TIS                         
Chapter 10
The Shoulder


THE UPPER EXTREMITY IN CONTEXT & THE SHOULDER

Overview of the Upper Extremity: the primary function of the upper extremity is to position the hand for interaction with the environment.

The shoulder, similar to the hip, functions to position the hand, provides stability for hand use, lifts, pushes, elevates the body, assists with forced inspiration and expiration, and even weight bearing as in crutch-walking (Smith, Weiss, & Lehmkuhl, 1996, p. 223).

The elbow serves to shorten and lengthen the upper extremity. It is important in elevating the body, as in push-ups or pull-ups (Smith, Weiss, & Lehmkuhl, 1996, p.158).

The hand performs a significant range of functions. It is an organ for touch, an extension to the brain to provide information to the visual system about the environment, and it is an important organ for expression and nonverbal communication. The hand can grasp with forces exceeding 100 pounds as well as hold and manipulate a delicate thread (Smith, Weiss, & Lehmkuhl, 1996, p.180).

Shoulder Complex: The term "complex" is quite appropriate for the shoulder, which is comprised of three joints and one primary articulation, all moved by twenty muscles, permitting the greatest mobility of any joint in the human body. The three joints and primary articulation of the shoulder are:

The Sternoclavicular Joint: provides the only attachment for the upper extremity to the Axial skeleton. Functional Anatomy and Brief Biomechanical Considerations: the great degree of shoulder mobility exists at the expense of structural stability.

Glenohumeral Stability: The surface of the glenoid fossa is only one third to one fourth that of the humeral head, which means that only part of the humeral head is in contact with the glenoid at any given time (Culham & Peat, 1993). Because of this, there is little inherent bony stability in the glenohumeral joint. Stability of the joint is enhanced by a number of anatomic features, including: The joint capsule and glenohumeral movement: because the plane of the scapula is oriented midway between the frontal and sagittal planes, it places a twist on the joint capsule. Tension in the joint capsule increases with abduction, pulling the humerus into external rotation. This rotation allows for greater range of motion into abduction by allowing the greater tubercle to clear the coracoacromial arch. Abnormal tightness of the joint capsule, can greatly impair the normal biomechanical motion of the shoulder (Hertling & Kessler, 1996, p. 173).

Scapulothoracic-glenohumeral rhythm: ratio of glenohumeral movement to scapulothoracic movement in abduction is 2:1 (Smith, Weiss, & Lehmkuhl, 1996).

The purpose of scapulohumeral rhythm is to maintain the glenoid fossa in a optimal position to receive the head of the humerus, thus increasing range. The motion of the scapula permits muscles acting on the humerus to maintain a good length-tension relationship.

The Coracoacromial Arch: formed by the coracoid and acromion processes of the scapula and the coracoacromial ligament that unites them. The subacromial space, which exists between the coracoacromial arch and the humeral head is occupied by the supraspinatus, the long head of the biceps and the subacromial bursa. In normal subjects, this space measures 9 to 10 mm. A reduction in this space is associated with impingement of the structures within the subacromial space (Culham & Peat, 1993, p. 348).

The rotator cuff: the supraspinatus, infraspinatus, teres minor, and subscapularis.

Blood supply to the rotator cuff: the arterial and venous supply to the insertion of the rotator cuff muscles is poor, and is considered a "watershed" area, in which the cuff receives its blood supply indirectly from arteries above and below. The majority of rotator cuff tears occur at this "watershed" area, and healing time can obviously be impacted by this anatomical factor. This tenuous blood supply affects the supraspinatus muscle more greatly than the other muscles of the cuff.

The long head of the biceps: originates from the supraglenoid tubercle of the scapula and the superior aspect of the glenoid labrum, arches over the head of the humerus, and descends into the bicipital groove. With shoulder movements, primarily flexion, the biceps tendon does not slide in the bicipital groove, but the groove/humerus moves on the fixed tendon (Hammer, 1991, p. 45). Overload of the transverse humeral ligament may occur in abduction and external rotation, resulting in a subluxing tendon (Richardson & Iglarsh, 1994, p.196).

The thoracic outlet and the neurovascular bundle: the thoracic outlet is the region at the base of the neck through which pass the neurovascular bundle comprised of the brachial plexus and the subclavian vessels, which are in route to the upper extremity from the mediastinum. The brachial plexus and/or subclavian vessels can become entrapped by various anatomic structures, leading to a number of pathologies collectively known as Thoracic Outlet Syndrome (Kreig, 1993).

Symptoms of neurovascular compression due to Thoracic Outlet Syndrome are often vague and nonspecific, ranging from exertional fatigue to frank paresthesia and vascular insufficiency (Baker & Liu, 1993).

The Joint Capsule of the Shoulder: The entire glenohumeral joint is surrounded by a large, loose capsule, which in the resting position is taut superiorly and slack inferiorly. There is a slight negative pressure within the joint capsule, which may contribute somewhat to increasing glenohumeral joint stability. The resting position of the shoulder is 55 degrees abduction, 30 degrees horizontal adduction. Its closed packed position is full abduction and lateral rotation. The capsular pattern of the shoulder is external rotation, abduction, internal rotation (Magee, 1997, p. 175).

The tendons of the rotator cuff muscles blend with and reinforce the joint capsule (Culham & Peat, 1993).

Ligaments of the Shoulder Complex are extracapsular or intracapsular, and include the following:

Extracapsular Ligaments:

Intracapsular ligaments:

The glenohumeral ligaments: are thickenings of the joint capsule and provide a great deal of support to the weak joint capsule. These three ligaments form a "Z" to reinforce the capsule anteriorly.

Muscles: provide the dynamic stability to the joint.

Soft Tissue Disorders of the Shoulder

Shoulder instability: usually the result of injury to ligaments, muscles, and/or the glenoid labrum. Instability is defined by the direction of excessive humeral head movement. Factors that contribute to the degree of instability include: the amount of movement of the humeral head, whether the problem is chronic versus acute, whether the initial injury was traumatic or atraumatic in nature, and whether the person can voluntarily move the humeral head out of the glenoid. Shoulder instability can be due to a number of factors, including dislocations, subluxations, sprains, and strains.

Dislocations and Subluxations: Dislocation occurs when the articulating surfaces of the bones that comprise a joint lose contact with each other, usually due to an external force. Subluxation is a partial slip or slide of one articulating surface on another, with some degree of contact between the two articulating surfaces, which may or may not be painful.

Subluxation is commonly seen in the shoulders of people with hemiplegia, where loss of motor control to the muscles allows the scapula to downwardly rotate and tip anteriorly, positioning the glenoid fossa anteriorly and inferiorly, allowing the humeral head to be displaced inferiorly by gravity. Weakness/paresis of the rotator cuff in association with prolonged traction due to gravity stretches the capsule and ligaments of the joint. Treatment via Bobath sling, Functional Electrical Stimulation, and facilitation of the muscular components have some degree of effect, depending on the extent of the neurological insult.

Anterior Shoulder Dislocation: 98% of shoulder dislocations are anterior-inferior in direction:

Incidence of recurrence of dislocation is directly proportional to the magnitude of trauma required to produce the dislocation: the less trauma required to produce the initial dislocation, the more likely the shoulder is to remain unstable in activities with the arm in the overhead position.

Posterior Shoulder Dislocation: dislocations posteriorly are rare.

Signs and symptoms of shoulder dislocation (anterior and posterior) include loss of upper extremity function, positive apprehension test, positive sulcus sign, loss of normal contour of the shoulder, and potential sensory loss. Pain may or may not be present, depending on the chronicity of the dislocation.

Treatment of dislocations:

Acute phase: immediate reduction by a qualified person; ice, NSAIDS, immobilization for three to six weeks with ROM exercises at elbow, wrist, and hand; isometrics of the shoulder muscles.

Subacute phase: begin AROM in isolated planes; avoid positions that recreate position of dislocation;

Strengthening of muscles:

Pathologies associated with the Glenoid Labrum: usually the result of shoulder dislocations, and are associated with shoulder instability. Recurrent episodes of dislocation or subluxation may require surgical intervention.

Bankart Lesion: a condition in which the anterior band of the inferior glenohumeral ligament is avulsed along with a portion of the labrum from the glenoid, resulting in anterior-inferior instability (Hammer, 1991, p.51).

Hill Sach's Lesion: a lesion also associated with anterior inferior dislocation. A defect of the humeral head in which a portion of the posterior humeral head is fractured or compressed during dislocation. The depression caused by this defect "impales itself" on the glenoid and the labrum causing a bony lock. External rotation of the humerus can cause relocking of the shoulder, therefore therapists must be very careful when having patients perform this motion.

"SLAP" Lesion: a labral injury involving the superior aspect of the glenoid labrum, beginning posteriorly and extending anteriorly stopping at or above the mid-glenoid notch, which is associated with some degree of tearing of the tendon of the long head of the biceps.

Surgical intervention addresses the pathology precisely, reestablishing the pre-injury anatomy as much as possible. The glenoid is reattached to the bone via sutures, torn ligaments are sewn together and reattached. Some procedures, such as the Bristow procedure reinforces the stability via tendon transfers. With the Bristow procedure, an anterior buttress is created by transferring the conjoined tendons of the short head of the biceps and the coracobrachialis to the glenoid neck, so that during active abduction the conjoint tendon pulls across the front of the joint, dynamically stabilizing it (Reid, 1992, p. 973).

Sprains:

Acromioclavicular joint: most frequently sprained ligament of the shoulder. Mechanism of injury usually involves a direct fall or blow to the AC joint, a fall on the elbow or extended arm which drives the humerus superiorly.

Signs and symptoms: point tenderness over the AC joint, varying degrees of deformity from slight rise of the acromion to a "complete separation" of the shoulder. Pain with joint motion. The AC joint spring test and the shoulder depression test are positive.

Sternoclavicular joint: mechanism of injury involves a direct blow to the sternum, or an indirect force from a fall on the shoulder with the arm extended, or a lateral compression force. If the force is applied with slight retraction of the shoulder, the more common anterior SC sprain is acquired, if the force is applied with slight shoulder protraction, the result is a posterior sprain.

Signs and symptoms: localized pain over the SC joint, pain with motion of the shoulder joint, varying degrees of deformity depending on grade of sprain. The squeeze test is positive.

Treatment for Sprains of the Shoulder: the joint is routinely immobilized for 2 to 4 weeks; inflammatory control during the acute phase; isometric exercises progressing to AROM, strengthening , and functional activities. Surgical interventions for severe grade II and grade III sprains involve wiring of the joint, or occasionally the use of screws.

Impingement: occurs with any encroachment of the acromion and/or the coracoacromial ligament on the supraspinatus, the subacromial bursa, and/or the long head of the biceps within the subacromial space. Impingement occurs as a result of deficient shoulder biomechanics; with a number of causative factors:

The key points to treating impingement is recognition, determining the cause, and early intervention. Analysis of biomechanics with correction of joint capsule tightness, muscle imbalances, activity modification including restriction of motion through the painful range, anti-inflammatory modalities, and use of NSAIDS are important first lines of treatment. More intense interventions include injection of corticosteroids, decompressive surgery, or repair of the cuff via suturing of the torn ends.

The therapist must be familiar with the grade of impingement, the interventions of the physician/surgeon, and base treatment strategies on this information.

Tendinitis and Muscle Strains: are frequently seen with the varying grades of impingement. Tendinitis and strains at the shoulder most often have an etiology of repetitive intrinsic loading of the muscle/overuse, which may be associated with over-fatigue or weakening of specific muscles, including the rotator cuff, scapulothoracic muscles, etc. (Hammer, 1991, p. 44).

Supraspinatus tendinitis/strain: The most common sites of involvement are just before the insertion on the greater tuberosity and at the musculotendinous junction. The supraspinatus can be tested for tendinitis/strain by using the "empty can sign," also known as the test for the supraspinatus. Grade III strains can be confirmed by employing the drop arm test. Almost all tears of the rotator cuff, except those due to direct trauma, occur at or near the insertion of the muscle, and are due to overuse: "the cuff wears before it tears" (Reid, 1991, p. 47).

Bicipital tendinitis/strain: often associated with tendinitis of the rotator cuff and at times is cuff tendinitis can be misdiagnosed as biceps tendinitis. True tenosynovitis of the long head of the biceps is invariably found under and just distal to the transverse humeral ligament. It is usually the result of overuse, a direct blow, laxity of the transverse humeral ligament resulting in subluxation of the tendon. Bicipital tendinitis is diagnosed using Speed's test, and pathology of the transverse humeral ligament is diagnosed using Yergason's test.

Treatment of the muscle and tendon strains: consists of ice and various modalities; specific stretching and friction massage of the involved muscle, followed by strengthening. Because the majority of tendinitis is caused by eccentric overload, rehabilitation should be directed toward improving eccentric stress, via progressive eccentric strengthening. The therapist should assess shoulder biomechanics, with the strengthening regime including any weak muscles that contribute to abnormal mechanics. Finally, the person's life roles must be addressed, and exercises that will have transfer to the person's activities should be implemented.

Bursitis: at the shoulder, almost always involves the subacromial bursa. Almost all cases of subacromial bursitis are preceded by tendinitis/tenosynovitis of the rotator cuff. Subacromial bursitis occurs as the result of a weak rotator cuff being unable to effectively oppose upward translation of the deltoid, thus allowing the humerus to translate up into the acromion, effectively "squeezing" the bursa and causing inflammation.

Because tendinitis/strain usually precedes bursitis, they may be present simultaneously and sometimes difficult to differentiate on physical exam. With tendinitis, pain is elicited with resisted tests, but usually not with passive tests. Bursitis may cause pain with resisted tests and is also present with passive tests, especially at the end of range of motion. If bursitis is present, the therapist may have positive active, passive, and resisted tests.

Treatment of subacromial bursitis is the same as for muscle strains and tendinitis.

Adhesive Capsulitis: fibrosis of the joint capsule due to inflammation and limited movement, usually as the result of a preceding pathology, such as muscle strain, tendinitis, bursitis, etc, which may have been preceded by another problem, usually impingement. Adhesive capsulitis is rare in people under the age of 40 and is more common in sedentary individuals.

Adhesive capsulitis is diagnosed via active and passive range of motion testing, with a capsular end-feel being noted at end range, and the presence of a capsular pattern, usually external rotation, abduction, and internal rotation. Treatment strategies include modalities to stretch the capsule, joint mobilization, and functional exercises. The therapist should also work to identify the underlying pathology that precipitated the capsulitis.

Thoracic Outlet Syndrome: is a term used to describe a variety of neurovascular compression syndromes associated with the neurovascular bundle of the brachial plexus (medial trunk, C8-T1) and the subclavian artery and vein. These syndromes become symptomatic due to poor posture and muscle tone.

Signs and symptoms include burning and numbness in the shoulder and ulnar side of the arm, forearm, and hand; decreased sensation, atrophy, and/or weakness of the muscles supplied by the involved nerves; and a diminished radial pulse when certain structures are stressed. The diminished radial pulse, accompanied by numbness and burning of the upper extremity, are used to implicate the structures causing the compression by employing special tests. The following structures associated with the thoracic outlet can cause compression of the neurovascular bundle:

Anterior scalene syndrome: in which the bundle is compressed between the anterior scalene and the middle scalene muscles. Confirmed by the Thoracic Outlet Test for Tight Anterior Scalene / Adson Maneuver: while palpating the radial pulse, the therapist abducts the arm to 45 degrees and extends the shoulder to 45 degrees. The patient is then asked to fully turn his/her head toward the side being tested, extend the cervical spine, and take a deep breath and hold it for 15 to 30 seconds.

Costoclavicular syndrome: the bundle is compressed between the first rib and clavicle. Confirmed by the Thoracic Outlet Test for Costoclavicular Syndrome: while palpating the radial pulse on the side being tested, the therapist abducts the arm to 45 degrees and extends the shoulder to 45 degrees, while applying a downward distraction to the upper extremity as the patient actively retracts and depresses the scapula. The patient holds his/her head in neutral (looks straight ahead) then takes a deep breath and holds it for 15 to 30 seconds.

Pectoralis minor syndrome: the bundle is compressed by a tight pectoralis minor muscle. Confirmed by the Thoracic Outlet Test for Pectoralis Minor Syndrome / Hyperabduction Test: the therapist continuously palpates the radial pulse on the side being tested, then the therapist hyperabducts the upper extremity, placing the patient's hand behind their head, applying over-pressure and holding for 30 - 45 seconds.

Cervical rib syndrome: the presence of a cervical rib compresses the neurovascular bundle. Implicated by a positive Thoracic Outlet Test for a Cervical Rib / Halstead Maneuver: the therapist continuously palpates the radial pulse on the side being tested, then the therapist abducts the arm to 45 degrees, extends the shoulder to 45 degrees, and externally rotates the upper extremity while applying a downward distraction to the arm. The patient is then asked to fully turn his/her head away from the side being tested and extend the cervical spine. Correction of this syndrome almost always requires surgical intervention.

Treatment for Thoracic Outlet syndrome: first and foremost, the therapist must know which anatomic structure is causing compression. From here, it is a matter of correcting the biomechanics/posture of the individual by stretching tight structures and strengthening weak structures. Modification of life roles may be indicated as well.

Fractures of the Shoulder Complex

Stress Fractures in the upper extremity are uncommon. Traumatic fractures on the structures of the shoulder are managed as follows:

Clavicular fractures: are usually due to direct blows sustained from a fall on the point of the shoulder. Most common site is the junction of the middle and outer third of the clavicle. Treatment depends on the amount of displacement of the fracture, with undisplaced/minimally displaced fractures being treated with a sling. Significant displacement/overlapping fragments may require figure of eight bandage to retract the shoulder girdle, minimize the overlap, and allow more anatomic healing. There are few indications for O.R.I.F. of the clavicle (Reid, 1992, p. 986).

Scapular fractures: most fractures are generated by direct blows, with the exception of the glenoid rim fractures, which are usually in association with dislocations. Fractures of the scapula are divided into the following regions:

Fractures of the body: rarely require treatment except for support and immobilization to relieve pain. Displacement of the fracture is uncommon, due to the large number of muscular attachments holding the various regions in place.

Fractures of the neck: treated nonoperatively. If there is significant displacement, or the fracture extends onto the glenoid margin and involves the joint, consideration must be given to glenohumeral stability.

Fractures of the acromion: caused by direct blows to the acromion. For nondisplaced fractures, a sling is worn with early motion performed; for comminuted fractures, surgery to excise or fix the fractured fragment is indicated.

Fractures of the coracoid process: related to avulsions by the tendon of the coracobrachialis or by the pectoralis minor. These fractures heal uneventfully on their own.

Humeral fractures: One of the major concerns with fractures of the humerus is the relation of the axillary nerve proximally and the radial nerve in the middle third as it passes through the spiral groove. The majority of humeral fractures are fixated internally, especially with fractures of the humeral head that are associated with dislocation, and with fractures of the shaft of the humerus. Plates, screws, k-wires, etc. are commonly employed.

Therapy for fractures: the large range of motion that is so necessary at the glenohumeral joint is jeopardized after injury, frequently by the formation of adhesions/capsular fibrosis, therefore it is important to institute motion prior to the maturation of these adhesions as soon as possible. In determining a rehabilitation program for a patient with a fracture that has been fixated, therapists should consider the type of fracture, its severity, the type of fixation used, and the normal biomechanics of the joint. A review of the surgeon's notes and a discussion with the orthopedic surgeon will provide valuable information regarding care and progression of the patient.

Evaluation of the Shoulder

Differential Tests of the Shoulder Include:


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