SHOULDER

CHAPTER FOUR SHOULDER

INTRODUCTION

The shoulder is a system of joints, and many movements of this system involve the neck. Completely independent action of the shoulder is possible, but independent, simultaneous action of the shoulder and neck is not.

The glenohumeral joint may be affected as part of widespread joint disease (i.e., a polyarthropathy such as rheumatoid arthritis, crystal deposition disease arthropathy, other inflammatory arthropathies, or generalized osteoarthritis). Periarticular conditions can be grouped into categories with and without capsulitis. In the absence of capsular involvement, passive joint motion is largely unaffected, whereas active movement may be limited by pain or weakness or both. In the presence of capsulitis, multidirectional restriction of passive motion is seen. Clinical and radiologic studies differentiate these conditions from articular conditions.

Referred pain to the shoulder can occur with cervical disorders, Pancoast tumor of the lung, a subphrenic pathologic condition, entrapment neuropathies, myofascial pain syndromes, and brachial neuritis (Table 4-3).

TABLE 4-3 COMMON CAUSES OF SHOULDER PAIN

Periarticular Disorders	Regional Disorders	Glenohumeral Disorders
Rotator cuff tendinitis/impingement syndrome Calcific tendinitis Rotator cuff tear Bicipital tendinitis Acromioclavicular arthritis	Cervical radiculopathy Brachial neuritis Nerve entrapment syndromes Sternoclavicular arthritis Reflex sympathetic dystrophy Fibrositis Neoplasms Miscellaneous: Gallbladder disease Splenic trauma Subphrenic abscess Myocardial infarction Thyroid disease Diabetes mellitus Renal osteodystrophy	Inflammatory arthritis Osteoarthritis Osteonecrosis Cuff arthropathy Septic arthritis Glenoid labrum tears Adhesive capsulitis Glenohumeral instability

From Kelley WN, et al: Textbook of rheumatology, ed 5, Philadelphia, 1997, WB Saunders.

Identification of the primary cause of shoulder pain is not always easy. Referred pain to the shoulder girdle region occurs from multiple sources other than the neck. With diaphragmatic irritation, pain is referred along the phrenic nerve to the supraclavicular region, the trapezius, and the superomedial angle of the scapula. Gastric and pancreatic diseases may refer pain to the interscapular region. The rare superior sulcus lung tumor, or Pancoast tumor, occasionally coincident with Horner syndrome, may have shoulder pain as its initial symptom.

TABLE 4-1 SHOULDER JOINT CROSS-REFERENCE TABLE BY ASSESSMENT PROCEDURE

TABLE 4-2 SHOULDER JOINT CROSS-REFERENCE TABLE BY SYNDROME OR TISSUE

The arm as a lever is useless unless it has a fixed base. The fixed base comes largely from the layers of flat muscles piled one on top of another and attached to all surfaces of the scapula.

Paralytic disorders implicating these muscles come into clinical focus when weakness in the fixation mechanism is demonstrated. The serratus anterior, when paralyzed, allows the scapula to swing backward and loosen its attachment to the chest. The trapezius allows the scapula to spin like a pinwheel, which contributes to the loss of fixation.

The mobility of this part of the body results from the configuration of the bony parts and the mechanically advantageous attachment of the multiple muscles. The shallow socket and ball head favor frictionless spinning, and the main joint has four accessory articulating zones that complement and enhance the action of the shoulder.

Everyday activities are made up of acts such as lifting, holding, pushing, turning, and shoving. Through such common and accepted motions, clinical disorders are manifested. These activities are combined pattern motions with contributions from many parts of the shoulder complex. Individual joint and muscle contribution may be analyzed in these acts to aid localization and understanding of injury and disease. Consideration must also be given to the part that the elbow and hand play in shoulder function. Shoulders are used unconsciously during actions of the hand, wrist, and elbow. Injury or disease may hamper normal action of any of these areas; therefore, increased replacement effort is sought from the shoulder. For example, loss of rotatory range, as in arthrodesis of the wrist or elbow, unconsciously results in increased rotation at the shoulder. Weakness or disorder of one muscle group evokes replacement effort in another group. For example, the hunching motion by the trapezius that follows attempted abduction is a replacement effort associated with paralysis of the deltoid. Scrutiny of these purposeful patterns is of great help in understanding disability in this region.

Chronic overuse syndromes with repetitive stretching, as in rowing, swimming, or throwing, are injuries of repetitive microtrauma. Atraumatic disorders generally result from ligamentous laxity or congenital hypoplasia of the glenoid. Impact injuries may be divided into direct and indirect trauma. For direct trauma, the injury force is in direct contact with the shoulder complex. Indirect forces injuring the shoulder usually pass up through the hand, wrist, or elbow and result in a rotational or longitudinal force directed along the humerus.

ESSENTIAL ANATOMY

The shoulder joint is a ball-and-socket joint that is the articulation of the humerus and the glenoid fossa of the scapula. To describe the anatomy of the shoulder joint, the term shoulder joint complex may be more accurate. The shoulder joint complex really consists of four joints: the glenohumeral, the acromioclavicular, the sternoclavicular, and the scapulothoracic articulation. The acromioclavicular joint is formed by the lateral end of the clavicle and acromion. The acromioclavicular joint is reinforced by the surrounding capsule and ligaments, containing an anterior, posterior, superior, and inferior component, in addition to the coracoclavicular ligaments, which are made up of two individual ligaments: the coracoid and trapezoid ligaments. The short head of the biceps arises with the coracobrachialis from the scapular coracoid process and runs down the medial side of the long head of the biceps. The two bellies join as a common distal tendon just above the elbow joint as a flattened tendon, only to separate into two distal insertions.

ESSENTIAL MOTION ASSESSMENT

Shoulder motion is interpreted through excursion of the arm from the body and is recorded according to the anatomic planes (Fig. 4-1).

FIG. 4-1 Range of motion of the shoulder. A, Forward flexion and extension. B, Abduction and adduction. C, Internal rotation. D, External rotation.

ORTHOPEDIC GAMUT 4-3 SHOULDER MOVEMENTS

Primary shoulder movements are:

1. Elevation in the coronal (frontal) plane (abduction and adduction)

2. Flexion and extension in the sagittal plane (Figs. 4-2 and 4-3)

3. Horizontal adduction and abduction in the transverse (horizontal) plane (Figs. 4-4 and 4-5)

4. Internal and external rotation (torque around the humerus) (Figs. 4-6 and 4-7)

FIG. 4-2 Flexion is accomplished by the anterior deltoid, pectoralis major, coracobrachialis, and biceps. A retained flexion range of motion that is 160 degrees or less is an impairment of the shoulder in the activities of daily living.

FIG. 4-3 Forty degrees or less of retained extension range of motion is an impairment of the shoulder in the activities of daily living.

FIG. 4-4 Less than 160 degrees of retained abduction range of motion is an impairment of the shoulder in the activities of daily living.

FIG. 4-5 A retained adduction range of motion of 30 degrees or less is an impairment of the shoulder in the activities of daily living.

FIG. 4-6 External rotation is the most important action; and when this rotation is lost, shoulder action is seriously compromised. Sixty degrees or less of retained external rotation is an impairment of the shoulder in the activities of daily living.

FIG. 4-7

ESSENTIAL MUSCLE FUNCTION ASSESSMENT

The muscles surrounding the shoulder joint complex provide the ability to generate motion while simultaneously providing dynamic stability to the glenohumeral joint.

The teres major muscle arises from the lower third of the lateral border of the scapula and travels around the anterior aspect of the humerus and in front of the long head of the triceps to insert onto the crest of the lesser tubercle. The teres minor and deltoid receive their innervation by the axillary nerve, whereas the teres major is supplied by the lower subscapular nerve (Figs. 4-8 to 4-13).

FIG. 4-8 The examiner achieves immobilization by grasping and holding the lower border with one hand. The patient flexes the arm anteriorly to 90 degrees while the forearm is pronated and the elbow slightly flexed.

FIG. 4-9 Extension of the shoulder is tested with the patient’s elbow straightened and the forearm fully pronated (palm posterior) to prevent lateral rotation and adduction. The examiner fixes the scapula as described for testing flexion, and the patient extends the arm posteriorly through the range of motion.

FIG. 4-10 The patient abducts the arm to 90 degrees. This abduction occurs against graded resistance applied by the examiner’s other hand, which is placed proximal to the patient’s elbow.

FIG. 4-11 The patient adducts the arm anteriorly through the horizontal plane of motion and against graded resistance. This resistance is applied by the examiner’s other hand, which is placed over the front of the arm and proximal to the patient’s elbow.

FIG. 4-12 The external rotation of the shoulder is assessed with the patient’s arm abducted to 90 degrees (or at the patient’s side if abduction is not possible), with the elbow flexed to 90 degrees, and with the hand and fingers pointing forward.

FIG. 4-13 The examiner supports the patient’s elbow with one hand, as described previously, while the patient rotates the arm downward (or inward if the shoulder abduction is not possible) against graded resistance that is applied by the examiner’s other hand, which is placed on the patient’s forearm proximal to the wrist.

ORTHOPEDIC GAMUT 4-5 MUSCLE ATTACHMENTS

The scapula to spine muscle attachments are as follows:

2. Levator scapula

3. Rhomboid major

4. Rhomboid minor

5. Serratus anterior

ESSENTIAL IMAGING

The shoulder girdle consists of the two bones that attach the upper limb to the thoracic wall: the scapula and the clavicle. The glenoid fossa of the scapula forms the articulation of the shoulder girdle with the head of the humerus.

The most important films to obtain are the true anteroposterior (AP) and the modified West Point views. Both of these projections provide an excellent view of a glenohumeral joint. The examiner is able to appreciate the characteristic posterior glenoid wear. The acromioclavicular joint can be radiographically evaluated and correlated with the physical examination. The AP view should include the proximal two thirds of the humeral shaft so that the physician can safely estimate the appropriate humeral component diameter. When clinically indicated, the radiographic examination of the shoulder must include a cervical spine series.

PROCEDURE

• With the patient in the seated position, the examiner fully abducts and externally rotates the patient’s arm.

• The examiner then lowers the arm to the patient’s side (Fig. 4-14).

• A palpable or audible click indicates a subluxation or dislocation of the biceps tendon.

• While the examiner’s finger or fingers palpate for the point of maximal tenderness within the bicipital groove, the shoulder is alternately rotated.

• A positive test occurs in biceps tendinitis when the patient feels pain as the tendon glides beneath the examiner’s finger.

FIG. 4-14

The biceps tendon will not rupture or dislocate under ordinary stresses unless it is already weak. The predisposing factor to rupture or dislocation is age degeneration, which is probably accelerated by often-repeated friction and angulation at the point where the tendon enters the bicipital groove of the humerus.

ALLEN MANEUVER

Assessment for Thoracic Outlet Syndrome

ORTHOPEDIC GAMUT 4-8 THORACIC OUTLET SYNDROME CLASSIFICATIONS

Thoracic outlet syndrome (TOS) is categorized in three types:

• Vascular (vTOS). Unilateral arm swelling without thrombosis, when not caused by lymphatic obstruction, may be caused by subclavian vein compression at the costoclavicular ligament because of compression by either that ligament or the subclavius tendon most often because of congenital close proximity of the vein to the ligament. Patients with compression of the subclavian artery and vein are classified into two other groups as vascular TOS: arterial TOS or venous TOS.

• Neurogenic (nTOS) compromises the majority of these symptomatic individuals with brachial plexus and T1 nerve palsy. Neck trauma is also the most common cause of nTOS in patients with abnormal ribs. Involvement of the brachial plexus causes the nTOS that comprises two groups: one corresponding to patients harboring the true or classic signs and symptoms and electromyographic (EMG) findings (nTOS) and the other corresponding to patients with nonspecific clinical and EMG findings (nonspecific nTOS).

• Disputed neurogenic TOS (dnTOS). Upper extremity arterial compromise caused by this compacted thoracic outlet may also occur with a resulting limb ischemia. Patients often complain of a painful upper extremity after exercise albeit limb claudication symptoms. Discolored, pale, underperfused arms with absent or decreased arterial pulse is a common finding in these individuals with an arterial form of TOS. This group includes patients with signs and symptoms of posttraumatic neurovascular compression (Paget-Schroetter syndrome).

APLEY TEST (ALSO KNOWN AS APLEY SCRATCH TEST)

Assessment for Degenerative Tendinitis of One of the Tendons of the Rotator Cuff, Usually the Supraspinatus Tendon

APPREHENSION TEST

Assessment for Anterior Shoulder Dislocation Trauma and Posterior Dislocation of the Humerus

PROCEDURE

• The patient’s shoulder is abducted and externally rotated.

• If the patient shows apprehension or alarm and resists further motion, the test is positive (Fig. 4-19).

• This test may elicit a feeling that resembles the pain felt when the shoulder was previously dislocated.

• This test is performed slowly and cautiously; if the action is performed too quickly, the humerus may dislocate.

• Anterior shoulder dislocation trauma is suggested by a positive test.

• To evaluate posterior shoulder dislocation, the shoulder is flexed and internally rotated (Fig. 4-20).

• A posterior force is applied on the patient’s elbow.

• If the patient exhibits apprehension and resists further motion, the test is positive.

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Jun 5, 2016 | Posted by admin in ORTHOPEDIC | Comments Off

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