Anatomy, Kinesiology, Pathomechanics, and Diagnosis

of Shoulder Impingement Symptomp

Tirza Z. Tamin

Department of Physical Medicine and Rehabilitation, Dr. Cipto Mangunkusumo General Hospital,

Faculty of MeAdicine, University of Indonesia, Jakarta, Indonesia

tirzaediva.tamin@gmail.com

Keywords : Shoulder Impingement, Shoulder Problems, Early Diagnosis

Abstract : Musculoskeletal complaints with the highest prevalence of patients coming to the hospital one of which is

shoulder pain. Based on several studies the current prevalence of complaints of shoulder pain ranges from 7-

36% of the population. The most common cause of complaints of shoulder pain coming to the Orthopedic

clinic or Medical Rehabilitation is a patient with Shoulder Impingement Syndrome (SIS). Patients with SIS

will experience functional limitations making it difficult to do work as usual and difficult to lift weights

above the head. SIS that occurs continuously will become a functional disability and decreased quality of

life. Initial treatment in this case is given non-operatively, making rehabilitation the first choice as therapy.

1 INTRODUCTION

Shoulder pain is a common presenting complaint

from patients of all ages in daily clinical practice,

affecting approximately one-third of individuals

during their lifetime (Dong W et al, 2015). Such

pain may lead to the impairment of shoulder joint

function and to severe reduction in quality of life.

Shoulder impingement syndrome, which is defined

as the compression of the rotator cuff and the

subacromial bursa, is considered to be one of the

most common causes of shoulder pain and may be

cited as a contributing factor to shoulder pain in up

to 65% of cases (Garving et al, 2017). Shoulder

impingement is a clinical syndrome in which soft

tissues become painfully entrapped in the area of the

shoulder joint. Shoulder impingement has been

defined as compression and mechanical abrasion of

the rotator cuff structures as they pass beneath the

coracoacromial arch during elevation of the arm

(Dong W et al, 2015). In literature shoulder

impingement syndrome (SIS) is reported to be a

contributing factor between 48% and 65% of all

painful shoulder conditions (Burbank et al, 2008).

Different kinds of SIS are defined in literature

depending on the structures involved: subacromial

impingement syndrome (SAI), internal impingement

(IIM), and Sub-coracoid impingement (SC)

(Garving et al, 2017).

Charles Neer described subacromial

impingement as the compression and abrasion of

the bursal side of the rotator cuff beneath the

anterior acromion, and developed the anterior

acromioplasty as a treatment (Neer, 1983).

External impingement is now understood as a

much broader category than that described by

Neer, and could include compression or abrasion

of the cuff tendons or tendon of the long head of

the biceps brachii beneath any aspect of the

coracoacromial arc (Neer, 1983). The

coracoacromial arch includes not just the acromial

undersurface, but also the coracoacromial

ligament, and the undersurface of the

acromioclavicular (AC) joint (Garving et al,

2017).

2 DISCUSSION

2.1 Joints

The main function of the joints of the shoulder girdle

is to move the arm and hand into almost any position

in relation to the body. As a consequence, the

304

Tamin, T.

Anatomy, Kinesiology, Pathomechanics, and Diagnosis of Shoulder Impingement Symptomp.

DOI: 10.5220/0009090003040315

In Proceedings of the 11th National Congress and the 18th Annual Scientiﬁc Meeting of Indonesian Physical Medicine and Rehabilitation Association (KONAS XI and PIT XVIII PERDOSRI

2019), pages 304-315

ISBN: 978-989-758-409-1

shoulder joint is highly mobile, where stability takes

second place to mobility, as is evident from the

shape of the osseous structures: a large humeral head

lying on an almost flat scapular surface. Stability is

provided mainly by ligaments, tendons and muscles;

the bones and capsule are of secondary importance.

The function of the shoulder girdle requires an

optimal and integrated motion of several joints. In

fact, five ‘joints’ of importance to ‘shoulder’

function can be distinguished:

1. The glenohumeral joint

2. The acromioclavicular joint

3. The sternoclavicular joint

4. The subacromial joint or subacromial gliding

mechanism: the space between the

coracoacromial roof and the humeral head,

including both tubercles. This is the location of

the deep portion of the subdeltoid bursa

5. The scapulothoracic gliding mechanism: this

functional joint is formed by the anterior aspect

of the scapula gliding on the posterior thoracic

wall. Optimal mobility also requires an intact

neurological and muscular system.

2.1.1 Glenohumeral joint

Figure 3: The glenohumeral joint capsule and ligament:

1. Superior; 2. Medial, 3. Inferior (glenohumeral

ligaments).

The glenohumeral joint is a ball-and-socket between

humeral head and glenoid fossa. There is a

remarkable geometrical relationship between

glenoid and head which is responsible for the

considerable mobility of the joint but is also an

important predisposing factor to glenohumeral

instability. First, the large spherical head of the

humerus articulates against the small shallow

glenoid fossa of the scapula (only 25–30% of the

humeral head is covered by the glenoid surface).

Second, the bony surfaces of the joint are largely

incongruent (flat glenoid and round humerus).

However, the congruence is greatly restored by the

difference in cartilage thickness: glenoid cartilage is

found to be the thickest at the periphery and thinnest

centrally, whereas humeral articular cartilage is

thickest centrally and thinnest peripherally. This

leads to a uniform contact between humeral head

and glenoid surface throughout shoulder motion

(Rockwood et al, 2009).

The labrum is a fibrous structure that forms a

ring around the periphery of the glenoid. It further

contributes to stability of the joint by increasing the

depth of the glenoid socket, enlarging the surface

area and acting as a load-bearing structure for the

humeral head. The synovial membrane of the joint

capsule is mainly attached to the labrum, covering

its inner surface, and at the anatomical neck of the

humerus. The fibrous portion of the capsule is very

lax and has several recesses, depending on the

position of the arm. Very often adhesions form here.

The joint capsule is large, loose and redundant

allowing full and free range of motion of the

shoulder.

The rotator cuff and labrum are the

shoulder structures most vulnerable to

throwing injuries (Lin DJ et al, 2018).

Figure 2: Shoulder (glenohumeral) joint: 1.

Labrum, 2. Glenoid cartilage, 3. Shoulder

capsule.

Figure 1: A global view of five joints of

the shoulder girdle: 1. Glenohumeral

joint; 2. Acromioclavicular joint; 3.

Sternoclavicular joint; 4. Subacromial

joint or subacromial gliding mechanism;

5. Scapulothoracic gliding mechanism.

Anatomy, Kinesiology, Pathomechanics, and Diagnosis of Shoulder Impingement Symptomp

305

Figure 4: The glenohumeral joint.

the anterior portion of the capsule three local

reinforcements are present: the superior, medial and

inferior glenohumeral ligaments. These contribute,

together with the subscapularis, supraspinatus,

infraspinatus and teres minor muscles, to the

stability of the joint. By virtue of the blending of

their tendons with the glenohumeral capsule and

ligaments, selective contraction of the cuff muscles

can adjust the tension in these structures, producing

‘dynamic’ ligaments (Rockowood et al, 2009).

2.1.2 Acromioclavicular joint

The acromioclavicular joint is the only articulation

between the clavicle and the scapula. The

anteroposterior stability of the acromioclavicular

joint is controlled by the acromioclavicular

ligaments and the vertical stability is controlled by

coracoclavicular ligaments (conoid and trapezoid)

(Rockwood et al, 2009).

2.1.3 Sternoclavicular joint

Its the medial end of clavicle lies in contact with the

superolateral angle of the sternal manubrium and

with the medial part of the cartilage of the first rib to

form the sternoclavicular joint. In both the vertical

and anteroposterior dimensions, the clavicular

portion is larger than the opposing manubrium and

extends superiorly and posteriorly relative to the

sternum. The prominence of the clavicle enables its

palpation. The sternoclavicular joint is mobile along

all axes and almost every movement of the scapula

and the arm is associated with some movement at

this joint (Rockwood et al, 2009).

2.2 Muscles

The primary muscle group that supports the shoulder

joint is the rotator cuff muscles. The four rotator cuff

muscles are supraspinatus, infraspinatus, teres minor,

and subscapularis. Together the rotator cuff muscles

form a musculotendinous cuff as they insert on the

proximal humerus.

The rotator cuff muscles attach to the proximal

humerus anteriorly at the greater tuberosity. The

rotator cuff muscles provide considerable structural

support to the glenohumeral joint and keep the

humeral head in a firm position by articulating with

the scapula within the glenoid cavity. The muscles

of the chest also provide structural support to the

shoulder joint (Eovaldi et al, 2018).

2.2.1 Supraspinatus Muscle

The supraspinatus muscle functions by abduction of

the humerus up to 30 degrees, as well as to stabilize

the glenohumeral joint (Burbank et al, 2008).

Approximately 70% of the muscle fibers attach

to the intramuscular tendon, whereas 30% attach

directly to the extra muscular tendon. This muscle is

categorized as a circumpennate muscle (Eovaldi et al,

2018).

The supraspinatus is part of the force couple to

stabilize the glenohumeral joint by compression and

initializes elevation. Elevation in case of

supraspinatus paralysis requires more deltoid force,

Figure 6: The sternoclavicular joint.

Figure 5: Acromioclavicular joint;

S:Superior, I:Inferior, L:Lateral, M:Middle.

KONAS XI and PIT XVIII PERDOSRI 2019 - The 11th National Congress and The 18th Annual Scientiﬁc Meeting of Indonesian Physical

Medicine and Rehabilitation Association

306

but the other rotator cuff muscles are still able to

stabilize the humeral head sufficiently for full range

of motion. The suprascapular nerve (C4-6) supplies

innervation (Reyes et al, 1978).

2.2.2 Infraspinatus Muscle

The infraspinatus muscle functions by externally

rotating the humerus and doing horizontal abduction

(Reyes et al, 1978).

2.2.3 Teres Minor Muscle

The Teres minor acts to externally rotate the

humerus and assists with abduction of the humerus.

Similar to the infraspinatus, this is a circumpennate

muscle with a single intramuscular tendon located in

the center of the muscle belly. The teres minor

muscle acts as stabilizer of the glenohumeral joint

by resisting posterior and superior translation and

generates 45% of the total external rotation force.

2.2.4 Subscapularis Muscle

As the only component of the anterior rotator cuff, it

stabilizes actively the glenohumeral joint by

resisting anterior and inferior translation and acts as

a strong internal rotator. It is considered to be a

passive stabilizer too, because of the dense collagen

structure of its tendon and its fusion with the middle

and inferior glenohumeral ligament (Eovaldi et al,

2018).

2.2.5 Trapezius Muscle

The only muscle which acts to depress the shoulder

is the lower trapezius, which is assisted by gravity in

the upright position. The function of the trapezius

muscle is both elevation and depression of the

shoulder depending on whether the upper or lower

muscle fibers are activated. When the entire

trapezius muscle contracts the fibers are

geometrically opposed, and the forces are balanced

resulting in no movement of the shoulder (Eovaldi et

al, 2017).

Figure 8: The Infraspinatus and Teres

Minor Muscle.

Figure 7. The Supraspinatus Muscle

Figure 9: The Subcapsularis Muscle

Anatomy, Kinesiology, Pathomechanics, and Diagnosis of Shoulder Impingement Symptomp

307

Figure 10: The Trapezius Muscle

2.2.6 Deltoid Muscle

The deltoid muscle overlies the shoulder

superficially and functions to abduct the humerus.

The deltoid muscle has three origins; the body of the

clavicle, the spine of the scapula, and the acromion.

The deltoid muscle has three origins; the body of the

clavicle, the spine of the scapula, and the acromion.

The deltoid muscle has its insertion on the deltoid

tuberosity of the humerus. The short head of the

biceps brachii originates from the coracoid process,

and the long head originates from the supraglenoid

tubercle, passing through the intertubercular groove

of the proximal humerus. The biceps brachii is not a

shoulder muscle but does originate from the

shoulder. Paralysis of the deltoid results mainly in

50% loss of abduction strength. The axillary nerve

(C4-5) innervates the deltoid (Lynn, 2000).

2.3 Etiology of SIS

Internal impingement was ﬁrst described as a

condition noted in overhead athletes, identiﬁed in

part due to poor outcomes of acromioplasty in this

population.

Multiple theories exist as to the primary

etiology of shoulder impingement, including

anatomic abnormalities of the coracoacromial arch

or humeral head“tension overload,” ischemia, or

degeneration of the rotator cuff tendons; and

shoulder kinematic abnormalities. Regardless of the

initial etiology, inflammation in the suprahumeral

space, inhibition of the rotator cuff muscles, damage

to the rotator cuff tendons, and altered kinematics

are believed to exacerbate the condition.

Impingement is thought to be due to inadequate

space for clearance of the rotator cuff tendons as the

arm is elevated. Therefore, factors that further

minimize this space are believed to be detrimental to

the condition (Ludewig and Cook, 2000)

There are some structures that could contribute

to its onset, such as the shape of the acromion, the

coracoacromial ligament, the superior aspect of the

glenoid fossa, hypermobility and instability of the

glenohumeral joint, capsular retractions and rotator

cuff tendinopathy (Lewis et al, 2005). Rotator cuff

problems are thought to account for nearly one third

of physician visits for shoulder pain complaints

(Ludewig and Cook, 2000). The vast majority of

people with impingement syndrome who are

younger than 60 years of age relate their symptoms

to occupational or athletic activities that involve

frequent overhead use of the arm. Epidemiologic

investigations have revealed a high prevalence

(16%–40%) of shoulder complaints consistent with

impingement in certain occupations, including

assembly-line workers, welders, steelworkers, and

construction workers. Frequent or sustained shoulder

elevation at or above 60 degrees in any plane during

occupational tasks has been identified as a risk

factor for the development of shoulder tendinitis or

nonspecific shoulder pain. Evidence relating

occupational exposure of frequent or sustained

shoulder elevation to shoulder musculoskeletal

symptoms is strongest for combined exposure to

multiple physical factors, such as holding a tool

while working overhead.

A number of impingement categories have

been identiﬁed including subacromial

impingement or “external impingement”; internal

impingement, which can be further divided into

anterior or posterior; and coracoid impingement.

Figure 11: The Deltoid Muscle.

KONAS XI and PIT XVIII PERDOSRI 2019 - The 11th National Congress and The 18th Annual Scientiﬁc Meeting of Indonesian Physical

Medicine and Rehabilitation Association

308

All categories of impingement are potential

mechanisms for the development or progression

of rotator cuff disease, or long head biceps

tendinopathy. Physical exam ﬁndings consistent

with impingement can also be associated with

labral tears in internal impingement (Budoff, 2003)

or develop secondary to instability or as a delayed

consequence of adhesive capsulitis. There are

multiple mechanisms by which impingement may

occur, including excess or reduced motion and

abnormal patterns of motion at particular portions

of the range of motion (Micahener et al, 2003). In

addition, anatomic abnormalities of the humerus

or acromion have been implicated in impingement.

It should be noted that rotator cuff disease can

develop without impingement, through tensile

overload or intrinsic tissue degeneration.

Regardless of the initial precipitating factor,

however, impingement, abnormal shoulder

motions, and associated rotator cuff disease often

are found in the presence of partial or full

thickness rotator cuff tears. In other words, even if

rotator cuff disease or tearing did not initiate from

impingement or abnormal motion, impingement

and abnormal motion are likely to contribute to

disease progression (Manske et al, 2014).

The subacromial impingement syndrome has

both primary and secondary forms. Primary

impingement is due to structural changes that

mechanically narrow the subacromial space; these

include bony narrowing on the cranial side (outlet

impingement), bony malposition after a fracture

of the greater tubercle, or an increase in the

volume of the subacromial soft tissues – due, e.g.,

to subacromial bursitis or calcific tendinitis – on

the caudal side (non-outlet impingement).

Secondary impingement results from a functional

disturbance of centering of the humeral head,

such as muscular imbalance, leading to an

abnormal displacement of the center of rotation in

elevation and thereby to soft tissue entrapment

(Garving et al, 2017).

2.4 Stages of SIS

Neer graded SIS into 3 different stages. In stage I,

the typical characteristics are reversible lesions with

edema and hemorrhage; most patients younger than

25 years are in this category. In stage II, chronic

inflammation or repeated episodes of impingement

lead to histomorphological changes, such a s

fibrosis and thickening of the supraspinatus, the long

biceps tendon, and subacromial bursae. Patients in

this stage are usually between 25 and 40 years of age.

In stage III, in patients more than 40 years of age,

tears of the rotator cuff, rupture of the biceps tendon,

and bony changes may be observed, accompanied by

significant tendon degeneration following a long

history of refractory tendinitis.

2.5 Normal Motion of Shoulder

During normal motion, the scapula will upwardly

rotate and posteriorly tilt on the thorax during

elevation of the arm in ﬂexion, abduction,

scapular plane abduction, or unrestricted overhead

reaching (Ludewig and Barman, 2011).

Throughout this manuscript, elevation will be

used to refer the raising of the arm overhead in

any of these planes. Scapulothoracic internal or

external rotation is less consistent during arm

elevation, differing in pattern depending on what

plane the arm is elevated in, and depending on

what portion of the elevation range of motion is

considered (Ludewig and Reynolds, 2009). The

scapula must adjust in the transverse plane for the

intended plane of elevation. For ﬂexion, the

scapula will internally rotate somewhat early in

the motion, whereas for coronal plane abduction,

it will externally rotate at the initiation of the

motion. Based on the limited end range data

available, it appears some external rotation of the

scapula will occur near end range for each of

these planes of elevation (Ludewig and Braman,

2011).

Recent investigations have added new

knowledge on how SC and AC joint motions

contribute to overall ST motion. The primary

clavicular motion occurring at the SC joint

during

active arm elevation in any plane

except extension is 30

○

posterior long axis

rotation.

Secondarily, the clavicle will retract

w15

○

at the SC joint during elevation, even with

ﬂexion. However, the clavicle also “adjusts” in

the transverse plane (less retraction with ﬂexion,

more with abduction) similarly to the changes in

scapular internal rotation with ﬂexion versus

abduction (Ludewig and Reynolds, 2009). Finally,

a small amount of clavicular

elevation will occur

at the

SC joint with humeral elevation in any

plane. Concurrent with clavicular motion relative

to the thorax, measurable motion of the scapula

relative to the clavicle is also occurring at the AC

joint as the humerus is elevated in any plane.

Primary AC joint motions include upward rotation

and posterior tilt of the scapula relative to the

clavicle. Secondarily the scapula will internally

rotate relative to the clavicle at the AC joint, even

Anatomy, Kinesiology, Pathomechanics, and Diagnosis of Shoulder Impingement Symptomp

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while abducting the arm (Ludewig and Braman,

2011).

Overall ST motion occurs either through

motion of the clavicle relative to the thorax,

motion of the scapula relative to the clavicle, or

some combination of both. During normal arm

elevation in any plane, both clavicular (SC) and

scapular (AC) motions described above are

contributing to the ﬁnal position of the scapula on

the thorax. However, the non-parallel alignment

of the axes of rotation of the SC and AC joints

makes their contributions to ST motion

challenging to visualize (Teece et al, 2008). The

AC joint axes are aligned consistently with how

the axes are described for the scapula on the

thorax, such that if the scapula upwardly rotates,

posteriorly tilts or internally rotates relative to the

clavicle, there is a

1:1 “coupling” with ST

motion. In other words, 5

○

of scapular

upward

rotation relative to the clavicle would contribute

to 5

○

of ST upward rotation. In order to

understand the coupling of clavicular motion to

ST motion, it is helpful to visualize an axis of

rotation embedded along the long axis of the

clavicle, and another embedded in the scapula

from the root of the scapular spine to the AC joint.

In a superior transverse plane view, ﬁrst imagine a

hypothetical situation where the clavicle and

scapular axes are parallel. In such a hypothetical

alignment, if the clavicle were elevated about its

anteriorly directed axis 9

○

relative to the

thorax,

the scapula would upwardly rotate 9

○

on the

thorax,

assuming no motion of the scapula

relative to the clavicle at the AC joint. If the

clavicle rotated posteriorly about its long axis 30

○

relative to the thorax, the scapula would

posteriorly tilt 30

○

relative to the thorax, and if

the clavicle retracted 9

○

relative to the thorax, the

scapula would externally rotate 9

○

relative to the

thorax (Teece et al, 2008). Now consider an

alternative hypothetical situation where the

scapula is internally rotated 90

○

relative to the

clavicle, such that the described axes in the

transverse plane are at a 90

○

angle (Ludewig

aand Braman, 2011). In such a hypothetical

alignment, if the clavicle were elevated about its

anteriorly directed axis 9

○

relative to the thorax,

the scapula would anteriorly tilt 9

○

on the thorax.

If the clavicle rotated posteriorly about its long

axis 30

○

relative to the thorax, the scapula would

upwardly rotate 30

○

on the thorax, and if the

clavicle retracted 9

○

relative to the thorax, the

scapula would externally rotate 9

○

on the thorax

(Teece et al, 2008).

In addition to the coupling of clavicle

motion to ST motion, during arm elevation in

any plane, the scapula relative to the clavicle is

also moving at the AC joint. These AC joint

motions may increase or decrease the overall

ST joint motion depending on whether they

complement or offset the SC joint coupled

scapular motions. So, in the example above for

scapular plane abduction to

120

○

relative to the

thorax, the 20

○

ST upward rotation coupled with

clavicle posterior rotation on the thorax, and 3

○

ST upward rotation coupled with clavicle

elevation on the thorax would be

complemented by an average of 11

○

scapular upward rotation

relative to the clavicle

across the same increment of scapular plane

abduction. The end result would be 34

○

of ST

upward rotation. For ST tilting, the 10

○

posterior

tilting coupled

with clavicle posterior rotation on

the thorax would be reduced by 6

○

tilting coupled with clavicle elevation on the

thorax as

described above. Subsequently, the

clavicle overall contribution to ST posterior tilting

would only be 4

○

However, the scapula relative to the clavicle

is tilting posteriorly during that scapular plane

abduction motion on average 16

○

, to result in

overall ST motion of 20

○

. Finally the 9

○

of ST

external rotation coupled with clavicle

retraction on the thorax is offset by an

average of 6

○

scapula internal rotation relative to

the clavicle, resulting in 3

○

of ST external

rotation. Note that ﬁnal resulting

scapular

upward rotation motion and position on the

thorax is produced by complementary motion

of the clavicle relative to the thorax and scapula

relative to the clavicle. ST tilting is produced

almost exclusively by scapular motion relative to

the clavicle as the clavicle elevation and

posterior rotation motions at the SC joint are

offsetting. ST external rotation is minimal due to

offsetting motions of clavicle retraction relative

to the thorax and scapular internal rotation

relative to the clavicle (Ludewig and Braman,

2011).

KONAS XI and PIT XVIII PERDOSRI 2019 - The 11th National Congress and The 18th Annual Scientiﬁc Meeting of Indonesian Physical

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2.6 Abnormal Shoulder Motion in

Impingement

Rrecent review article identiﬁed scapular motion

abnormalities in subjects with impingement or

rotator cuff disease. The most frequent ﬁndings

have been reduced ST posterior tilting, reduced

ST upward rotation, increased ST internal

rotation, or increased clavicular elevation

relative to the thorax (Ludewig and Reynolds,

2009). These movement alterations are believed

to increase proximity of the rotator cuff tendons

to the coracoacromial arch or glenoid rim

(Ludewig and Braman, 2011).

Additionally, increased humeral head superior

or anterior translation has been found in subjects

with impingement

(Ludewig and Braman, 2011)

These directions of humeral head motion are

believed to reduce the subacromial space and

increase impingement risk. Biomechanical

evidence also supports the idea of glenohumeral

internal rotation contributing to sub- acromial

impingement beneath the anterior structures

(Ludewig and Braman, 2011)

Figure 12: Anatomical overview of the shoulder (left, above), showing the mechanism of subacromial impingement with

painful entrapment of soft tissues (arrows, right, above) on elevation of the arm, due to pathological contact of the humeral

head with the roof of the shoulder joint, particularly the anterolateral portion of the acromion (below).

Acromial shapes as classified by Bigliani and Morrison: type I (flat), type II (curved), type III (hooked).

Recent work also demonstrates how angles of

humeral elevation which minimize the

subacromial space may differ from angles of

humeral elevation where the rotator cuff soft

tissues are at greatest risk. The subacromial space

is typically described as minimized at 90

○

humeral elevation in all planes. However,

the

portion of the humerus in closest contact at that

point in the range of motion of abduction is

actually the lateral aspect of the greater tuberosity,

which has no rotator cuff soft tissue. The rotator

cuff tendons are actually in closest proximity to

the undersurface of the acromion near 45

○

humeral abduction relative to the thorax. By

angles past 60

○

humeral abduction, the

attachment sites or footprints of the cuff tendons

on the greater tuberosity have rotated past the

lateral acromial undersurface.

Patients may still

have a painful arc of motion near 90

○

of humeral

elevation in any plane, since this is where rotator

cuff muscle forces are highest. However, pain at

or above 90

○

of humeral elevation relative to the

thorax is unlikely a direct result of a compressive

subacromial impingement of the rotator cuff

Anatomy, Kinesiology, Pathomechanics, and Diagnosis of Shoulder Impingement Symptomp

311

tendons. Alternatively, proximity of the

undersurface of the cuff tendons to the superior

glenoid rim increases at higher arc

(Ludewig

and Braman, 2011)

. These same factors can

inﬂuence humeral motions. In summary, there is

some evidence of increased upper trapezius

activation and reduced serratus anterior activation

in the same subjects who have demonstrated

reduced ST posterior tilting, increased internal

rotation, and reduced upward rotation. There is

also evidence of increased ST anterior tilting and

internal rotation in subjects with a relatively short

resting length of the pectoralis minor

(Ludewig

and Braman, 2011)

Glenohumeral internal rotation deﬁcit and

experimentally induced posterior capsule

tightness have also been shown to increase ST

anterior tilting and humeral anterior translations

relative to the glenoid, respectively. Slouched

sitting, thoracic kyphosis, and increased age have

also been related to increased ST anterior tilting

and internal rotation and reduced ST upward

rotation

(Ludewig and Braman, 2011)

Although not experimentally demonstrated,

other factors including reduced rotator cuff

activation and pectoralis major tightness can be

biomechanically theorized to impact ST or

glenohumeral kinematics in ways that are

believed to increase impingement risk. Each of

these factors provides additional insight in

planning treatment intervention approaches

targeted to speciﬁc movement deviations.

2.7 Clinical Presentation

The patient should be asked about the nature,

duration, and dynamics of the pain and about any

precipitating trauma (perhaps trivial trauma) or

stress, as well as about analgesic use. Patients

often report painful elevation and depression of

the arm between 70 ° und 120 °, pain on forced

movement above the head, and pain when lying

on the affected shoulder. The physical

examination consists of inspection, palpation,

and passive and active range-of-motion testing of

the shoulder, with attention to scapular

dyskinesia and hyperlaxity or instability of the

glenohumeral joint. Strength is tested in

comparison to the opposite side. In sub- acromial

impingement syndrome, weakness mainly affects

abduction or external rotation. Testing includes

the active and passive range of motion, iso-

metric contraction testing for the selective

determination of strength in internal and external

rotation and in abduction, and additional

impingement tests. The sensitivity and

specificity of such tests is low individually, but,

taken together, they are indispensable for the

differential diagnosis. Examining techniques are

summarized in Table 1.

Although impingement symptoms may arise

following trauma, the pain more typically develops

insidiously over a period of weeks to months. The

pain is typically localized to the anterolateral

acromion and frequently radiates to the lateral mid-

humerus. Patients usually complain of pain at night,

exacerbated by lying on the involved shoulder, or

sleeping with the arm overhead. Normal daily

activities such as combing one’s hair or reaching up

into a cupboard become painful, and a general loss

of strength may be noted. Onset of shoulder pain and

weakness following a fall in an individual over 40

years of age should raise concern for a complete tear

of the rotator cuff (Garving et al, 2017).

2.7.1 The tests

A thorough examination of the neck and shoulder is

critical to properly diagnosing SIS. Strength testing

of the upper extremities as well as neck and shoulder

ranges of motion should be carefully assessed. In

SIS, active and passive shoulder range of motion is

typically normal. The muscles of the rotator cuff are

Table 1: Examination for Shoulder Impingement

Syndrome.

Hawkins

test

Positive when pain arises on maximal

internal rotation of the arm in 90° of

anteversion with the elbow flexed. This

narrows the subacromial space

between the greater tubercle and the

coracoacromial ligament, causing

pain.

Neersign

One hand fixes the scapula while the

other elevates and internally rotates the

arm. This causes painful contact of the

greater tubercle with the roof of the

shoulder joint.

Jobe test

Both of the patient’s arms are held in

90° of abduction, 45° of flexion, and

internal rotation. The patient tries to

elevate the arms further against the

examiner’s marked resistance.

Painful

arch

Pain on abduction, with extended

elbow, in the scapular plane between

60° and 120° indicates pathology in the

subacromial space.

KONAS XI and PIT XVIII PERDOSRI 2019 - The 11th National Congress and The 18th Annual Scientiﬁc Meeting of Indonesian Physical

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best isolated with 3 separate maneuvers. To isolate

the subscapularis, the patient places their hand

behind the back and attempts to push away the

examiner’s hand, a maneuver called the lift-off test.

Next, with the arms at the sides and the elbows

flexed, the examiner resists the patient in external

rotation of the shoulder. Next, to isolate the

supraspinatus, which may be painful with SIS, the

patient abducts the arms to 90°, forward flexes to 30°,

and internally rotates each humerus so that the

thumbs are pointed to the floor. A downward force

is then applied to the forearms as the patient resists

(Garving et al, 2017).

Two provocative examination techniques are

highly sensitive but not very specific for diagnosing

SIS. Neer’s sign elicits pain with maximum passive

shoulder elevation and internal rotation while the

scapula is stabilized (Dong W et al, 2015). Hawkins

sign is pain with passive forward elevation to 90°

and maximum internal rotation (Garving et al, 2017).

These 2 tests have a negative predictive value of

greater than 90% when combined (Burbank et al,

2008). Marked rotator cuff weakness with positive

impingement signs may indicate a complete cuff

rupture. The Neer impingement test involves

injecting the subacromial space with 10 mL of local

anesthetic and observing an amelioration of pain

with these provocative tests (Garving et al, 2017).

2.8 Diagnostic And Evaluation

Clinical history-taking and a thorough physical

examination are the basis of the diagnostic

assessment. The diagnostic sensitivity of

physical examination is 90%. Imaging studies

(initially, plain x-rays) are indispensable for

differential diagnosis and for the exclusion of

calcific tendinitis or arthritic changes. If the

patient has had a circumscribed functional

limitation or persistent pain for 6 weeks or more

despite the usually adequate analgesia and

physical therapy, further imaging studies and

referral to a specialist are recommended

(Garving

et al, 2017).

2.8.1 Differential Diagnosis

Narrowing the etiology of shoulder pain can be

difficult as a number of conditions often coexist in

older individuals. The etiology of adhesive capsulitis

is unknown, although thought to be inflammatory in

nature. The disease is more commonly encountered

among women in their 50s and 60s. It is 5 times

more likely to occur in patients with diabetes

mellitus

and has been associated with

hypothyroidism. Adhesive capsulitis often presents

with unremitting shoulder pain at rest, and early

stages of adhesive capsulitis may present much like

impingement syndrome. Later, patients will develop

progressive loss of motion, with loss of internal

rotation an early sign of the motion loss. Patients

with adhesive capsulitis will be limited in both

active and passive ranges of motion, particularly in

contrast to SIS, where passive motion is unrestricted

(Garving et al, 2017).

Cervical radiculopathy may present with unilateral

shoulder pain. This can be particularly difficult to sort

out in older patients who may have both rotator cuff

pathology and cervical spine osteoarthritis. The patient

with shoulder pain of a cervical origin may have pain

and spasm in the trapezius muscles and a limited neck

range of motion. They may also experience pain,

numbness, or paresthesia radiating to the arm and hand.

Symptoms may be provoked by hyperextension and

lateral rotation of the neck (Spurling’s maneuver). A

key historical detail may be that pain is alleviated

when the forearm is rested above the head (Garving et

al, 2017).

Degenerative changes within the acromioclavicular

(AC) joint and osteolysis of the distal clavicle are often

found in individuals with a history of heavy labor or

weightlifting but may occur in anyone. The pain may

be present over the AC joint itself or be referred to the

upper shoulder and neck. Sleeping on the affected side

and overhead movements exacerbate the symptoms.

Physical examination typically confirms the diagnosis

with marked tenderness over the AC joint and pain

with compression of the joint through adduction of the

elevated arm. Osteoarthritis of the glenohumeral joint

presents with a painful diminished range of motion.

Arthritic changes in either joint are apparent on

radiographs (Garving et al, 2017).

3 CONCLUSION

The natural course of SIS is poorly described, but

evidence suggests that the condition is not self-

limiting (Garving et al, 2017). The initial

management of shoulder impingement has

traditionally included medical rehabilitation program

(therapeutic exercise and modalities), nonsteroidal

anti-inflammatory drugs (NSAIDs), and

corticosteroid injection. Medical rehabilitation

program (therapeutic exercise and modalities) is

frequently implemented to lessen pain and improve

function in SIS. In addition to medical rehabilitation

Anatomy, Kinesiology, Pathomechanics, and Diagnosis of Shoulder Impingement Symptomp

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programs (therapeutic exercise and modalities) and

medications, activity and workplace modifications

must be discussed. Patients should attempt to

discontinue overhead activities until symptoms

diminish. It may be helpful to discuss “living within

a window” in which they consciously attempt to keep

their hands within an area in front of their body

during activity. The “window” should be from chest

to waist and 2 to 3 feet wide, allowing the patient to

avoid reaching over- head, away from the body, or

behind the back, all of which will exacerbate their

symptoms (Garving et al, 2017).

Bearing in mind that the literature offers few

truly well-conducted trials regarding the

management of SIS, we present an algorithm of our

recommended management of SIS based upon a

synthesis of the best available literature. Note that an

MRI is not recommended until at least a 6-week

therapeutic trial has been implemented unless a

complete rupture is suspected (Garving et al, 2017).

Figure 13: Treatment algorithm for subacromial impingement syndrome. SIS = subacromial

impingement syndrome; NSAID = nonsteroidal anti-inflammatory drug; PT = physical therapy.

KONAS XI and PIT XVIII PERDOSRI 2019 - The 11th National Congress and The 18th Annual Scientiﬁc Meeting of Indonesian Physical

Medicine and Rehabilitation Association

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