MR Imaging of
Rotator Cuff Injury:
What the Clinician
Needs to Know1
FOR TEST 4
After reading this
article and taking
the test, the reader
will be able to:
? Discuss the impli-
cations of the mor-
phologic features and
extent of rotator cuff
tears for glenohu-
meral joint mechan-
ics, treatment, and
? Identify injuries to
that may accompany
rotator cuff tears and
discuss their implica-
tions for treatment
? Describe the value
of imaging and evalu-
ating the rotator cuff
Yoav Morag, MD●Jon A. Jacobson, MD●Bruce Miller, MD●Michel
De Maeseneer, MD, PhD●Gandikota Girish, MD●David Jamadar, MD
The rotator cuff muscles generate torque forces to move the humerus
while acting in concord to produce balanced compressive forces to sta-
bilize the glenohumeral joint. Thus, rotator cuff tears are often associ-
ated with loss of shoulder strength and stability, which are crucial for
optimal shoulder function. The dimensions and extent of rotator cuff
tears, the condition of the involved tendon, tear morphologic features,
involvement of the subscapularis and infraspinatus tendons or of con-
tiguous structures (eg, rotator interval, long head of the biceps brachii
tendon, specific cuff tendons), and evidence of muscle atrophy may all
have implications for rotator cuff treatment and prognosis. Magnetic
resonance imaging can demonstrate the extent and configuration of
rotator cuff abnormalities, suggest mechanical imbalance within the
cuff, and document abnormalities of the cuff muscles and adjacent
structures. A thorough understanding of the anatomy and function of
the rotator cuff and of the consequences of rotator cuff disorders is es-
sential for optimal treatment planning and prognostic accuracy. Identi-
fying the disorder, understanding the potential clinical consequences,
and reporting all relevant findings at rotator cuff imaging are also es-
RadioGraphics 2006; 26:1045–1065●Published online 10.1148/rg.264055087●Content Codes:
1From the Departments of Radiology (Y.M., J.A.J., M.D.M., G.G., D.J.) and Orthopedic Surgery (B.M.), University of Michigan Medical Center,
1500 E Medical Center Dr, TC-B1-132G, Ann Arbor, MI 48109-0326. Presented as an education exhibit at the 2004 RSNA Annual Meeting. Re-
ceived April 11, 2005; revision requested June 30 and received August 19; accepted August 26. All authors have no financial relationships to disclose.
Address correspondence to Y.M. (e-mail: firstname.lastname@example.org).
test at http://
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The anatomic status of the rotator cuff tendons is
one of a number of factors that must be taken into
account when planning the treatment of rotator
cuff injury. Diagnostic imaging of the rotator cuff
provides valuable information with regard to the
dimensions of full-thickness and partial-thickness
tears, tendon retraction or thinning, tear shape,
anatomic extent of tears and involvement of spe-
cific tendons or structures, pathologic changes
involving the rotator cuff muscles, and morpho-
logic features of the coracoacromial arch. This
information is important because it may affect
therapeutic decision making, surgical planning,
and postsurgical prognosis.
In this article, we review the function and anat-
omy of the rotator cuff and the mechanism of cuff
tears. In addition, we discuss and illustrate the
treatment of rotator cuff tears and the role of di-
agnostic imaging—particularly magnetic reso-
nance (MR) imaging—in the diagnosis and treat-
ment of these tears.
Rotator Cuff Function
The rotator cuff is important in shoulder move-
ment; initiation of shoulder abduction relies on
the function and integrity of the supraspinatus
muscle and tendon and other rotator cuff tendons
(1). Without supraspinatus function, a significant
increase in the force exerted by the middle seg-
ment of the deltoid muscle is needed to initiate
abduction. Large rotator cuff tears extending be-
yond the supraspinatus tendon are associated
with loss of the ability to abduct the glenohumeral
joint beyond 25°. The rotator cuff also has an im-
portant role in rotation of the shoulder. The in-
fraspinatus muscle is the main external rotator in
the shoulder, whereas the subscapularis muscle is
an important internal rotator (2).
Glenohumeral joint stability is provided by a
delicate balance between static stabilizers (eg,
glenohumeral joint labroligamentous complex,
joint capsule, osseous structures) and dynamic
stabilizers, including the rotator cuff muscles (3).
The rotator cuff provides substantial anterior dy-
namic stability to the glenohumeral joint in the
end range as well as the midrange of motion (4).
The infraspinatus, subscapularis, and latissimus
dorsi muscles act as stabilizers during flexion, the
subscapularis muscle acts as a stabilizer during
external rotation, and the subscapularis and su-
praspinatus muscles work together as stabilizers
during extension (2). The subscapularis, infraspi-
natus, and teres minor muscles act in unison to
firmly center the humeral head within the glenoid
fossa (1). The infraspinatus muscle also has a role
as a humeral head depressor (5). Clinicians sug-
gest strengthening the rotator cuff muscles to
compensate for laxity of the joint capsule and
Proper shoulder function depends on a large
range of motion without compromising stability,
which entails precise balance between shoulder
stabilizers and shoulder mobilizers. In a thrower,
in whom extraordinary forces are applied to the
shoulder complex, this need for precise balance is
dubbed the “thrower’s paradox.” The thrower’s
shoulder must be lax enough to allow external
rotation but stable enough to prevent subluxation
(6). Proper function of the rotator cuff muscles,
which help both mobilize and stabilize the shoul-
der, is essential for optimal shoulder function.
Rotator Cuff Anatomy
The rotator cuff consists of the supraspinatus,
infraspinatus, subscapularis, and teres minor
muscles and tendons. At the distal aspect of the
rotator cuff, the supraspinatus and infraspinatus
tendons splay out and interdigitate, forming a
common continuous insertion on the middle facet
of the humeral greater tuberosity (Fig 1) (7–9).
To a lesser extent, the supraspinatus and sub-
scapularis tendons demonstrate contiguity, with
interwoven fibers from these two tendons envel-
oping the biceps tendon. With this arrangement
of fibers, loads from the contraction of one mus-
cle cuff are not isolated to that muscle insertion
but are dispersed to adjacent tendons (10). Thus,
the rotator cuff is a functional-anatomic unit
rather than four unrelated tendons, and injury to
one component may have an influence on other
regions of the rotator cuff (11).
Rotator Cuff Injury
The pathogenesis of rotator cuff injury is contro-
versial. Neer (12) suggested an “extrinsic” theory:
Hypertrophic changes of the acromion cause im-
pingement of the subacromial-subdeltoid bursa
and the rotator cuff. Association between rotator
cuff tears and osteophytes from the acromiocla-
RG f Volume 26
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vicular joint and the type 3 (hooked) acromion
lends additional support to the extrinsic impinge-
ment hypothesis (13,14).
According to the “intrinsic” (intratendinous)
theory, the pathogenesis of rotator cuff tears is
tendon degeneration. Degenerative partial-thick-
ness tears of the rotator cuff tendons may allow
superior migration of the humeral head. This mi-
gration will in turn cause abrasion of the rotator
cuff tendons against the undersurface of the acro-
mion, thereby leading to full-thickness tears
Possible secondary causes of rotator cuff dis-
ease include overuse and fatigue of scapular stabi-
lizers, adhesive capsulitis, and glenohumeral in-
stability, which may lead to impingement (17).
Intrinsic muscle contractile tension overload has
also been cited as a potential cause of rotator cuff
Rotator cuff tears have also been described
following acute trauma. Anterior dislocation of
the shoulder may be associated with rotator cuff
tears, which, if undetected, may be the cause of
recurrent anterior instability (19). Posttraumatic
subscapularis tendon tears may be isolated or as-
sociated with injuries to the long head of the bi-
ceps brachii tendon (20). In older individuals,
tendon rupture may occur after acute trauma to
rotator cuff tendons with underlying chronic de-
generative changes (21).
Rotator Cuff Tears
The goal in the treatment of rotator cuff injury is
pain relief with return of shoulder strength and
range of motion. Rotator cuff tears may initially
be treated conservatively. Surgical treatment may
be considered in symptomatic rotator cuff tears
and in subacromial impingement that has not re-
sponded to nonsurgical treatment (22–24).
Asymptomatic rotator cuff tears are relatively
common, especially in older individuals, but
whether surgical intervention is needed to avoid
future complications in these cases is not clear
(25–29). Thus, the anatomic status of the rotator
cuff is only one of a number of factors that must
be taken into account when considering surgical
treatment. Other factors include the patient’s
subjective symptoms, expectations, and func-
tional requirements; shoulder function as objec-
tively evaluated; and chronicity of the injury (23).
The potential benefits of repair of rotator cuff
tears have been well established. The assumption
that restoration of cuff integrity will restore func-
tion has been proved in cadaveric studies (30).
Clinical studies have shown improved function
and strength, decreased pain, and improved per-
formance of daily activities after rotator cuff
rated T2-weighted MR images (repetition time msec/echo time msec ? 3000/60) (a obtained medial to b)
show overlap between the distal supraspinatus tendon (SST) (green) and the distal infraspinatus tendon (IST)
Overlap between the distal supraspinatus and infraspinatus tendons. Consecutive sagittal fat-satu-
RG f Volume 26
● Number 4Morag et al1047
repair (31,32). Even patients with recurrent tear
experienced improvement compared with their
preoperative condition, although to a lesser extent
than patients who had undergone successful re-
Surgical repair of full-thickness rotator cuff
tears has also been shown to be superior to sub-
acromial decompression in terms of long-term
(3–7-year) outcome and function (34,35).
Massive rotator cuff tears that are not treated
may progress to rotator cuff arthropathy, which is
characterized by progressive weakening of the
subchondral bone with impaction of the humeral
head against the acromion and acromioclavicular
joint, leading to bone erosions and, ultimately,
humeral head collapse (Fig 2) (36,37).
The apparent advantages of surgical repair are
offset somewhat by the fact that even successful
surgery will only partially restore shoulder func-
tion, by the high risk of tear recurrence, and by a
relatively lengthy rehabilitation process (31).
Thus, when rotator cuff tears are diagnosed, the
orthopedic surgeon must weigh the therapeutic
options carefully before making a treatment rec-
ommendation. Imaging can supply important
information that may assist in decision making
and surgical planning.
rotator cuff tear with only subscapularis tendon (SSC) fibers remaining. A ? acromion, D ? del-
toid muscle, H ? humeral head. (b) Coronal oblique T1-weighted MR image (620/8) shows supe-
rior subluxation of the humeral head (H) abutting the acromion (A). G ? glenoid fossa. (c) Ra-
diograph obtained in a different patient also shows superior subluxation of the humeral head abut-
ting the acromion (cf b). (d) Coronal oblique T1-weighted MR image (620/8) obtained in a third
patient shows subchondral bone marrow edema caused by impaction of the humeral head (H)
against the acromion (arrow), a condition that may progress to collapse.
Rotator cuff arthropathy. (a) Sagittal T1-weighted MR image (620/8) shows a massive
RG f Volume 26
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59. Lo IK, Burkhart SS. Transtendon arthroscopic
repair of partial-thickness, articular surface tears
of the rotator cuff. Arthroscopy 2004;20(2):214–
60. Weber SC. Arthroscopic debridement and acro-
mioplasty versus mini-open repair in the treat-
ment of significant partial-thickness rotator cuff
tears. Arthroscopy 1999;15(2):126–131.
61. Zhang L, Makhsous M, Lin F, Koh J, Nuber
GW, Levin SD. Biomechanical analysis of partial
thickness tear of the supraspinatus tendon under
static and dynamic loading. Presented at the 4th
annual meeting of the International Shoulder
Group, Cleveland, Ohio, June 17–18, 2002.
62. Reilly P, Amis AA, Wallace AL, Emery RJ. Su-
praspinatus tears: propagation and strain alter-
ation. J Shoulder Elbow Surg 2003;12(2):134–
63. Ellman H, Kay SP. Arthroscopic subacromial
decompression for chronic impingement: two-
to five-year results. J Bone Joint Surg Br 1991;
64. Snyder SJ, Pachelli AF, Del Pizzo W, Friedman
MJ, Ferkel RD, Pattee G. Partial thickness rota-
tor cuff tears: results of arthroscopic treatment.
65. McConville OR, Iannotti JP. Partial-thickness
tears of the rotator cuff: evaluation and manage-
ment. J Am Acad Orthop Surg 1999;7(1):32–43.
66. Weber SC. Arthroscopic debridement and acro-
mioplasty versus mini-open repair in the manage-
ment of significant partial-thickness tears of the
rotator cuff. Orthop Clin North Am 1997;28(1):
67. Park JY, Yoo MJ, Kim MH. Comparison of sur-
gical outcome between bursal and articular par-
tial thickness rotator cuff tears. Orthopedics
68. Burkhart SS. Reconciling the paradox of rotator
cuff repair versus debridement: a unified biome-
chanical rationale for the treatment of rotator cuff
tears. Arthroscopy 1994;10(1):4–19.
69. Lehman RC, Perry CR. Arthroscopic surgery for
partial rotator cuff tears. Arthroscopy 2003;
70. Cordasco FA, Backer M, Craig EV, Klein D,
Warren RF. The partial-thickness rotator cuff
tear: is acromioplasty without repair sufficient?
Am J Sports Med 2002;30(2):257–260.
71. Miller SL, Hazrati Y, Cornwall R, et al. Failed
surgical management of partial thickness rotator
cuff tears. Orthopedics 2002;25(11):1255–1257.
72. Ruotolo C, Fow JE, Nottage WM. The supraspi-
natus footprint: an anatomic study of the su-
praspinatus insertion. Arthroscopy 2004;20(3):
73. Wright SA, Cofield RH. Management of partial-
thickness rotator cuff tears. J Shoulder Elbow
74. Paley KJ, Jobe FW, Pink MM, Kvitne RS, ElAt-
trache NS. Arthroscopic findings in the overhand
throwing athlete: evidence for posterior internal
impingement of the rotator cuff. Arthroscopy
75. Lo IK, Burkhart SS. Arthroscopic repair of mas-
sive, contracted, immobile rotator cuff tears using
single and double interval slides: technique and
preliminary results. Arthroscopy 2004;20(1):22–
76. Burkhart SS, Johnson TC, Wirth MA, Athana-
siou KA. Cyclic loading of transosseous rotator
cuff repairs: tension overload as a possible cause
of failure. Arthroscopy 1997;13(2):172–176.
77. Davidson PA, Rivenburgh DW. Rotator cuff re-
pair tension as a determinant of functional out-
come. J Shoulder Elbow Surg 2000;9(6):502–
78. McLaughlin HL. Lesions of the musculotendi-
nous cuff of the shoulder: the exposure and treat-
ment of tears with retraction—1944. Clin Orthop
Relat Res 1994;304:3–9.
79. Burkhart SS. A stepwise approach to arthro-
scopic rotator cuff repair based on biomechanical
principles. Arthroscopy 2000;16(1):82–90.
80. Gazielly DF, Gleyze P, Montagnon C, Bruyere
G, Prallet B. Functional and anatomical results
after surgical treatment of ruptures of the rotator
cuff. 1: preoperative functional and anatomical
evaluation of ruptures of the rotator cuff [in
French]. Rev Chir Orthop Reparatrice Appar
81. Warner JJ, Higgins L, Parsons IM 4th, Dowdy P.
Diagnosis and treatment of anterosuperior rota-
tor cuff tears. J Shoulder Elbow Surg 2001;10(1):
82. Mansat P, Frankle MA, Cofield RH. Tears in the
subscapularis tendon: descriptive analysis and
results of surgical repair. Joint Bone Spine 2003;
83. Aluisio FV, Osbahr DC, Speer KP. Analysis of
rotator cuff muscles in adult human cadaveric
specimens. Am J Orthop 2003;32(3):124–129.
84. Parsons IM, Apreleva M, Fu FH, Woo SL. The
effect of rotator cuff tears on reaction forces at
the glenohumeral joint. J Orthop Res 2002;20(3):
85. Kempf JF, Gleyze P, Bonnomet F, et al. A multi-
center study of 210 rotator cuff tears treated by
arthroscopic acromioplasty. Arthroscopy 1999;
86. Walch G, Marechal E, Maupas J, Liotard JP.
Surgical treatment of rotator cuff rupture. Prog-
nostic factors [in French]. Rev Chir Orthop
Reparatrice Appar Mot 1992;78(6):379–388.
87. Farin PU, Jaroma H, Soimakallio S. Medial dis-
placement of the biceps brachii tendon: evalua-
RG f Volume 26
● Number 4
tion with dynamic sonography during maximal
external shoulder rotation. Radiology 1995;
88. Post M, Silver R, Singh M. Rotator cuff tear: di-
agnosis and treatment. Clin Orthop Relat Res
89. Maughan RJ, Watson JS, Weir J. Strength and
cross-sectional area of human skeletal muscle.
J Physiol 1983;338:37–49.
90. Tingart MJ, Apreleva M, Lehtinen JT, Capell B,
Palmer WE, Warner JJ. Magnetic resonance im-
aging in quantitative analysis of rotator cuff
muscle volume. Clin Orthop Relat Res 2003;
91. Iannotti JP, Zlatkin MB, Esterhai JL, Kressel
HY, Dalinka MK, Spindler KP. Magnetic reso-
nance imaging of the shoulder: sensitivity, speci-
ficity, and predictive value. J Bone Joint Surg Am
92. Thomazeau H, Rolland Y, Lucas C, Duval JM,
Langlais F. Atrophy of the supraspinatus belly:
assessment by MRI in 55 patients with rotator
cuff pathology. Acta Orthop Scand 1996;67(3):
93. Zanetti M, Gerber C, Hodler J. Quantitative as-
sessment of the muscles of the rotator cuff with
magnetic resonance imaging. Invest Radiol 1998;
94. Schaefer O, Winterer J, Lohrmann C, Lauben-
berger J, Reichelt A, Langer M. Magnetic reso-
nance imaging for supraspinatus muscle atrophy
after cuff repair. Clin Orthop Relat Res 2002;
95. Goutallier D, Postel JM, Gleyze P, Leguilloux P,
Van Driessche S. Influence of cuff muscle fatty
degeneration on anatomic and functional out-
comes after simple suture of full-thickness tears.
J Shoulder Elbow Surg 2003;12(6):550–554.
96. Goutallier D, Postel JM, Lavau L, Bernageau J.
Impact of fatty degeneration of the supraspinatus
and infraspinatus muscles on the prognosis of
surgical repair of the rotator cuff [in French]. Rev
Chir Orthop Reparatrice Appar Mot 1999;85(7):
97. Goutallier D, Postel JM, Bernageau J, Lavau L,
Voisin MC. Fatty muscle degeneration in cuff
ruptures: pre- and postoperative evaluation by
CT scan. Clin Orthop Relat Res 1994;304:78–
98. Nakagaki K, Ozaki J, Tomita Y, Tamai S. Fatty
degeneration in the supraspinatus muscle after
rotator cuff tear. J Shoulder Elbow Surg 1996;
99. Gerber C, Meyer DC, Schneeberger AG, Hop-
peler H, von Rechenberg B. Effect of tendon re-
lease and delayed repair on the structure of the
muscles of the rotator cuff: an experimental study
in sheep. J Bone Joint Surg Am 2004;86-A(9):
100. Natsen FA, Arntz CT, Lippit SB. Rotator cuff.
In: Rockwood CA, Matsen FA 3rd, eds. The
shoulder. Philadelphia, Pa: Saunders, 1998; 755–
101. Nakagaki K, Ozaki J, Tomita Y, Tamai S. Func-
tion of supraspinatus muscle with torn cuff evalu-
ated by magnetic resonance imaging. Clin Or-
thop Relat Res 1995;318:144–151.
102. Pfirrmann CW, Schmid MR, Zanetti M, Jost B,
Gerber C, Hodler J. Assessment of fat content in
supraspinatus muscle with proton MR spectros-
copy in asymptomatic volunteers and patients
with supraspinatus tendon lesions. Radiology
103. Fongemie AE, Buss DD, Rolnick SJ. Manage-
ment of shoulder impingement syndrome and
rotator cuff tears. Am Fam Physician 1998;
104. Bigliani LU, Ticker JB, Flatow EL, Soslowsky
LJ, Mow VC. Relationship of acromial architec-
ture and diseases of the rotator cuff [in German].
105. Toivonen DA, Tuite MJ, Orwin JF. Acromial
structure and tears of the rotator cuff. J Shoulder
Elbow Surg 1995;4(5):376–383.
106. Yazici M, Kopuz C, Gulman B. Morphologic
variants of acromion in neonatal cadavers. J Pedi-
atr Orthop 1995;15(5):644–647.
107. Vanarthos WJ, Monu JU. Type 4 acromion: a
new classification. Contemp Orthop 1995;30(3):
108. Banas MP, Miller RJ, Totterman S. Relationship
between the lateral acromion angle and rotator
cuff disease. J Shoulder Elbow Surg 1995;4(6):
109. Swain RA, Wilson FD, Harsha DM. The os ac-
romiale: another cause of impingement. Med Sci
Sports Exerc 1996;28(12):1459–1462. [Pub-
lished correction appears in Med Sci Sports Ex-
110. Gagey N, Ravaud E, Lassau JP. Anatomy of the
acromial arch: correlation of anatomy and mag-
netic resonance imaging. Surg Radiol Anat 1993;
111. Gumina S, Postacchini F, Orsina L, Cinotti G.
The morphometry of the coracoid process: its
aetiologic role in subcoracoid impingement syn-
drome. Int Orthop 1999;23(4):198–201.
112. Tan V, Moore RS Jr, Omarini L, Kneeland JB,
Williams GR Jr, Iannotti JP. Magnetic resonance
imaging analysis of coracoid morphology and its
relation to rotator cuff tears. Am J Orthop 2002;
113. Nove-Josserand L, Boulahia A, Levigne C, Noel
E, Walch G. Coraco-humeral space and rotator
cuff tears [in French]. Rev Chir Orthop Reparatrice
Appar Mot 1999;85(7):677–683.
RG f Volume 26
● Number 4Morag et al 1065
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RG Volume 26 • • Volume 4 • • July-August 2006 Morag et al
MR Imaging of Rotator Cuff Injury: What the Clinician Needs to
Yoav Morag, MD, et al
The dimensions of rotator cuff tears may have implications for selection of treatment and surgical
approach, postoperative prognosis, and tear recurrence.
It has been suggested that a tear is suspected to be irreparable if MR imaging depicts retraction of the
tendon edge medial to the glenoid fossa (Fig 9) (52).
A supraspinatus tendon tear may extend anteriorly to involve the medial aspect of the coracohumeral
ligament and superior subscapularis tendon fibers, a situation that is associated with more severe
supraspinatus atrophy and poor prognosis (Fig 11) (52).
If the ratio of the cross-sectional area of the supraspinatus muscle to the area of the supraspinatus
fossa (occupation ratio) is less than 50% in the sagittal oblique plane, supraspinatus muscle atrophy is
indicated (Figs 17, 18). In a study by Thomazeau et al (92), supraspinatus muscle atrophy as
determined with this method correlated with extent of tendon tear and was associated with tear
recurrence after surgical repair.
Fatty degeneration is an important predictive factor for surgical outcome (38,95–97,100).
RadioGraphics 2006; 26:1045–1065●Published online 10.1148/rg.264055087●Content Codes: