I.
Bursa around the shoulder (Fig1)
Awareness of location and extent of juxta-articular bursa is important in order to identify or exclude significant pathology.
Fig. 1: Bursa aorund the shoulder joint:
1. subacromial-subdeltoid bursa
2. Subscapularis bursa
3. Sucoracoid bursa
4. Coracoclavicular bursa
5. Supra-acromial bursa
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
1.
Subacromial-subdeltoid bursa
Location (Fig2)
..between the rotator cuff tendons and the coracoacromial arch
..between the rotator cuff tendons and the deltoid muscle
Fig. 2: Subacromial-subdeltoid bursa:
The SA-SD bursa extends between the acromion and corachacromial ligament superiorly, and the rotator cuff and rotator interval inferiorly, medially reaching the undersurface of the acromioclavicular joint.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Function
..Covers a large surface area and facilitates movement
Clinical significancy (Fig 3)
1) Rotator cuff tear
2) Inflammatory or crystal deposition disease
3) Septic bursitis
Fig. 3: Subacromial-subdeltoid bursa:
73 year-old male with partial thickness tear,articular side, anteror portion of supraspinatus tendon (red arrow). Oblique coronal FS T2 and oblique sagittal T2 WI MR images show subdeltoid - subacromial bursa effusion (green arrow heads).
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
2.
Subscapular bursa = superior subscapular recess
Location (Fig4):
..between the scapula and the subscapularis muscle,
and is located above and sometimes anterior to the subscapularis tendon
..between the superior and middle glenohumeral ligaments
Fig. 4: Subscapular bursa = superior subscapular recess:
The subscapular recess lies between the scapula and the subscapularis muscle, and is located above and sometimes anterior to the subscapularis tendon.
Fluid in the subscapular recess may be considered physiological, and is commonly found in association with non-specific glenohumeral joint effusions.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Almost always communicate with the glenohumeral joint
Fluid in the subscapular recess may be considered physiological,
and is commonly found in association with non-specific glenohumeral joint effusions.
(Fig 6,
7,
8,
9,
and 10)
3.
Subcoracoid bursa
Location (Fig11)
..Between the subscapularis tendon inferiorly,
and the coracoid process and the combined tendon of the short head of the biceps and the coracobrachialis muscle superiorly.
Fig. 11: Subcoracoid bursa:
The subcoracoid bursa (circles) lies between the subscapularis tendon inferiorly, and the coracoid process and the combined tendon of the short head of the biceps and the coracobrachialis muscle superiorly.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Function
Fasilitates movement by reducing friction between the subscapularis tendon and the tendons of the short head of the biceps and the coracobrachialis during the arc of rotation of the humeral head
Communication
..Not normally communicate with the glenohumeral joint
..May communicate with SA-SD bursa
** Clinical significance of an effusion in the subcoracoid bursa
1) Five of 11 patients had associated rotator cuff tear (Schraner and Major et al.
AJR 1999;172:1567-1571)
2) In five of 10 patients with rotatir internval tear,
CT arthrography revealed contrast medium anterior to the sibscapularis.
(Le Huec et al.
J Shoulder Elbow Surg 1996;5:41-46)
3) All patient with subcoracoid bursa effusions had evidence of rotator cuff tear (confirmed surgically in six patients) (Grainger et al.
AJR2000;174:1377-1380)
Anatomic evaluation reveals presence of separate subcoracoid bursa in nearly 90% of specimens.
Isolated or predominant subcoracoid effusions are considered abnormal,
and may refect subcoracoid bursitis.
(Fig12,
13,
14,
15,
and 16)
Fig. 16: Subcoracoid bursa:
73 year-old female with massive tear of supraspinatus tendon (red arrow) and infraspinatus tendon, associated severe atrophy in supra- & infra- spinatus muscle. There is underlying severe osteoarthritis with spur formation and capsular distension in acromioclavicular joint (green arrow). Note the subcoracoid bursa effusion (asterisk)
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
The subcoracoid burs ashould not be confused with the subscapularis bursa (=subscapularis recess)
4.
Subscapular bursa VS.
subcoracoid bursa (Fig17)
Two synovial-lined structures are located in the subcoracoid space anterior to the subscapularis but deep in relation to the coracoid process.
Because the superior subscapularis recess extends anterior to the subscapularis tendon,
fluid in this recess may mimic an effusion in the subcoracoid bursa.
The distinction between the two structures in of importance to radiologists because the causes of a subcoracoid bursa effusion may be different from the causes of a subscapularis recess effusion.
Fig. 17: Subscapular bursa VS. subcoracoid bursa:
The distinction between the two structures in of importance to radiologists because the causes of a subcoracoid bursa effusion may be different from the causes of a subscapularis recess effusion.
Fluid in the subcoracoid bursa represents a pathologic process, suc as bursitis, or results from communication with another fluid-containing structure.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Fluid in the subcoracoid bursa represents a pathologic process,
suc as bursitis,
or results from communication with another fluid-containing structure.
II.
Intramuscular cyst
= intramuscular ganglion cyst
Unilocular or multilocular rounded fluid collections located in the sheath or substance of one or more of the rotator cuff muscles but to not extend to either the articular or bursal surface.
Possible explanation for the association of intramuscular cyst with rotator cuff tears (Fig18)
1) Secondary to disruptions along the tendon attachments of the rotator cuff
2) Fluid from either the bursae or glenohumeral joint to enter the substance of the rotator cuff tendon and then track along the tendon fibers along the sheath or in the substance of the muscle
Fig. 18: Intramuscular cyst:
Possible explanation for the association of intramuscular cyst with rotator cuff tears, 1. Secondary to disruptions along the tendon attachments of the rotator cuff 2. Fluid from either the bursae or glenohumeral joint to enter the substance of the rotator cuff tendon and then track along the tendon fibers along the sheath or in the substance of the muscle
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Clinical significancy:
An association between intramuscular cysts and full-thickness and partial-thickness rotator cuff tears (Fig19,
20,
21,
22,
and 23)
Fig. 19: Intramuscular cyst – SST:
62 year-old male with right shoulder pain. Oblique coronal FS T2 MR image shows near full-thickness tear of supraspinatus tendon (red arrow). There is multiloculating intramuscular cysts (green arrow) in supraspinatus muscle. Mild atrophy of supraspinatus and infraspinatus muscles are also noted.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
III.
Fluid collection of the biceps tendon sheath
The biceps tendon sheath (Fig24)
: extension of the synovial lining of the shoulder à shoulder joint effusion tracking into the biceps tendon sheath
Increased fluid around the tendon : sign of tendinopathy (Fig25)
1) 1’ tendinopathy
2) 2’ tendinopathy :
90% of bicipital tendinopathy usually associated with disease of the rotator cuff and impingement synd.
Fig. 25: Fluid collection of the biceps tendon sheath associated with rotator cuff tear:
74 year-old male with full thickness tear of supraspinatus tendon (blue arrow).
See the retracted supraspinatus tendon (red arrow). There is moderated amount of glenohumeral joint effusion. Also noted fluid collection along the biceps tendon sheath (yellow arrow).
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
IV.
Paralabral cyst
= Paraglenoid labral cysts
Juxta-articular cystic lesions that usually show close relationship with the glenoid labrum.
The MRI appearance of paralabral cysts may vary from small unilocular to large multilocular juxta-articular cystic lesions.
** pathogenesis of paralabral cysts in unknown.
1.
Synovial cyst : lined by synovial cells and forms from evagination of the joint capsule or paraarticular bursa
2.
Ganglion cyst : may arise from a joint capsule,
bursa,
ligament,
tendon,
or subchondral bone
3.
Pseudocyst : may result from the extrusion of joint fluid through a labrocapsular tear into adjacent soft tissues
Evidence for supporting the relationship between paralabral cyst and labral tear
1.
Coincidence
2.
Proximity
3.
Tapered shaped of some cysts
Torn or avulsion of capsulolabral complex a through the tear,
synovial fluid can leak from the joint into paraarticular tissues causing the development of cysts (Fig26)
Fig. 26: Paralabral cyst:
That the principal cause of a paralabral cyst is an adjacent labral tear is supported by coincidence, proximity, and the tapered shaped of some cysts.
The prevailing theory is that these cysts may form after the capsulolabral complex is torn or avulsed. Through the tear, synovial fluid can leak from the joint into paraarticular tissues causing the development of cysts.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
As paralabral cysts are frequently found in association with labral tears or SLAP lesions,
it is postulated that labral tears induce a valve mechanism that finally generates a paralabral cyst.
(Fig27,
28,
29,
30,
31,
32,
and 33)
Fig. 27: Paralabral cyst:
32 year-old male. Axial FS T2 MR image demonstrates
SLAP type II with paralabral cyst (green arrow) in anterosuperior aspect of glenoid
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Fig. 28: Paralabral cyst:
59 year-old male. Axila and oblique coronal FS T2 MR images presented small ganglion cyst near posteroinferior labrum (green arrow). Possibility of associated labral tear was reported. On arthroscope, anterior labral degeneration was confirmed.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
** Relationship between paralabral cysts and glenoid labral tears
1) 20 patients with paralabral cysts had retrospective evidence of labral tears on MR imaging (Tirman et al.
Radiology 1994;190:653-658)
2) Superior labral tears on arthroscopy in 10 of 11 patients with paralabral cysts and suprascapular nerve entrapment (Moore et al.
J Shoulder Elbow Surg 1997;6:455-462)
3) 15(88%) of 17 patients with paralabral cysts on MR imaging had labral tears at arthroscopy (Fehrman et al.
Arthroscopy 1995;11:727-734)
4) 93% of cysts were located in the same quadrant as the labral tear (Glenn et al.
AJR 2000;174:1707-1715)
Ganglion cysts with entrapment neuropathy
Suprascapular nerve
Orgin : upper trunk (C5-6) of brachial plexus
Suprascapular neuropathy
Sx.
Chronic shoulder pain and weakness
Cause
: Stretching injury,
ligament abnormality,
fracture,
Overise or space occupying lesion such as Posterior paralabral cyst/ganglion
Suprascapular nerve enters supraspinous fossa through suprascapular notch,
passing under superior transverse scapular ligament.
It supplies two motor branches to supraspinatous muscle and courses around lateral edge of scapular spine.
Inferior transverse scapular ligament spans spinoglenoid notch,
and suprascapular nerve passes under it to enter infraspinous fossa.
Inferior branch of suprascapular nerve provides motor branches to infraspinatus muscle.
(Fig34)
Fig. 34: Ganglion cysts with entrapment neuropathy of suprascapular nerve:
Suprascapular nerve enters supraspinous fossa through suprascapular notch, passing under superior transverse scapular ligament. It supplies two motor branches to supraspinatous muscle and courses around lateral edge of scapular spine. Inferior transverse scapular ligament spans spinoglenoid notch, and suprascapular nerve passes under it to enter infraspinous fossa. Inferior branch of suprascapular nerve provides motor branches to infraspinatus muscle.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Paralabral cysts of the suprascapular or spinoglenoid notch may have clinical relevance by causing suprascapular nerve entrapment.
(Fig35,
36,
and 37)
Fig. 35: Ganglion cysts with entrapment neuropathy of suprascapular nerve:
Paralabral cysts of the suprascapular or spinoglenoid notch may have clinical relevance by causing suprascapular nerve entrapment.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Fig. 36: Ganglion cyst at suprascapular notch:
27 year-old male with right shoulder pain. EMG was demonstrated right suprascapular nerve neuropathy.
MRI images show lobulating contoured, septated cyst (asterisk) at the anteroinferior aspect of the supraspinatus muscle within the coracoacromial arch of the right shoulder, extension to the suprascapular notch and spinoglenoid fossa.
Mild atrophy of supraspinatus and infraspinatus muscle was suspected.
Ganglion cyst causing suprascapular nerve entrapment was diagnosed on MR.
Ganglion cyst was confirmed through excisional biopsy.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR
Fig. 37: Ganglion cyst at spinoglenoid notch:
34 year-old male with left shoulder pain.
Lobulating contoured multilobulated cyst (asterisk) is presented at left spinoglenoid notch.
Note increased signal intensity of infraspinatus muscle on T2WI, suggestive of suprascapular nerve entrapment.
Ganglion cyst was confirmed through excisional biopsy.
References: Radiology, Ulsan University Seoul Asan Hospital - Seoul/KR