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9 The Shoulder
Fig. 9.2 In this cutaway view of the shoulder joint, the
humeral head has been removed, allowing visualization of
the interior of the normal glenohumeral anatomy. Notice
the discrete ligaments that constitute the anterior shoulder
capsule, namely the superior (SGHL), middle (MGHL),
and anterior inferior glenohumeral ligaments. In this illustration, the most important anterior restraining structure,
the inferior glenohumeral ligament complex (IGHLC) is
shown to be further subdivided into having anterior (AB)
and posterior (PB) bands and an axillary pouch (AP).
(From Rockwood CA Jr., Matsen FA III eds. The Shoulder.
Vol 1. Philadelphia, PA: Saunders; 1990. Reprinted with
permission)
rotator interval and is extra- articular. It originates from the lateral base of the coracoid, fanning out to envelope the supraspinatus tendon
inserting on the greater tuberosity and the subscapularis tendon inserting on the lesser tuberosity. The CHL is a primary restraint to inferior
translation and external rotation in the adducted
arm. The transverse humeral ligament forms
the apex of the rotator interval and contributes
to the superior soft tissue sling that stabilizes
the long head of the biceps tendon as it passes
through the interval to enter (or exit) the glenohumeral joint.
203
The Long Head oftheBiceps Tendon
The long head of the biceps tendon (LHBT)
remains somewhat enigmatic with respect to its
function in the shoulder girdle but is nonetheless
a potential source of pain and disability. The long
head of the biceps enters/exits the glenohumeral
joint at the rotator interval by way of the bicipital
groove and is an intra-articular structure. The
LHBT originates from the superior glenoid
tubercle and blends with the bers of the superior
labrum. This intimate relationship of the LHBT
with the superior labrum is a signicant source of
morbidity in the throwing athlete.
Although there is conicting data, the long
head of the biceps is thought to be a humeral head
depressor and may contribute to glenohumeral
instability. Potentially more relevant is the theory
of the “peel-back” mechanism of SLAP (superior
labrum anterior posterior) tears. This theory suggests that the LHBT and superior labrum can be
torn from the superior glenoid in the late cocking
position of a baseball pitch as the LHBT becomes
taut and “peels back” the superior labrum off the
glenoid rim. Whether or not this theory is correct,
SLAP tears can be a signicant problem in the
throwing athlete. Tendinitis of the LHBT is also a
common source of morbidity in the shoulder and
is often a component of the impingement syndrome.
The Rotator Cu
The rotator cuff consists of four muscle-tendon
units including the subscapularis, supraspinatus,
infraspinatus, and teres minor. These muscles
originate on the scapula and insert onto the tuberosities of the proximal humerus. The subscapularis originates on the anterior surface of the
scapula and inserts onto the lesser tuberosity. The
remaining rotator cuff muscles originate from the
posterior surface of the scapula and insert along
the greater tuberosity. The roles of the rotator
cuff are to keep the humeral head centered in the
glenoid fossa throughout the range of shoulder
motion and to contribute to the rotation and elevation of the extremity. As such, the rotator cuff
204
E. Michaelson and B. Wiesel
is the primary dynamic stabilizer of the glenohumeral joint. Traumatic and overuse injuries to the
rotator cuff are the most common problems in the
shoulder girdle.
The Subacromial Space
The subacromial space is a potential space
beneath the acromion and above the rotator cuff.
The subacromial bursa outlines the subacromial
space and provides frictionless gliding of the
rotator cuff beneath the acromion and coracoacromial arch. Bony osteophytes on the undersurface of the anterior acromion have been
postulated to narrow the subacromial space, irritate the subacromial bursa, and contribute to
rotator cuff tears.
Fig. 9.3 In this anterior
view, note the
acromioclavicular joint
surrounded by the
capsule
(acromioclavicular
ligament), in addition to
the supporting
coracoclavicular
ligaments, the conoid
and trapezoid. (From
Rockwood CA Jr.,
Matsen FA III eds. The
Shoulder. Vol 1.
Philadelphia, PA:
Saunders; 1990.
Reprinted with
permission)
Coracohumeral ligament
Coracoid process
Opening of subscapular bursa
The Acromioclavicular Joint
The acromioclavicular (AC) joint is a true diarthrodial joint containing a brocartilaginous disc.
The AC joint helps link the appendicular skeleton
with the axial skeleton through the clavicle.
Because there is little intrinsic bony stability to the
AC joint, a number of ligaments and other soft tissues serve to stabilize this articulation (Fig.9.3).
The superior AC ligament is the most important
horizontal stabilizer. The coracoclavicular (CC)
ligaments, consisting of the conoid ligament
(medial) and the trapezoid ligament (lateral), provide the primary restraint to vertical displacement
of the clavicle. A signicant amount of rotation
occurs in the clavicle throughout the arc of elevation of the upper extremity. Approximately 10% of
this rotation occurs at the acromioclavicular joint.
Clavicle
Conoid lig.
Trapezoid lig.
Acromioclavicular ligament
Coracoclavicular
ligament
Acromion
Coracoacromial
ligament
Capsule
Intertubercular
synovial sheath
Humerus
Scapula
9 The Shoulder
205
The Sternoclavicular Joint
The sternoclavicular (SC) joint is the only bony
connection the upper appendicular skeleton has
to the axial skeleton and has the least bony stability of any major joint. The majority of clavicular rotation occurs at the sternoclavicular
joint, but less than 50% of the bulbous, medial
clavicle is in contact with the shallow, sternal
articular fossa. Thus, the soft tissues provide
stability to the sternoclavicular joint. The ligamentous anatomy of the SC joint includes the
intra-articular disk ligament, the costoclavicular
ligament, the interclavicular ligament, and the
capsular ligament. Of these, the posterior sternoclavicular joint capsule has been shown to be
the most important structure for preventing both
anterior and posterior displacement of the
medial clavicle.
The Scapulothoracic Articulation
The scapulothoracic articulation includes the
scapula, posterior thorax, and interposed bursae
which provide frictionless motion between the
scapula and posterior thorax. The scapulothoracic articulation provides a signicant percentage of motion to the shoulder girdle. Specically,
the glenohumeral joint and scapulothoracic
articulation function in a synchronous fashion to
provide full forward elevation of the upper
extremity in a 2:1 ratio. The scapular stabilizer
muscles include the trapezius, levator scapulae,
rhomboids, latissimus dorsi, and serratus anterior. Dysfunction of scapulothoracic motion,
seen clinically as scapular winging, may be a
result of nerve injury or muscle dysfunction.
Damage to the spinal accessory nerve results in
trapezius dysfunction and lateral scapular winging. Long thoracic nerve injury leads to serratus
anterior dysfunction and medial scapular winging. Pain and loss of motion in the glenohumeral
joint can lead to overuse and fatigue of the scapular stabilizer muscles resulting in pseudo winging of the scapula.
The Brachial Plexus
The brachial plexus is comprised of the ventral
rami of cervical roots C5, C6, C7, C8, and ventral
thoracic root T1. With the exception of the spinal
accessory nerve (XI) which innervates the trapezius, all of the muscles contributing to the function
of the shoulder girdle and upper extremity are
innervated by nerves originating from the brachial
plexus. The brachial plexus includes ve nerve
roots, three trunks (superior, middle, and inferior),
six divisions (three anterior, three posterior), three
cords (lateral, medial, and posterior), and six terminal branches (musculocutaneous, ulnar, medial
cord branch to median nerve, lateral cord branch to
median nerve, axillary, and radial). With the exception of the divisions, nerves originate from each
level of the brachial plexus to innervate muscles of
the shoulder girdle. Brachial plexus injuries are
relatively common with traumatic shoulder girdle
injuries such as proximal humerus fractures, glenohumeral dislocations, and fracture/dislocations.
Clinical Examination
oftheShoulder Girdle
The history of present illness is critical in the
evaluation of shoulder girdle pathology and
should be used to develop a reasonable differential diagnosis based on the patient’s story, age,
and the epidemiology of shoulder pathology. For
example, a high school athlete with activityrelated shoulder pain is more likely to have instability or labral pathology than a rotator cuff tear.
Conversely, a 65-year-old who has shoulder pain
with activities of daily living is more likely to
have rotator cuff disease than a labral tear or
instability. The physical examination is used to
narrow the differential diagnosis and make the
denitive diagnosis. Most of the time, an accurate diagnosis can be made using only the history
and physical examination. Indiscriminate use of
imaging studies and additional testing is not recommended. Prior to ordering additional studies,
the examiner must have a clear understanding of
206
E. Michaelson and B. Wiesel
how the study will contribute to the evaluation
and treatment of the patient.
History
Patients with shoulder pathology most often
complain of pain, stiffness, instability, and weakness. When pain is the chief complaint, the examiner must characterize the pain, with particular
attention to location. Pain from the glenohumeral
joint and its surrounding soft tissues typically is
localized to the anterosuperior aspect of the
shoulder. Localization of the pain to the deltoid
insertion in the arm is common in rotator cuff or
subacromial pathology. Pain emanating from the
neck or to the posterior scapular region is frequently due to cervical spine disease. Pain and
crepitation in the periscapular region, however,
may be related to scapulothoracic bursitis.
The timing and frequency of shoulder pain must
also be given careful consideration. Activity-related
pain can provide valuable clues as to the underlying
diagnosis. Pain with overhead activities of daily living is common in rotator cuff pathology. Pain with
sporting activities such as swimming, throwing, or
serving is often related to the labrum or glenohumeral instability. In overhead athletes it is important
to determine the phase of the throwing motion during which the pain occurs. Night pain is often
reported with shoulder girdle pathology, especially
in the setting of rotator cuff tears. Patients will often
report the inability to sleep on the affected side. Rest
pain is uncommon but may occur with severe
arthropathy or radicular pain from the cervical
spine. If rest pain is the predominant complaint, the
examiner should consider infection or malignancy
as a possible source of pain.
The relationship of pain to injury is important
to establish. Pain that begins with a traumatic
event such as a fall on an outstretched hand,
direct blow to the shoulder, or shoulder dislocation may represent signicant damage to the rotator cuff, ligaments, or bony structures. Pain that
begins days or weeks after a seemingly innocuous event such as shoveling snow, trimming
hedges, or painting may represent tendonitis or
early capsulitis. Pain that begins more insidiously
or over time is more likely to be related to degenerative lesions of the shoulder girdle such as rotator cuff tears or osteoarthritis.
Complaints of shoulder instability are relatively common. The patient may describe the
shoulder “slipping out of place” or “getting
stuck” in extreme positions. It is important to
establish whether a frank shoulder dislocation
was ever documented. True traumatic shoulder
dislocations are the result of signicant trauma
and require a manipulative reduction. Unfortunately, subsequent dislocations may occur with
less trauma. Patients who have shoulders which
“slip out of place” and “slide back in” on their
own are more likely to have multidirectional
instability as opposed to traumatic instability.
Weakness or loss of shoulder function is also a
frequent complaint. In the absence of pain, a neurologic origin of the deteriorating function should
be considered. Insidious onset of pain with deteriorating function may represent a degenerative
condition of the shoulder or adhesive capsulitis.
A careful review of systems is important to
document as there are a number of disease processes remote from the shoulder girdle that can
result in shoulder pain. Cervical spine pathology,
cardiac disease, gallbladder disease, and lung
disease (pancoast tumor) can present with shoulder pain. A history of cancer is also important to
document as metastatic cancer can present with
shoulder pain and lesions in the shoulder girdle.
Functional Assessment
In addition to establishing the history of present
illness, it is imperative to establish the functional
status of the patient. Important patient factors to
note include the handedness (right, left, or ambidextrous) of the patient, the vocation of the patient,
extracurricular/sporting activities enjoyed by the
patient, assistive devices used for ambulation, and,
most importantly, the expectations of the patient
regarding their shoulder problem. Understanding
the patient’s functional demands and expectations
allows the clinician to prescribe appropriate treatment regimens and to provide reasonable expectations for functional recovery.
9 The Shoulder
207
Inspection
The physical examination begins with inspection of
the shoulder girdle. The region must be adequately
exposed for the examination. The inspection begins
with assessment of symmetry between the involved
and uninvolved shoulder girdles. Gross deformities
such as distal clavicle prominence in an AC separation, prior surgical incisions, skin discoloration, or
open wounds are readily appreciated. A more subtle
nding is muscle atrophy which may be the result
of disuse or injury. Patients with longstanding rotator cuff tears will often have atrophy of the supraand infraspinatus fossae resulting in prominence of
the spine of the scapula. Traumatic injuries can produce subtle deformities. In the setting of an anterior
dislocation, the anterior aspect of the shoulder may
appear “full” and the posterior aspect may lose its
normal contour making the posterior acromion
appear more prominent. Inspection should continue
through the entire exam as some deformities such as
scapular winging may only be revealed during provocative testing.
Palpation
The primary importance of palpation is to localize the source of pain. Palpation of bony prominences and supercial joints yields the most
information. In the absence of trauma, palpation
includes the SC joint, AC joint, the greater and
lesser tuberosities, and the bicipital groove.
Tenderness on palpation at any of these sites can
be a valuable clue in making a diagnosis. When
the presenting complaint is neck or periscapular
pain, palpation of the posterior elements of the
cervical spine and bony elements of the scapula
is warranted. In the setting of trauma, palpation
of all bony structures and areas of deformity is
critical to localize the zone of injury.
Range ofMotion
The evaluation of range of motion is straightforward. The examiner directs the motions and
observes for symmetry. The standard motions
include forward elevation, external rotation,
internal rotation, and abduction. Forward elevation occurs in the plane of the scapula and is a
combination of scapulothoracic and glenohumeral motion. When testing range of motion,
scapulothoracic motion and other compensating
mechanisms must be observed and controlled for
accurate measurements. Loss of glenohumeral
motion can lead to scapulothoracic substitution
and scapular winging. External rotation is evaluated with the arms at the side to prevent scapulothoracic contribution to rotation. Internal rotation
is evaluated by having the patient place his or her
hands as high as possible along the midline of the
back. Internal rotation is graded by the approximate vertebral level the patient is able to reach.
Assessment of abduction, including internal and
external rotation in abduction, is critical for
unmasking subtle losses of motion. Throwing
athletes often lose some internal rotation in
abduction while gaining external rotation in
abduction in their throwing arm. There is no net
loss of motion, only a resetting of the range of
motion relative to the non-throwing shoulder.
When loss of active motion is identied, the
examiner must assess the passive range of motion.
If there is loss of active and passive motion, there
is likely a soft tissue contracture or a physical
block to motion (dislocation, loose body, or osteophyte). In the absence of trauma, loss of both
active and passive motion usually represents adhesive capsulitis (frozen shoulder) or glenohumeral
arthritis. If there is loss of active motion with preserved passive motion, the examiner must consider
tendon (rotator cuff) rupture or, potentially, nerve
damage. When examining the rotator cuff muscles, the examiner must appreciate lag signs.
A lag sign can be documented when the patient
has a loss of active motion with preservation of
passive motion. The examiner positions the shoulder at the end range of full passive motion and
instructs the patient to maintain the position. If the
patient is unable to maintain the position and the
extremity falls away, the patient is considered to
have a positive lag sign. The horn blower’s sign is
the lag sign for the abducted, externally rotated
position and is suggestive of a massive rotator cuff
tear involving the posterior cuff.
208
E. Michaelson and B. Wiesel
Strength Assessment
The relative strength of muscle groups can be
assessed during the physical examination. In
order to assess strength, the examiner manually
resists the patient’s active motion in a dened
plane such as abduction, adduction, and internal
or external rotation. Asymmetric weakness on the
involved side can provide additional diagnostic
information. Weakness or paralysis of the scapular stabilizer muscles can be assessed by having
the patient perform pushups against a wall.
Scapular winging can be elicited using this
technique.
Neurologic Examination
In the absence of trauma or brachial plexopathies, most neurologic lesions about the shoulder
involve a peripheral nerve. Common peripheral
neuropathies in the shoulder girdle include the
suprascapular, spinal accessory, and long thoracic nerves. Although these conditions can be
painful, many patients report dysfunction or cosmetic deformity as the presenting complaint.
These lesions are appreciated during the inspection, range of motion and strength testing of the
shoulder girdle. Suprascapular neuropathy can
occur at the level of the suprascapular notch or
proximal and involve both the supra- and infraspinatus tendons resulting in prominence of the
scapular spine and weakness of forward elevation
and external rotation. Suprascapular nerve lesions
at the level of the spinoglenoid notch involve
only the infraspinatus muscle resulting in atrophy
of the infraspinatus fossa and weakness of external rotation. Compression in this area is often the
result of a paralabral cyst associated with a labral
tear and is common in overhead athletes. Spinal
accessory nerve injury is often iatrogenic from a
posterior cervical node biopsy or a radical neck
dissection for malignancy. Injury to the spinal
accessory nerve (cranial nerve XI) results in trapezius dysfunction and lateral scapular winging.
Long thoracic nerve injury is thought to be secondary to traction or contusion and affects the
serratus anterior muscle resulting in medial scapular winging. Medial or lateral refers to the direc-
tion toward which the inferior border of the
scapula is directed. Nerve lesions in the shoulder
girdle should be further evaluated with electromyography (EMG) and nerve conduction testing.
The majority of these nerve lesions (except iatrogenic laceration) recover without surgical
intervention.
Special Tests andSigns
There are many special tests or maneuvers that
have been described to evaluate individual structures or reveal specic pathology. Physical examination of the shoulder can be challenging, as
exam ndings may overlap multiple diagnoses,
patients may have multiple coexisting pathologies, and shoulder disorders may have variable
presentations. The examiner should elect to perform specic maneuvers and evaluate the results
of these tests in the context of the patient demographics, history, and complaints. A few of these
tests and signs are reviewed below.
Rotator Cu
The most commonly used tests attempt to recreate the pain that occurs with rotator cuff impingement under the coracoacromial (CA) arch by
rotating the greater tuberosity under the acromion. The painful arc sign occurs when the
patient experiences pain while elevating the
upper extremity from 70° to 120°. The Neer
impingement sign is positive when shoulder pain
is reproduced as the upper extremity is passively
elevated in the scapular plane with the scapula
stabilized (Fig. 9.4). Unrestricted passive range
of motion is required specically for a positive
Neer impingement sign. Hawkins’s impingement
sign is tested by passively internally rotating the
humerus when the arm is at 90° of forward exion with the elbow exed. A positive test is
dened as shoulder pain with this maneuver. The
drop arm test is performed by placing the upper
extremity at shoulder level (90°) in the scapular
plane with the thumb pointing downward. The
test is considered positive when the patient is
unable to maintain the extremity in this position
and is indicative of superior rotator cuff
pathology.
9 The Shoulder
Fig. 9.4 Impingement of the rotator cuff is demonstrated
by passively elevating the shoulder against the xed scapula. Pain suggests the possibility of mechanical compression of the rotator cuff against the anterior inferior
acromion, a process known as impingement. (From
DeLee JC, Drez D Jr. Orthopaedic Sports Medicine:
Principles and Practice. Vol 1. Philadelphia, PA:
Saunders; 1994. Reprinted with permission)
Multiple tests have been described to evaluate
the subscapularis. The lift-off test is performed
by having the patient place his or her hands
behind the back with the arm internally rotated
and the elbow exed. The patient is then asked to
lift the hands off the back without extending the
elbows. If the patient is unable to perform the liftoff, the test is considered positive and indicative
of subscapularis insufciency. For patients who
are unable to reach behind their back, the belly
press test can be used to evaluate the subscapularis. The belly press test is performed by having
the patient place his or her hands on the abdomen
and, while pressing the hands to the abdomen,
bringing the elbows anterior to the coronal plane
of the body. Inability to perform the belly press
maneuver is a positive test. The bear-hug test is
performed by having the patient place the pathologic arm in 90° of forward exion with the hand
209
resting on the contralateral AC joint. The examiner then attempts to lift the hand off the contralateral shoulder by applying an external rotation
force to the forearm. Inability of the patient to
actively maintain hand position on the contralateral shoulder is positive and indicative of subscapularis pathology.
Biceps Tendon (Long Head
andSuperior Labrum)
Speed’s test is used to evaluate the long head of
the biceps tendon. The test is performed by having the patient maintain forward elevation of the
upper extremity at shoulder height against resistance with the elbow extended and the forearm
supinated. The test is considered positive when
pain is produced in the area of the bicipital groove
with the maneuver. Yergason’s test is performed
by having the patient actively supinate the forearm against resistance with the arm at the side
and the elbow in 90° of exion. A positive nding
for biceps pathology is seen with pain localized
to the bicipital groove.
The active-compression test, or O’Brien’s
test, is used to evaluate the superior labralbiceps tendon complex. The test is performed in
two steps. The upper extremity is brought to
shoulder height in forward exion with the forearm fully pronated (thumb down) and adducted
approximately 15°. The patient resists the examiner’s downward pressure from this position. If
this maneuver elicits pain in the shoulder, the
test is repeated with the forearm supinated. If
the pain is reduced or absent with the second
maneuver, the test is considered positive. A positive test indicates that the biceps tendon-superior labral complex is torn or detached from the
superior glenoid. The examiner should be aware
that pain localized to the top of the shoulder
during active-compression testing is likely
related to the AC joint rather than the superior
labrum. Cross-body adduction testing, positive
with pain when the shoulder is exed to 90° and
the arm passively adducted across the body, is
indicative of AC joint pathology and can be used
to differentiate AC joint pain from labral pathology in the setting of an uncertain activecompression nding.
210
E. Michaelson and B. Wiesel
Shoulder Instability
A number of tests have been described to evaluate shoulder instability. All of the following tests
can be performed with the patient supine on the
examining table. The apprehension test is performed with the shoulder abducted to 90° and
externally rotated to 90° in the coronal plane of
the body. From this position, the examiner continues to externally rotate the shoulder. If the
patient experiences apprehension (fear of the
shoulder dislocating), the test is considered positive. If the patient has a positive apprehension
test, the examiner can reduce the subluxated
humeral head by applying a posterior directed
force against the proximal humerus, thereby
reducing the humeral head. If the apprehension
is relieved, the relocation test is positive. The
examiner can then release the proximal humerus.
If apprehension recurs with release of the posterior directed force, the release test is positive.
The posterior apprehension test employs a similar concept, but with the arm in a position at risk
for posterior instability. The shoulder and elbow
are exed 90° with the arm in adduction and
internal rotation. The examiner stabilizes the
scapula with one hand while applying a posteriorly directed axial load through the elbow.
Posterior apprehension is positive when pain or
apprehension is elicited.
The load-and-shift test is used to assess the
direction and degree of shoulder laxity. The
examiner uses one hand to apply a longitudinal
load to the humerus directed toward the glenohumeral joint. This hand is located at the elbow
with the elbow exed. The other hand is used to
apply a perpendicular force to the proximal
humeral shaft in an attempt to shift (subluxate or
dislocate) the humeral head relative to the glenoid. The test is performed while maintaining the
upper extremity in the coronal plane of the body.
The degree of abduction/rotation and the direction of the applied force can be varied to evaluate
the various glenohumeral ligaments. The test is
graded by the examiner who determines through
tactile sense whether the humeral head translates
to the glenoid rim (1+); over the glenoid rim but
spontaneously reduces (2+); or over the rim
requiring manual reduction (3+). This test is
often more useful in the anesthetized patient due
to guarding in the awake patient.
Imaging Studies andOther
Diagnostic Tests
The use of routine imaging studies and tests to
evaluate the shoulder girdle for diagnostic purposes is not recommended. At the conclusion of
the history and physical examination, the examiner should have a reasonable diagnosis.
Additional tests or studies are used to answer
specic questions. If the clinical diagnosis is frozen shoulder but the examiner is concerned that
the patient has glenohumeral arthritis, it is reasonable to order radiographs to rule out osteoarthritis since the natural history and treatment of
osteoarthritis and adhesive capsulitis are dissimilar. If the clinical diagnosis is rotator cuff
impingement or tendonitis, there is no reason to
obtain further studies initially as they will not
change the recommended course of treatment.
Radiographs
The standard shoulder series includes an anteroposterior (AP) X-ray in the plane of the scapula;
a Y-outlet view; and an axillary view. This series
of X-rays is mandatory in the evaluation of shoulder girdle trauma. Unfortunately, the axillary
view is often not obtained, yet it is the most sensitive for documenting shoulder dislocations. The
Velpeau view may replace the axillary view if the
patient is not able to participate in the axillary
view due to pain or range of motion restrictions.
AP views with the humerus internally and externally rotated may be used to critically evaluate
greater tuberosity fractures or calcic tendinitis.
The scapula is approximately 30° oblique to the
coronal plane of the body; therefore, in order to
obtain a true AP view of the glenohumeral joint,
the X-ray beam must be obliquely oriented to the
coronal plane of the body (Fig.9.5). The AP view
is useful for evaluating the clavicle, AC joint, glenohumeral joint space, glenoid, scapular body,
proximal humeral shaft, surgical neck, and
greater tuberosity. The Y-outlet view is useful for
evaluating the scapular spine, scapular body, cor-
ROUTINE A-P SHOULDER
9 The Shoulder
211
Post. Glenoid rim
Ant. Glenoid rim
a
45°
TRUE A-P SHOULDER
Ant. & Post.
Glenoid rims
superimposed
b
cd
Fig. 9.5 These illustrations and X-rays demonstrated the
importance of obtaining a “true” anteroposterior (AP) perspective of the glenohumeral joint. In X-ray (a), note that
the AP view is actually one of the thoraxes, yielding an
X-ray which shows overlap of the glenohumeral joint.
When the beam is angled, however, as in (b), a “true” AP
acoid, shape of the acromion, and spur formation
in the CA ligament. The axillary view is critical
in evaluating glenohumeral joint congruence.
Anterior or posterior dislocations are best seen
on the axillary view.
Magnetic Resonance Imaging
The magnetic resonance imaging (MRI) scan is
commonly employed to evaluate the soft tissues
of the shoulder girdle and is considered the gold
standard for evaluating the rotator cuff tendons.
Subacromial uid, tendon inammation, and
rotator cuff tears are all visible with MR imaging.
MRI scans can be performed with an arthrogram
view of the glenohumeral joint is obtained. Note the differences in appearance in these views in (c) (AP view of
the thorax) and (d) (true AP view of the glenohumeral
joint). (From Rockwood CA Jr., Matsen FA III eds. The
Shoulder. Vol 1. Philadelphia, PA: Saunders; 1990.
Reprinted with permission)
(intra-articular contrast dye) to better delineate
intra-articular structures such as labral tears and
articular-sided partial rotator cuff tears. Standard
MRI views of the shoulder include coronal
oblique, sagittal oblique, and axial cuts. The coronal and sagittal views are termed oblique
because they are obtained in the plane of the
scapula which is oblique to the coronal and sagittal planes of the body. Although the MRI scan is
a powerful tool in the evaluation of shoulder
problems, it is a very sensitive test. Positive ndings, therefore, may correlate poorly with a
patient’s clinical presentation. For example, MRI
scans obtained on patients with normal, pain-free
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E. Michaelson and B. Wiesel
shoulders have documented a greater than 50%
incidence of rotator cuff tears in patients over the
age of 60. It is therefore important to treat the
patient and not the MRI scan.
Computerized Tomography
Computerized tomography (CT) scans are useful
in the evaluation of bone abnormalities. In the
setting of complex or comminuted shoulder girdle fractures, CT scanning with or without image
reconstruction is a powerful tool for clinical decision making and/or preoperative planning. CT
scans are useful in the evaluation of shoulder
instability, providing the best characterization of
humeral impaction fractures, known as HillSachs lesions, and both posterior and anterior
glenoid bone loss. CT scans are also valuable in
assessing bone deciencies such as glenoid wear
and are commonly obtained prior to shoulder
arthroplasty in any patients with signicant glenoid deformity.
Electrodiagnostic Testing
Electromyography (EMG) and nerve conduction
velocity (NCV) testing are commonly used to
evaluate neurologic lesions of the shoulder girdle. EMG testing involves placing small needle
electrodes into the muscles to record resting
potentials and ring patterns. NCV testing is
used to document the speed with which an
impulse is conducted along a peripheral nerve.
Abnormalities such as a conduction block may
indicate severe nerve injury. Electrodiagnostic
testing is useful in documenting both the presence and recovery of peripheral nerve lesions as
well as identifying the anatomic origin of nerve
compression.
Evaluation andTreatment
ofCommon Shoulder Problems
The majority of common shoulder girdle problems result from degenerative changes, overuse,
or traumatic injury. Atraumatic shoulder pain is
common and includes rotator cuff disease,
arthropathy, adhesive capsulitis, calcic tendinitis, and multidirectional instability. Most
atraumatic shoulder pain is initially treated with
activity modication, anti-inammatory medication, and physical therapy. Treatment regimens may vary depending on the specic
diagnosis. Calcic tendinitis, for example,
responds well to subacromial corticosteroid
injections. The physical therapy prescription
may also vary depending on the diagnosis.
Patients with adhesive capsulitis require stretching exercises, in contrast to patients with rotator
cuff tendonitis who are treated with rotator cuff
strengthening exercises. Surgical treatment in
the atraumatic population is generally reserved
for those patients who fail to respond to nonoperative treatment regimens. A basic algorithm
for the evaluation of atraumatic shoulder pain is
provided in Fig.9.6.
Traumatic injuries to the shoulder girdle are
common and include both soft tissue and bony
injury. Treatment is individualized based on the
age of the patient, functional status of the patient,
and the severity of the injury. Depending on the
injury, nonoperative or operative treatment may
be appropriate. Common traumatic injuries to the
shoulder girdle include shoulder dislocations, AC
joint injuries, clavicle fractures, and proximal
humerus fractures and are reviewed in the skeletal trauma chapter. Contrary to popular belief,
traumatic rotator cuff tears are relatively uncommon although they should always be considered
in the setting of weakness following a traumatic
injury to the shoulder.
Rotator Cu Disease
Degenerative and overuse injuries of the rotator
cuff (RC) are common sources of shoulder pain
and disability. Anterosuperior shoulder pain emanating from the rotator cuff under the coracoacromial arch has historically been called
impingement syndrome, encompassing a spectrum of pathology in the subacromial region
including subacromial bursitis, RC tendinopathy,
partial-thickness RC tears, and full-thickness RC
tears. Abnormalities in scapulothoracic movement, also known as scapular dyskinesia, may
contribute to symptoms of impingement. Partial