Diagram 2-5 12 (with modifications). Bicipital Groove .... Third only to low back pain and carpal tunnel syndrome, ..... arrow). It's location on top of the shoulder, requires a coronal ..... The ultrasound findings for the more advanced tenosynovitis.
SHOULDER ULTRASOUND TECHNIQUES Prof. Dr. Syed Amir Gilani M.B; B.S (Pb), DMRD MPH, PhD Anatomy of the Shoulder
The shoulder girdle, or pectoral girdle as it is also known, is composed of two main components on either side; the scapulae posteriorly and the clavicles anteriorly. The Scapula
This triangular shaped bone makes up the posterior aspect of the shoulder girdle. Between the two processes of the scapula, sits the glenoid cavity or fossa, a hollow depression which articulates with the head of the humerus to form the shoulder joint.
The Clavicle
These slender, S-shaped bones course almost horizontally across either side of the chest from the base of the neck to the shoulder joint. Medially, each clavicle articulates with the sternum at the level of the manubrium. The lateral end of each clavicle articulates with the acromion process of the scapula to form the acromioclavicular (or AC) joint.
The Shoulder Joint
The head of the humerus and the glenoid cavity of the scapula articulate to form a ball and socket joint at the shoulder, known as the glenohumeral joint. This joint is protected superiorly by the two processes of the scapula, the acromion and coracoid processes and is held together by various muscles and fibrous connective tissues, which we shall discuss shortly.
The Rotator Cuff
The rotator cuff is considered the dynamic stabilizer of the shoulder joint. The static stabilizers are the shoulder joint capsule and the labrum complex, including the glenohumeral ligaments. The rotator cuff comprises four muscles and their musculotendinous attachments; The Rotator Cuff
Subscapularis Supraspinatus Infraspinatus Teres minor
The Rotator Cuff
Let's locate each of these structures now. Please refer to Diagram 2-3 below as we continue.
) Diagram 2-4 1 (with modifications) Diagram 2-5 12 (with modifications) Bicipital Groove
The bicipital groove averages 4.3 mm in depth. Grooves which are less than 3 mm deep are considered shallow, with a higher risk of LHB dislocation or subluxation. Diagram 2-6 12 (with modifications)
Finally, the biceps tendon, along with the rotator cuff, serves to stabilize the head of the humerus within the shoulder joint. The supraspinatus and infraspinatus muscles both originate on the scapula and insert on the greater tuberosity. The teres minor muscle also originates on the scapula and inserts on the greater tuberosity. The subacromial space lies underneath the acromion, the
coracoid process, the acromioclavicular joint and the coracoacromial ligament. bursa in the subacromial space
which serves to provide lubrication for the rotator cuff. This space becomes more important a little later on when we discuss the topic of shoulder impingement.
The coracohumeral ligament (short white arrow) is also identified. The black arrow indicates the tendon of the supraspinatus muscle, which is not well seen from this view. Diagram 2-8 12 (with modifications)
In addition to the four tendons which form the rotator cuff, four important ligaments also serve to prevent dislocation of the shoulder joint. These include; coracohumeral ligament - a broad band of connective tissue that connects the coracoid process of the scapula to the greater tubercle of the humerus glenohumeral ligament - three separate bands of fibers within the ventral wall of the joint capsule, which connect the edge of the glenoid fossa to the lesser tubercle and anatomical neck of the humerus transverse humeral ligament - a narrow sheet of connective tissue running between the greater and lesser tubercles of the humerus, creating a canal through which the long head of the biceps tendon passes glenoid labrum - a fibrocartilage ligament attached along the margin of the glenoid cavity, forming a rim which serves to make the cavity deeper
Take a look at Diagram 2-9, illustrating the tendons and ligaments of the shoulder, before we finish up this anatomical discussion by reviewing the shoulder bursae and finally, the outer layer of muscles. Diagram 2- 9 1 (with modifications)
Several bursae are associated with the shoulder joint. These include; • the subscapular bursa - located between the joint capsule and the tendon of the subscapularis muscle the subdeltoid bursa located between the joint capsule and the deep surface of the deltoid muscle the subacromial bursa - located between the under surface of the acromion process of the scapula and the joint capsule the subcoracoid bursa - located between the coracoid process of the scapula and the joint capsule of the four bursae, the subscapular bursa is usually continuous with the synovial capsule surrounding the shoulder joint. The other bursae do not communicate with the joint cavity, but may communicate with each other as seen in Diagram 2-10 below.
Diagram 2-10, illustrates two of the four bursae for us. The subscapular bursae is outlined in Diagram 2-9 and subcoracoid bursa is not seen. Diagram 2-10 1 (with modifications) Muscles of the Shoulder
Now that we've worked our way to the most superficial layer of tissue, let's take some time to review the anatomy of the muscles that are responsible for moving the upper arm. Diagram 2-11 immediately below illustrates these muscles for us. Diagram 2-11 8 (with modifications)
Once again, the muscles illustrated above are combined into four separate groups, based on their primary action or function. These include flexors and extensors as well as abductors and rotators. We've already covered the rotators in our discussion of the
rotator cuff, so let's finish up by reviewing the other muscle groups of the upper extremity, beginning with the flexors. Flexors of the Upper Arm
You'll recall from earlier discussions of muscles which move the forearm, that in order to flex a given body part, the group of muscles responsible for flexion must originate proximal to the part to be moved. The upper arm flexors consist of two muscles; the coracobrachialis and the pectoralis major. Let's review their origins and function now. Flexors of the Upper Arm
The coracobrachialis muscle originates on the coracoid process of the scapula and attaches to the mid humerus on its medial surface. It is responsible for flexion and adduction of the upper arm. Flexors of the Upper Arm
The pectoralis major muscle is located on the upper chest extending from the center of the thorax across the shoulder girdle to attach on the humerus. It is responsible for pulling the arm across the chest as well as medial rotation and adduction of the humerus. Extensors of the Upper Arm
Two muscles make up the extensor group of the upper arm; the teres major and the latissimus dorsi. Diagram 2-12 on the following page illustrates their location and relation to the other groups. Let's quickly review their attachments. Extensors of the Upper Arm
The teres major muscle connects the scapula to the humerus, serving to extend the humerus as well as adduct and rotate the upper arm medially. Extensors of the Upper Arm
The latissimus dorsi muscle is a very wide, triangular muscle covering the lower back and side of the thorax. Its connection to the humerus allows extension and adduction of the upper arm, also serving to pull the shoulder down and back. Abductors of the Upper Arm
Two muscles serve to abduct the upper arm; the supraspinatus
and the deltoid muscles. The supraspinatus muscle, already covered in our review of the rotator cuff, is located posteriorly in the depression above the spine of the scapula.
It connects the scapula to the greater tuberosity of the humerus and acts to abduct the upper arm (as well as stabilize the shoulder joint as part of the rotator cuff). The deltoid muscle will become very familiar to you, as it is visualized in most ultrasound scans of the rotator cuff. The deltoid muscle covers the shoulder joint, connecting the clavicle and scapula to the lateral side of the humerus, serving to abduct the upper arm.
In addition to its abduction duties, the posterior fibers of the deltoid muscle help extend the humerus while its anterior fibers assist in flexion of the humerus. Quite a versatile muscle! Diagram 2-12 8 (with modifications)
Now that we've concluded our review of shoulder anatomy, it's time to move on and discuss the most common indications for shoulder ultrasound. Let's forge ahead! Indications for Shoulder Ultrasound
Ultrasound of the shoulder, particularly of the rotator cuff is one of the most common MSK ultrasound examinations performed today. Indications for Shoulder Ultrasound
Third only to low back pain and carpal tunnel syndrome, shoulder pain is extremely common, especially in patients over the age of 40. Ease of access to the shoulder joint allows for the investigation of many disorders, including Indications for Shoulder Ultrasound
• rotator cuff tears (both partial and full thickness) • subdeltoid-subacromial bursitis • biceps tendonitis or tenosynovitis
• gleno-humeral joint effusion Indications for Shoulder Ultrasound
Patient's suffering from rotator cuff disease typically complain of a dull, chronic ache in their shoulder, which prevents them from raising their arm (i.e. performing actions like combing their hair), or an inability to raise their arm above their shoulder. Many patients have difficulty sleeping on the affected side. Indications for Shoulder Ultrasound
While relatively uncommon before the age of 30, rotator cuff tears become increasingly common with age and are present in the majority of the population over the age of 70. Indications for Shoulder Ultrasound
We shall discuss rotator cuff tears as well as the other potential disorders in more detail later on. Next, let's review the examination technique, including patient positioning and scanning protocols. Patient Positioning
Ideally, the patient is examined while sitting on a low stool with a rotating, backless seat, allowing access to the front, side and posterior aspects of their shoulder. The examiner is seated adjacent and lateral to the affected shoulder. The arm is placed in a neutral position to begin the examination. Patient Positioning
Although the patient can be examined in a supine position, they must be turned to lie prone in order to examine the posterior components of the rotator cuff. Obviously a sitting position should be used if possible! Scanning Technique
Ultrasound examination of the rotator cuff is best performed with a high resolution, high frequency (7.5-12 MHz) linear array transducer, or possibly a curved array of similar frequency where appropriate. Once the transducer has been selected and system settings optimized, the rotator cuff is examined in the following order: Rotator Cuf f Ultrasound
TECHNIQUES
AFRO-ASIAN INSTITUTE OF MEDICAL SCIENCES LAHORE, PAKISTAN
Rotator Cuf f
Supraspinatus Infraspinatus Teres Minor Subscapularis Long Head of Biceps
Technique: position #1
Neutral, supination
hand on lap, palm up anterior (7-13 MHz) biceps long head tendon:
▪ transverse, longitudinal Technique: position #1
To find biceps longitudinal
use bone landmarks find lesser tuberosity: pyramid shape
move lateral to bicipital groove Technique: position #2
External Rotation
anterior (7-13 MHz linear) subscapularis tendon:
▪
transverse, longitudinal
biceps tendon subluxation Technique: position #3 Neutral position
arm down at side lateral (7-13 MHz linear) acromioclavicular joint subacromial-subdeltoid bursa Technique: position #4 Neutral position
posterior (5 - 12 MHz) infraspinatus tendon posterior labrum
▪ spinoglenoid notch: labral cyst Technique: position #5 Internal rotation, extension
hand at opposite back pocket anterior (7-13 MHz linear) supraspinatus
▪
start longitudinal
infraspinatus Technique: position #5
Alternate position
hand at closest hip pocket easier to tolerate longitudinal: oblique plane toward Supraspinatus Tendon: normal Hyperechoic Fibrillar echotexture Convex superior surface Uniform thickness: transverse
Supraspinatus - Infraspinatus Junction
2 - 2.5 cm posterior to biceps tendon Slight volume loss Interdigitation of fibers Flattening of greater tuberosity: longitudinal
Rotator Cuf f Tears:
General comments Secondary signs of rotator cuff tear Pitfalls in rotator cuff sonography
Rotator Cuf f Tears:
Established criteria*: Complete absence of rotator cuf f Focal non-visualization Discontinuity of tendon fibers Abnormal focal echogenicity
elbow
173:323 Rotator Cuf f Tears:
Soble et al. Radiology 1989;
General comments:
Most tears are hypoechoic Larger tears: deltoid dips into Massive tear: non-visualization
tendon gap
Rotator Cuf f Abnormalities:
Categories: Partial-thickness tear Full-thickness tears Intra-substance abnormality
severe tendinosis or intrasubstance tear
Tendinosis Supraspinatus: normal Partial-thickness Tear:
Usually hypoechoic
May see hyperechoic fiber stump*
Articular or bursal side Associated cortical irregularity Little if any tendon volume loss
Unless bursal location
van Holsbeeck et al. Radiology 1995; 197:443 Articular Partial-thickness Tear: supraspinatus Bursal Partial-thickness Tear: supraspinatus Small Full-thickness Tear:
Hypoechoic (surface to surface)
Volume loss: minimal or absent May be difficult to differentiate from tear Volume loss suggests full-thickness tear
partial-thickness
Small Full-thickness Tear: supraspinatus Large Full-thickness Tear:
Hypoechoic disruption of (1-3 cm) Articular to bursal surface Fluid or granulation tissue Volume loss of tendon substance
tendon fibers
Large Full-thickness Tear: supraspinatus Massive Full-thickness Tear:
Non-visualization of cuf f: 100% positive predictive value* Supraspinatus retracted beneath
acromion
Deltoid approximated to humerus Infraspinatus extension if
146:555 Massive Tear: supraspinatus Intra-substance Abnormality:
width (AP) >2.5 cm *Middleton et al. AJR 1985;
Could represent severe degeneration or Anechoic or hypoechoic Well defined
Intra-substance Abnormality:
intrasubstance tear
Does not extend to articular or isolated gr. tuberosity extension More anechoic and defined than
Intrasubstance Abnormality: supraspinatus Tendinosis:
bursal surface
tendinosis
Tendon degeneration No significant inflammatory cells* Tendinosis is preferred over tendinitis
Tendinosis:
*Kjellin et al. Radiology 1991; 181:837
Focal or diffuse Hypoechoic Not well defined Possible tendon swelling No cortical irregularity
Focal Tendinosis: supraspinatus Tendinosis: supraspinatus Rotator Cuf f Tears:
General comments Secondary signs of rotator cuff tear Pitfalls in rotator cuff sonography
Secondary Findings of Rotator Cuf f Tears: Tendon Volume Loss:
Flat or concave outer margin of Deltoid muscle dips into tendon gap Implies significant fiber loss Tendon Volume Loss:
supraspinatus*
*Hodler et al. Radiology 1988; 169:791
Seen with full-thickness less commonly extensive partial-thickness especially bursal Differentiates full-thickness tear from
tears -
partial-thickness tear Secondary Findings of Rotator Cuf f Tears: Cortical Irregularity:
Greater tuberosity When present: 75% have rotator When absent: 96% normal cuf fs by
cuf f tears sonography
Usually not seen with tendinosis
171:229 Secondary Findings of Rotator Cuf f Tears: Joint & Bursal Ef fusions:
Wohlwend et al. AJR 1998;
Joint effusion (biceps tendon) Subacromial-subdeltoid bursal fluid: >1 mm distention
If both: 95% PPV rotator cuff tear* Secondary Findings of Rotator Cuf f Tears:
*Hollister et al. AJR 1995; 165:605
Cartilage Interface Sign:
Reflective interface between hyaline cartilage and adjacent fluid Indicates articular extension of tear Limited value Rotator Cuf f Tears: General comments Secondary signs of rotator cuff tear Pitfalls in rotator cuff sonography
hypoechoic
Pitfall: technique
Improper arm position Improper Arm Position: Inadequate internal rotation/extension Supraspinatus is hidden beneath Pitfall: technique Improper arm position Incomplete evaluation of the Incomplete Evaluation of
acromion
supraspinatus
Supraspinatus:
Scan entire width of greater tuberosity
Most tears occur anteriorly Include biceps on transverse image Pitfall: technique Improper arm position Incomplete evaluation of the Transverse imaging too distal
as landmark
supraspinatus
Transverse Imaging: supraspinatus
Uniformly thins over greater tuberosity Cuff absent beyond greater tuberosity Confirm with orthogonal longitudinal
imaging
Pitfall: misinterpretation of normal
Rotator interval
Misinterpretation of Rotator Interval:
Intra-articular portion of biceps tendon Hyperechoic Adjacent hypoechoic gap* May simulate tear
*Middleton et al. AJR 1986; 146:555 Pitfall: misinterpretation of normal
Rotator interval Musculotendinous junction
Supraspinatus Subscapularis Musculotendinous Junction:
Supraspinatus: several distinct tendons Appears as hypoechoic area extending Usually terminates by mid-tendon Characteristic tapering from proximal to Musculotendinous Junction: Subscapularis: several distinct tendons Appears as hypoechoic area extending Heterogeneous to lesser tuberosity Pitfall: misinterpretation of normal Rotator interval Musculotendinous junction Supraspinatus - infraspinatus junction Supraspinatus - Infraspinatus Junction
Converging fibers - posterior Hypoechoic fibers: anisotropy Regular intervals
Pitfall: subacromial-subdeltoid bursa
Bursal thickening simulating intact cuff
into tendon
distal
into tendon
Subacromial-subdeltoid Bursa:
Hyperechoic synovium may appear Hyperechoic thickness that extends
is synovium and not cuf f fibers Pitfall: subacromial-subdeltoid bursa
similar to tendon fibers beyond greater tuberosity
Bursal thickening simulating intact cuff Bursal wall simulating intact cuff Pseudofibers with full-thickness tear: Hyperechoic and fibrillar Typically thinner than normal cuff Extends beyond greater tuberosity Pitfall: dif ferentiating pathology Full-thickness vs. partial-thickness tear Full-thickness vs. Tear:
Partial-thickness
Volume loss suggests full-thickness tear Hyperechoic cartilage interface indicates articular surface
extension Pitfall: dif ferentiating pathology
Full-thickness vs. partial-thickness tear Tendon tear vs. tendinosis
Tendon Tear versus Tendinosis Tendinosis
swollen hypoechoic ill-defined heterogeneous
smooth cortex Tear
thinned anechoic well-defined more homogeneous
bone irregularity Pitfall: dif ferentiating pathology
Full-thickness vs. partial-thickness tear Tendon tear vs. tendinosis Rim-rent tear vs. intrasubstance
Rim-rent Tear vs. Abnormality:
Extension to gr. tuberosity: tear / tendinosis Extension to articular surface tuberosity:
abnormality Intra-substance intra-substance
adjacent to gr. rim-rent tear (partial-thickness)
Tuite et al. Skeletal Radiol 1998; 27:237 Miscellaneous Cuf f Pathology:
Infraspinatus tendon Subscapularis tendon Post-operative cuff Calcific tendinitis
Infraspinatus Tear:
Isolated tear: rare, trauma Part of massive cuff tear: If supraspinatus tear, look for extension
Tear extends >2.5 cm from rotator interval
image Supraspinatus Tear: no infraspinatus tear Miscellaneous Cuf f Pathology:
on transverse
Infraspinatus tendon Subscapularis tendon Post-operative cuff Calcific tendinitis
Subscapularis Tear:
Isolated tear: rare, trauma Part of massive cuff tear Anterosuperior cuff tear: supraspinatus and subscapularis borders interval
of the rotator
Pfirrmann et al. Radiology 1999; 213:709 Miscellaneous Cuf f Pathology:
Infraspinatus tendon Subscapularis tendon Post-operative cuff Calcific tendinitis
Post-operative Rotator Cuf f:
Post-op tendon: echogenic & thin* Reimplantation trough Echogenic sutures & anchors
Post-operative Rotator Cuf f:
*Mack et al. AJR 1988; 150:1089
Recurrent tear: usually large with nonvisualization Focal hypoechogenicity: equivocal
Miscellaneous Cuf f Pathology:
Infraspinatus tendon Subscapularis tendon Post-operative cuff Calcific tendinitis
Calcific Tendinitis
Calcium hydroxyapatite deposition Localize, guided aspiration Appearance: 79% hyperechoic & shadowing No shadow: 7%
Miscellaneous Cuf f Pathology:
Impingement syndrome Adhesive capsulitis Amyloid deposition Quadrilateral space syndrome
Impingement Syndrome:
Cuff impingement Subacromial enthesophyte or joint osteophyte Associated tendon degeneration
Impingement: US criteria
Subacromial-subdeltoid bursal fluid Pooling of bursal fluid at acromion elevation
acromioclavicular and tear
tip with active arm
*Farin et al. Radiology 1990; 176:845 Miscellaneous Cuf f Pathology:
Impingement syndrome Adhesive capsulitis Amyloid deposition Quadrilateral space syndrome
Adhesive Capsulitis:
Caused by shoulder immobilization Supraspinatus tendon does not acromion with lateral
slide beneath elevation of arm
Ryu et al. J Ultrasound Med 1993; 12:445 Adhesive Capsulitis:
Diagnosis with sonography:
Sensitivity 91% Specificity 100%
Accuracy 92% Miscellaneous Cuf f Pathology: Impingement syndrome Adhesive capsulitis Amyloid deposition Quadrilateral space syndrome Amyloid Deposition:
Rotator cuff > 7 mm thick Thickened synovium SA-SD bursal swelling >1 mm Soft tissue nodules
166:153 Miscellaneous Cuf f Pathology:
Cardinal et al. AJR 1996;
Impingement syndrome Adhesive capsulitis Amyloid deposition Quadrilateral space syndrome
Quadrilateral Space Syndrome
Axillary nerve entrapment Teres minor, teres major, long head of shaft Weakness, pain and skin paresthesia Post. humeral circumflex art occlusion
triceps, and humeral
Teres minor and/or deltoid atrophy Results: Variable results in diagnosing cuff Sensitivity: 33-100%* Results:
tears
*Orthop Clin North Am 1998; 29:135
Operator dependent Use of different ultrasound criteria Use of different gold standards Summary: advantages Dynamic exam Noninvasive, well-tolerated Available Accuracy equal or better than MRI Less expensive: 1/4 cost of MRI Summary: disadvantages Operator dependence However, can be minimized with and standardized Algorithm:
technique
Suspect labrum (age < 35 yrs): MR arthrography Suspect cuff pathology (age > 40 yrs): Ultrasound Unclear etiology (intermediate age):
proper training
MR imaging (no contrast)
1.
long head of the biceps tendon (LHB)
2.
subscapularis tendon
3.
supraspinatus, infraspinatus and teres minor tendons
Let's review the entire examination, beginning with imaging the LHB tendon first. Refer to Diagrams 2-13 and 2-14, which follow, as we continue. Diagram 2-13 11 (with modifications)
Ultrasound examination of the rotator cuff begins with the affected arm in a neutral position. This position is illustrated in Diagram 2-13 on the previous page. It is useful to have the patient sit on a revolving stool, in order to position the patient optimally for each of the views necessary to complete the shoulder examination. We begin by imaging the biceps tendon in a transverse plane (see the transducer position in Diagram 2-14 below), beginning at the proximal third of the humerus where the long head of the biceps tendon is located within the bicipital groove. After imaging the biceps tendon within the bicipital groove, deep to the transverse humeral ligament, follow the tendon superiorly as far as possible to the origin of the tendon at the supraglenoid tubercle and glenoid labrum. Although the origin is usually not visible, you should be able to demonstrate the biceps tendon as an oval shaped, echogenic structure between the subscapularis tendon anteromedially and the supraspinatus tendon posterolaterally.
This area is called the rotator cuff interval. Atlas Figure 2.1 illustrates a normal, high resolution ultrasound scan of the rotator cuff interval. Diagram 2-1414 (with modifications)
Once you've determined that the tendon is not dislocated or subluxed, the transducer is rotated 90° to a longitudinal orientation, in order to follow the length of the biceps tendon, beginning between the greater and lesser tuberosities of the humerus. Diagram 2-15 on the following page illustrates the proper transducer position. You are looking for the normal, fibrillar pattern displayed by all tendons, as well as evidence of fluid within the synovial sheath, which may represent tendonitis. Let's look at two normal scans of the biceps tendon in both of these planes. Check out Atlas Figures 2-2 and 2-3 before we move on.
The biceps tendon is seen as an echogenic focus with an ovoid shape situated within the bicipital groove between the greater and lesser tuberosities of the humerus. Diagram 2-1514 (with modifications)
Next, using a similar transducer position to that just used to examine the biceps tendon in long axis, the subscapularis tendon is examined in a transverse plane, first with the arm in neutral position, then during and following external rotation of the arm. Diagram 2-15 above illustrates this position for us. Remember, the subscapularis muscle and tendon lie horizontally at the front of the shoulder, therefore, in order to examine these structures in a transverse plane (or short axis), the transducer will be oriented longitudinally.
Recall that the subscapularis tendon is seen inserting into the lesser tuberosity medial to the bicipital groove in Atlas Figure 2.2. Once you've identified its location, simply slide the transducer medially to image more of the tendon in a transverse plane. You should also be aware that the subacromial subdeltoid (SA-SD) bursa is located superficial to the subscapularis tendon and just deep to the subdeltoid fat. This bursa is normally no greater than 2 mm in size and when fluid is present within the bursa, this view should visualize it. We'll take a look at a normal and an abnormal subacromial subdeltoid bursa a little later on. Finally, note that the tendon is more echogenic than the deltoid muscle. Atlas Figure 2.4 illustrates a normal subscapularis tendon in the transverse view. Note the deltoid muscle (labeled D) superficially, as well as the humeral head (labeled H) and lesser tuberosity (labeled LT). After imaging the subscapularis tendon transversely, with the arm both internally and externally rotated, the transducer is rotated 90°, to a transverse plane and the subscapularis tendon is imaged in the longitudinal plane in its entirety once again. Refer to Diagram 2-16 below, illustrating the transducer position necessary to image the subscapularis tendon longitudinally. Once again, this position is slightly medial and slightly more cranial in position to that used to image the biceps tendon transversely within the bicipital groove, as indicated by the black arrows. Atlas Figure 2.5 illustrates the subscapularis tendon in a longitudinal plane for us. Note how it inserts into the lesser
tubercle or tuberosity (labeled LT) of the humerus.
The appearance of the insertion into the lesser tuberosity is described as beak shaped, pointing to the right for the right subscapularis and to the left when imaging the left subscapularis tendon. Diagram 2-1614 (with modifications)
Next, the supraspinatus and infraspinatus tendons are imaged with the arm hyperextended and internally rotated. Diagrams 2-17 and 2-18, on the following page, demonstrate the correct transducer positions necessary to image the supraspinatus tendon in two planes. First, with the transducer in a longitudinal plane (Diagram 2-17), the supraspinatus is imaged as it attaches to the greater tuberosity of the humerus. Using the same transducer plane, the entire supraspinatus tendon is then imaged in long axis.
Then, the transducer is rotated 90° to image the supraspinatus in short axis (Diagram 2-18). Remember to image the entire tendon, by moving the probe from the shoulder towards the neck. Diagram 2-1714 (with modifications) Diagram 2-1814 (with modifications)
Atlas Figure 2.6 illustrates a normal supraspinatus tendon in the longitudinal plane while Atlas Figure 2.7 demonstrates the supraspinatus tendon in the short axis.
Next, move the transducer further laterally and slightly posteriorly to evaluate the infraspinatus tendon and its insertion into the humerus. Diagram 2-19, below illustrates the correct transducer position for us. Diagram 2-1914 (with modifications)
Atlas Figure 2.8 provides us with a normal image of the infraspinatus tendon in a transverse plane and Atlas Figure 2.9 is an image of the infraspinatus tendon in a longitudinal plane. It is also possible to image both the supra and infraspinatus tendons in a transverse, or short axis plane and Atlas Figure 2.10 provides us with just such an image. While we're examining the posterior aspect of the shoulder, don't forget to evaluate the posterior labrum of the scapula for evidence of an effusion or cyst, which may separate the infraspinatus tendon from the glenoid. Atlas Figure 2.11 demonstrates a normal glenoid labrum (white arrows) for us. If indicated, the teres minor tendon, located posteriorly and inferiorly, can also be imaged at this point in the examination.
Complete examination of the rotator cuff also requires imaging of the acromioclavicular (AC) joint. Diagram 2-20 on the following page, illustrates the position of the AC joint (white arrow). It's location on top of the shoulder, requires a coronal transducer plane in order to image the joint optimally. Diagram 2-20 12 (with modifications)
illustrates a normal acromioclavicular (AC) joint in a coronal plane. After the patient's arm is placed in a neutral position, the transducer is placed in a coronal orientation, directly over the acromion (labeled ACR), then moved medially until the AC joint is identified. Remember to take comparison views of both sides. demonstrates a case of AC joint separation. Comparison views with the normal side are especially useful for revealing the degree of separation.
Finally, the most common pathology of the AC joint is osteoarthritis, so be sure to look for bony changes!
Well, this completes our discussion of normal structures and images of the shoulder and rotator cuff in particular. Next, we'll delve into the abnormal, discussing the most common MSK abnormalities of the shoulder. Read on! Rotator Cuff Pathology
When it comes to pathology of the rotator cuff, most people immediately think of a rotator cuff tear. Although rotator cuff fiber failure is common, there are many other pathological processes which may potentially affect the rotator cuff. These include: Rotator Cuff Pathology
• rotator cuff tears; full or partial thickness • calcific tendinitis • joint effusions • biceps tendinitis / tenosynovitis
• biceps tendon rupture and / or dislocation Rotator Cuff Pathology
arthritis / bursitis fracture / labral tear impingement of the rotator cuff
Well, that's a fairly long list of potential pathologies to review, so let's get to it! Rotator Cuff Tears
The most common indication for high resolution ultrasound of the shoulder is to rule out a tear of the rotator cuff. Fiber failure of the rotator cuff tendons begins at approximately twenty one years of age, becoming much more common after the age of forty, ultimately resulting in shoulder pain and generalized dysfunction. Rotator Cuff Tears
Most often involving the supraspinatus tendon, rotator cuff tears have a wide range of appearances and presentations, so let's spend some time reviewing the various types of rotator cuff tears. Rotator Cuff Tears
Ultrasound is quite accurate at making the diagnosis of a rotator cuff tear with an overall accuracy of approximately 96%, as long as appropriate criteria are utilized for making the diagnosis. To that end, four major criteria have been established to make the diagnosis, including;
Rotator Cuff Tears
1. Complete nonvisualization of the cuff - also known as a "bare shoulder" or massive, full thickness tear. With complete absence of the rotator cuff, the deltoid muscle and the subdeltoid bursa sit alone, on top of the proximal humerus, often with bony irregularity of the proximal humerus and thickening of the bursa also present. Rotator Cuff Tears
You may notice a tendon "stump" retracted back towards the body of the muscle. It is also helpful to observe humeral movement in real time to confirm the absence of the cuff. illustrate full thickness rotator cuff tears. In some cases, when the rotator cuff is absent, the humeral head may sit in a more cephalad location, closely abutting the acromion.
Rotator Cuff Tears
2. Localized or focal nonvisualization of the cuff - indicates a less severe, partial thickness rotator cuff tear. These tears occur most often in the anterolateral, critical zone1 of the supraspinatus tendon. Rotator Cuff Tears
On ultrasound examination, localized tears appear as sharply demarcated pieces of rotator cuff, often separated by herniation of the deltoid muscle into the region of the tear. Rotator Cuff Tears
This appearance is known as the deltoid herniation sign. Diagram 2-21 below illustrates the deltoid muscle and fascia herniating into a focal tear of the supraspinatus tendon (black arrows). Diagram 2-21 13 (with modifications)
3. Discontinuity of the cuff - an appearance often seen with smaller rotator cuff tears. This type of tear is usually associated with a fluid collection originating within the glenohumeral area or subacromial subdeltoid (SA-SD) bursa, filling the space within the torn cuff. illustrate discontinuity of the supraspinatus tendon. A double cortex sign is also evident in this case. 4. Abnormal cuff echogenicity - is probably the least reliable indicator of a rotator cuff tear, as the normal echotexture of the cuff may vary with inflammation or fibrosis of an intact cuff. However, a focal area of increased or decreased echogenicity may represent a small rotator cuff tear. The increased echotexture is thought to be due to hemorrhage and/or granulation tissue within the tendon. A hypoechoic lesion visualized in two planes that extends to either the articular or bursal surface is also highly suspicious for a small, focal tear. illustrate a small, partial thickness tear of the supraspinatus tendon with areas of focal hypo and hyperechogenicity. These four major criteria are usually more obvious when the symptomatic shoulder is compared with the normal side. A zone of relative hypovascularity within the supraspinatus tendon, adjacent to the long head of the biceps tendon,
approximately 1 cm from the insertion onto the greater tuberosity, where most cuff tears occur. Remember
Most tears of the supraspinatus tendon occur in the critical zone. Remember
Before we move on to discuss a few minor criteria for rotator cuff tears, let's summarize the possible sonographic findings during high resolution imaging of the rotator cuff in diagrammatic form. Remember
Diagram 2-22 on the following page illustrates the wide range of ultrasound appearances as follows: Remember
The drawings on the left side of the Diagram represent short axis images, while those on the right represent long axis images. A - these two images illustrate a normal supraspinatus tendon. Note the anterior echogenic arc (black arrow) representing the interface between the supraspinatus tendon and the subdeltoid fascia and peritendinous fat. In the long axis view, note the insertion of the tendon into the greater tuberosity of the humerus B - these two images illustrate the possible appearances of a partial thickness tear of the supraspinatus. The short axis view on the left illustrates a focal, hypoechoic area within the tendon while the long axis image represents a dense, echogenic focus within the tendon. Partial thickness tears require further classification, which we'll get into in a moment. C - this small, full thickness tear ( < 1 cm. ) is seen as a discontinuity of the tendon with a focal area of altered echogenicity between the separated tendon (single arrow). Note the loss of the anterior arc and the lack of cuff substance
at the insertion into the greater tuberosity in the long axis view (small arrows).
D - this drawing of a large, full thickness tear ( 1-3 cm. ) also shows a loss of the anterior arc of the supraspinatus tendon with herniation of the deltoid muscle into the void in both short and long axis views. E - this drawing represents a massive tear ( > 3 cm.) with total nonvisualization of the rotator cuff in both short and long axis views. The deltoid fascia and subacromial subdeltoid bursa are noted to sit on top of the humerus (black arrows).
I should note here that full thickness rotator cuff tears allow communication of the glenohumeral joint and the SA-SD bursa, while partial thickness tears do not. Sonographic Appearances of the Rotator Cuff
Once a rotator cuff tear has been identified, it is important to measure the length of the tear in two orthogonal planes (i.e. two planes at 90° to each other). Massive supraspinatus tears may be difficult to measure if the tendon has retracted totally under the acromion. Surgeons also appreciate knowing the distance of the tear from the long biceps tendon, or the bicipital groove if the tendon is torn, subluxed or dislocated. A few pages back I said that partial thickness rotator cuff tears require further classification, so let's classify them now. Classification of Partial Thickness Rotator Cuff Tears Although partial thickness tears tend to be entirely intratendinous, there are variations, so let's review the three types of partial thickness tears now, including;
• intrasubstance - most common type of partial thickness tear • articular surface - second most common, this category of partial thickness tear includes the rim rent; an early tear of the supraspinatus within the critical zone of the tendon, usually associated with a focal cortical irregularity of the humerus • bursal surface - least common The location of each type of partial thickness tear is self explanatory; simply look at the name!
Well, we've covered a lot of material that we need to remember when performing rotator cuff ultrasound, so I've summarized a few of the more important points for you below. You might want to commit these points to memory for exam purposes! Remember
Always measure rotator cuff tears in two orthogonal planes and always determine the distance of the tear from the long head of the bicipital tendon. Remember
Always compare both shoulders when applying the criteria for rotator cuff tears as a large side to side variation in size or echogenicity is suspicious for cuff pathology! Remember
Full thickness rotator cuff tears allow communication of the glenohumeral joint and the SA-SD bursa, while partial thickness tears do not. Minor Criteria for Rotator Cuff Tears
As stated earlier, along with the four major criteria for diagnosing rotator cuff tears, there are several minor criteria which also raise suspicion for rotator cuff disease. Minor Criteria for Rotator Cuff Tears
These include; either intra or extra-articular fluid collections, an abnormal contour of the subdeltoid bursa, and the position of the humeral head. All of these minor criteria have been
mentioned to some extent earlier, but let's spend a few minutes discussing each finding in a little more detail. Intra or Extra-articular Fluid Collections
While the presence of intraarticular fluid (i.e. joint effusion) is suspicious for co-existent rotator cuff disease, studies have shown that visualization of fluid in the subacromial subdeltoid bursa is an even more reliable finding for a rotator cuff tear. In fact, fluid in the subacromial subdeltoid bursa may be the only ultrasound finding in the presence of a small tear. Intra or Extra-articular Fluid Collections
The examiner must be careful not to apply excessive transducer pressure when scanning for bursal fluid, especially over the bony greater tuberosity, as small effusions may easily be displaced. Atlas demonstrates a small fluid collection within the subacromial subdeltoid bursa. Abnormal Contour of the Subdeltoid Bursa
As mentioned earlier, a normal shoulder demonstrates the bright linear echoes from the subdeltoid bursa in an arc pattern that is always convex upward. Concavity of the subdeltoid contour is often identified in the presence of medium and large rotator cuff tears, reflecting the absence of underlying cuff tendon. Abnormal Contour of the Subdeltoid Bursa
When the deltoid muscle contour is also involved, the ultrasound appearance is known as the deltoid herniation sign. Abnormal Contour of the Subdeltoid Bursa
In addition to an atypical subdeltoid bursal contour, you should also be aware of the thickness of the bursa itself. The normal SA-SD bursa measures 2 mm or less. When bursal thickening is evident, be on the lookout for a co-existent tear! Remember
The normal SA - SD bursa measures 2 mm or less. Elevation of the Humeral Head
In the presence of massive rotator cuff tears, the lack of cuff substance between the deltoid muscle and the humeral head provides a potential space for the humeral head to occupy.
Although it may not be obvious during real time scanning, comparison views of both shoulders will identify elevation of the affected humeral head in relation to the acromion process when compared with the normal side. This is another good reason to always perform side to side comparisons! X-rays of the shoulder are useful for confirming a suspected humeral head elevation.
Well, that's it for the most common shoulder pathology; rotator cuff tears. Let's move on and review a few of the less common findings. Calcific Tendinitis
This condition can be extremely painful and occurs when calcium crystals, or milk of calcium in its earlier state, deposits usually within the substance of the supraspinatus or biceps tendons. When present within the supraspinatus tendon, the calcifications are typically found within the critical zone. Calcific Tendinitis
Depending on the density of the calcium, acoustic shadowing may or may not be present are good examples of calcific tendinitis demonstrating the more advanced shadowing deposits. Calcific Tendinitis
Some physicians advocate the use of ultrasound-guided steroid injections to relieve patient symptoms, while other, more adventurous specialists may even attempt ultrasound guided removal of these deposits.
Biceps Tendinitis and Tenosynovitis
Patients presenting with either biceps tendinitis or tenosynovitis typically complain of pain over the anterolateral shoulder that radiates down the arm, especially with movement. Biceps Tendinitis and Tenosynovitis
Often affecting athletes or individuals who perform repetitive overhead arm movements like throwing, physical examination demonstrates point tenderness directly over the bicipital groove. Biceps Tendinitis and Tenosynovitis
These symptoms are secondary to inflammation of the long head of the biceps tendon (tendinitis) within the bicipital groove, or more advanced inflammation affecting both the biceps tendon and the tendon sheath (tenosynovitis). Biceps Tendinitis and Tenosynovitis
The ultrasound findings for the more advanced tenosynovitis differ from those for tendinitis. In addition to an enlarged, thickened, often hypoechoic tendon, seen in cases of tendinitis, a fluid collection is identified between the biceps tendon and its sheath in tenosynovitis. Biceps Tendinitis and Tenosynovitis
illustrate short and long axis views of an abnormal biceps tendon, demonstrating findings consistent with a diagnosis of tenosynovitis. Dislocation (Subluxation) of the Biceps Tendon
as we discuss dislocation and/or subluxation of the biceps tendon. Normally, the biceps tendon is anchored within the bicipital groove by the transverse humeral ligament, arising from the subscapularis and supraspinatus tendons, providing a roof to the bicipital groove. Dislocation (Subluxation) of the Biceps Tendon
show the normal appearance of this ligament. Any interruption to this ligament, whether secondary to trauma or other disorder, provides an opportunity for the biceps tendon to leave its normal position.
Dislocation (Subluxation) of the Biceps Tendon
As mentioned earlier, the medial side of the bicipital groove, formed by the lesser tuberosity of the humerus, with its relatively low, medial wall angle, provides an easier path for dislocation of the long head of the biceps tendon than does the
lateral side. Dislocation (Subluxation) of the Biceps Tendon
Therefore, dislocation or subluxation of the tendon is almost always over the lesser tuberosity, medially. Remember
Subluxation and/or dislocation of the long head of the biceps tendon almost always occurs over the medial wall of the bicipital groove. The difference between the two terms dislocation and subluxation is a matter of degree. A subluxed tendon is identified out of its normal position, riding up the medial wall or sitting atop the lesser tuberosity for example, while a dislocated tendon is displaced totally out of the groove. Demonstrates subluxation of the biceps tendon, which is seen overriding the lesser tuberosity of the humerus. This appearance is usually associated with a tear of the supraspinatus and/or subscapularis tendons, so don't stop looking until you identify one!
Biceps Tendon Tears and/or Rupture
Similar to the tendons of the rotator cuff, the biceps tendon is also subject to varying degrees and types of tearing. Biceps tendon tears may be intrasubstance, partial thickness tears or at the other end of the spectrum, full thickness tears and/or complete rupture of the tendon is also possible. Biceps Tendon Tears and/or Rupture
Provide us with short and long axis views of a complete rupture of the biceps tendon. In the short axis view, the bicipital groove contains a fluid filled synovial sheath that is somewhat thickened and heterogeneous. Biceps Tendon Tears and/or Rupture
The long axis view demonstrates the point at which the tendon ruptured (small arrow), more proximal than the location where the short axis view was taken (large arrow).
SA- SD Bursal Effusion and/or Bursitis
The largest and most commonly imaged bursa of the shoulder1 is the subacromial-subdeltoid (SA - SD) bursa, which acts as a buffer between the overlying acromion process, deltoid muscle and the rotator cuff. Normally seen as a pair of curvilinear echogenic lines hugging the surface of the rotator cuff, this potential space is typically echo free. SA- SD Bursal Effusion and/or Bursitis
illustrates a normal SA-SD bursa for us. The bursa can be seen as an echogenic interface (arrows) between the deltoid muscle and the rotator cuff when it is normal.
SA- SD Bursal Effusion and/or Bursitis
When an effusion is present, the first location to become fluid filled is a teardrop shaped thickening of the bursa distal to the lateral edge of the greater tuberosity, near the insertion of the supraspinatus tendon. A similar teardrop shaped bursal thickening can also be found posteriorly, along the deltoid shelf. SA- SD Bursal Effusion and/or Bursitis
When fluid filled, this appearance is known as the teardrop sign for obvious reasons nicely illustrates a teardrop shaped bursal effusion that was associated with a small tear of the supraspinatus tendon. SA- SD Bursal Effusion and/or Bursitis
Although bursal effusion may occur for many reasons, including trauma, arthritis, gout, or synovial disease, inflammation in the form of bursitis is quite common and the hypervascularity associated with the inflammation is often evident with colour flow Doppler. SA- SD Bursal Effusion and/or Bursitis
Chronic inflammation can be suspected when irregular bursal thickening is evident. provides us with a long axis view of a thickened, fluid filled, right SA -SD bursa. Note the irregular shape of the bursal walls (small arrow) and the considerable fluid collection (large arrow)
distending the bursa.
In fact, the SA - SD bursa is the 2nd largest bursa in the human body, after the iliopectineal bursa which we will discuss in the last module. Fracture - (Hill-Sachs Deformity)
Although not thought of as an effective tool for identifying bony abnormalities like fractures, ultrasound is very capable at identifying any discontinuity or irregularity of the cortical surface of bone. Fractures of the shoulder girdle are usually of the avulsion type, although depressed fractures from direct trauma can also be found. Fracture - (Hill-Sachs Deformity)
Avulsion fractures of the shoulder usually involve the greater tuberosity and less commonly the lesser tuberosity, at the insertion of the rotator cuff tendons. illustrates an avulsion fracture of the humeral head. Note the cortical interruption (small arrow) of the contour of the humeral head. Fracture - (Hill-Sachs Deformity)
is a good example of a depression fracture of the posterior humeral head (curved arrow) secondary to recurrent anterior dislocation (although it may occur after a single dislocation). Fracture - (Hill-Sachs Deformity)
This type of fracture is known as a Hill-Sachs deformity or defect. Diagram 2-23 below illustrates the correct transducer position, necessary to identify this particular type of fracture. It is best seen with the humerus internally rotated. Diagram 2-23 22 (with modifications)
The Hill-Sachs injury occurs as the posterior humeral head impacts against the anterior glenoid labrum during an anterior dislocation causing a depression fracture. On ultrasound, the humeral head at this location should be round, instead of the wedge shaped depression (curved arrow) Impingement Syndrome
Impingement of the rotator cuff occurs to some degree in
everyone's shoulder. Referring to Diagram 2-7 on page 2-9, recall that the space between the undersurface of the acromion and the superior aspect of the humeral head is normally quite narrow, but usually there is enough room between the acromion and the rotator cuff, so that the rotator cuff tendons slide easily underneath the acromion as the arm is raised. Impingement Syndrome
While any condition that further narrows this space can cause rotator cuff impingement, the normal action of raising the arm tends to force the humerus against the edge of the acromion resulting in momentary impingement of the cuff.
Impingement Syndrome
With overuse, this can cause irritation and swelling of the SA SD bursa as well as irritation or damage to the rotator cuff tendons. Further impingement can result from loss of competency of the rotator cuff. Seems like a never ending circle doesn't it? Impingement Syndrome
Here are a few more possible causes of shoulder impingement:
Impingement Syndrome
• congenital variations of the acromion size and shape (i.e. hooked acromion)
• loss of the rotator cuff, with superior migration of the humeral head Impingement Syndrome
• osteoarthritic spurs of the acromion or AC joint • capsular contracture and/or adhesive capsulitis (frozen shoulder) • thickened or calcified coracoacromial ligament
• thickened SA - SD bursa Impingement Syndrome
Now that we know what shoulder impingement is and what
causes it, let's take a look at a few possible complications outside the obvious pain and discomfort that patients experience. Impingement Syndrome
Impingement syndrome has been classified into three stages. Stage one generally occurs in patients less than 25 years of age and is frequently associated with an overuse injury, resulting in edema and/or hemorrhage within the rotator cuff and/or changes to the SA - SD bursa. Impingement Syndrome
Stage II is more advanced and tends to occur in patients 25 to 40 years of age. Rotator cuff changes which include fibrosis and bursal thickening may be seen. Impingement Syndrome
Finally, stage III generally occurs in patients over 50 years of age and frequently involves a partial or full thickness tear or tendon rupture as well as possible biceps tendon abnormalities. Impingement Syndrome
Treatment for shoulder impingement ranges from conservative therapy followed by strengthening exercises for the rotator cuff muscles in stage I, therapeutic shoulder injections in stage II and possible surgery for stage III. Miscellaneous Rotator Cuff Pathology
illustrates an ultrasound sign that was first described in the early 1980's during the performance of contrast arthrography of the shoulder. Miscellaneous Rotator Cuff Pathology
The "geyser sign" describes a situation in which contrast media leaks from the shoulder joint, through the rotator cuff, into the acromioclavicular joint during a contrast arthrogram of the shoulder. Miscellaneous Rotator Cuff Pathology
The presence of this sign suggests a large rotator cuff tear with erosion of the undersurface of the acromioclavicular joint. Miscellaneous Rotator Cuff Pathology
Well, that's it for our review of ultrasound of the shoulder. After you finish assignment two, we'll move on to the next module dealing with high resolution ultrasound of the foot and ankle. THANKS
