending on the location and severity of the fracture.

shoulder impingement syndrome

cause of injury Shoulder impingement involves a mechanical compression of the supraspinatus tendon, the subacromial bursa, and the long head of the biceps tendon, all of which are located under the coracoacromial arch. Repetitive compression eventually leads to irritation and inflammation of these structures. Impingement most often occurs in repetitive overhead activities such as throwing, swimming, serving a tennis ball, or spiking a volleyball. Signs of Injury The athlete complains of diffuse pain around the acromion whenever the arm is in an overhead position. There may be a painful arc in the range of motion between 70 and 120 degrees of abduction. The external rotators are generally weaker than the internal rotators. There may be some tightness in the posterior and inferior joint capsule. There usually is a positive impingement test, and the empty can test may increase pain. care Management of impingement involves restoring normal biomechanics to the shoulder joint in an effort to maintain space under the coracoacromial arch during overhead activities. PRICE can be used to modulate pain initially. Exercises should concentrate on strengthening the rotator cuff muscles and those muscles that produce movement of the scapula, and on stretching the posterior and inferior joint capsule. The activity that caused the problem in the first place should be modified so that the athlete has initial control over the frequency and the level of the activity, with a gradual and progressive increase in intensity.

acromioclavicular joint sprain

cause of injury The acromioclavicular extremely vulnerable to sprains, especially in collision sports. The primary mechanisms are a fall on an outstretched arm or direct impact to the tip of the shoulder that forces the acromion process downward, backward, and inward while the clavicle is pushed down against the rib cage signs of injury -In a grade 1 acromioclavicular sprain, there is point tenderness and discomfort during movement at the junction between the acromion process and the outer end of the clavicle. There is no deformity, indicating only mild stretching of the acromioclavicular ligaments -A grade 2 sprain shows definite displacement and prominence of the lateral end of the clavicle when compared to the unaffected side. There is point tenderness during palpation of the injury site, and the athlete is unable to fully abduct through a full range of motion or to bring the arm completely across the chest -A grade 3 sprain involves rupture of the acromioclavicular and coracoclavicular ligaments with dislocation of the clavicle. Such an injury has gross deformity and prominence of the distal clavicle, severe pain, loss of movement, and instability of the shoulder complex care Immediate care of the acromioclavicular sprain involves three basic procedures: (1) application of cold and pressure to control local hemorrhage, (2) stabilization of the joint by a shoulder immobilizer , and (3) referral to a physician for definitive diagnosis and treatment. 22 Immobilization ranges from 3 to 4 days with a grade 1 to approximately 2 weeks with a grade 3. With all grades, an aggressive rehabilitation program involving joint mobilization, flexibility exercises, and strengthening exercises should begin immediately following the recommended period of protection. Progression should be as rapid as the athlete can tolerate without increased pain or swelling.

glenohumeral dislocations

cause of injury The most common glenohumeral dislocation is one in which the head of the humerus is forced out of its joint capsule in an anterior direction past the glenoid labrum and then downward to rest under the coracoid process. The mechanism for an anterior dislocation is abduction, external rotation, and extension that forces the humeral head out of the glenoid cavity. An arm tackle in football or rugby or abnormal forces created in executing a throw can produce a sequence of events resulting in dislocation. On rare occasion, the humerus dislocates in an inferior direction. Once an athlete has suffered a glenohumeral dislocation, he or she faces a high probability of recurrence because of chronic instability resulting from stretching or tearing of the glenohumeral joint capsule, the glenohumeral ligaments, defects in the glenoid labrum or weakness of the rotator cuff muscles that function to dynamically stabilize the glenohumeral joint. signs of injury The athlete with an anterior dislocation displays a flattened deltoid contour. Palpation of the axilla reveals prominence of the humeral head. The athlete carries the affected arm in slight abduction and external rotation and is unable to touch the opposite shoulder with the hand of the affected arm. There is often moderate to severe pain and disability. care Initial management of the shoulder dislocation requires immediate immobilization in a position of comfort using a sling; immediate reduction by a physician; and control of the hemorrhage by cold packs. After the dislocation has been reduced and immobilized, muscle reconditioning should be initiated as soon as possible. Protective sling immobilization should continue for approximately 1 week after reduction. The athlete is instructed to begin a strengthening program, progressing as quickly as pain allows. Protective shoulder braces may help limit shoulder motion

rotator cuff strains

cause of injury The most common rotator cuff tendon strain involves the supraspinatus muscle, although any of the rotator cuff tendons are subject to injury. The mechanism of rotator cuff strains involves dynamic rotation of the arm at a high velocity, as occurs during overhead throwing or any other activity in which there is rotation of the humerus. Most rotator cuff tears occur in the supraspinatus in individuals with a long history of shoulder impingement or instability and are relatively uncommon in athletes under the age of 40. Tears of the rotator cuff muscles are almost always near their insertion on the humerus. signs of injury Like other muscle strains, rotator cuff strains present pain with muscle contraction, some tenderness on palpation, and loss of strength because of pain. A tear or complete rupture of one of the rotator cuff tendons produces an extremely disabling condition in which pain, loss of function, swelling, and point tenderness are symptoms. In the case of a tear of the supraspinatus tendon, both the impingement tests and the empty can test are positive. care PRICE can be used to modulate pain initially. Exercises should concentrate on progressive strengthening of the rotator cuff muscles. The frequency and level of the activity should be reduced initially, with a gradual and progressive increase in intensity.