MSK

Question 1

What is the biceps anchor?

Answer 1

origin of the long head of the biceps tendon at the superior labrum

Question 2

What is the rotator interval?

Answer 2

space between the supraspinatus tendon and subscapularis tendon, seen well on sag oblique

Question 3

When does the magic angle phenomenon occur?

Answer 3

when collagen fibers are oriented at about 55 deg to the constant magnetic induction field (results in intermediate signal on short TE sequences such as T1, PD, and GR (T2*) images

Question 4

What and where is the critical zone?

Answer 4

hypovascular region of the tendon where magic angle phenomenon commonly occurs in the shoulder - about 1 cm proximal to the insertion of the supraspinatus tendon

Question 5

Where is the critical zone?

Answer 5

1-1.5 cm proximal to the tendon insertion. Tears at this location are not as common as previously believed.

Question 6

How do we differentiate magic angle from an abnormal tendon?

Answer 6

Use long TE sequences, such as T2. Signal changes in magic angle are not assoc w/ thinning, thickening, or irregularity of the tendon.

Question 7

Other causes of increased signal in normal supra tendon besides magic angle?

Answer 7

-connective tissue b/n tendon fascicles

Question 8

Causes of shoulder impingement syndrome

Answer 8

1. abnormal config of the anterior acromion / acromial shape of type III: inferiorly projecting hook

Question 9

Causes of shoulder impingement syndrome

Answer 9

2. anterior downsloping of the acromion (sag) - can be eval on sag and cor oblique - anterior acromion is more caudal than posterior acromion

Question 10

Causes of shoulder impingement syndrome

Answer 10

3. low-lying acromion (coronal)

Question 11

Causes of shoulder impingement syndrome

Answer 11

4. inferolateral tilt/slope of the acromion (coronal) - most lateral portion of acromion is tilted inferiorly relative to the clavicle

Question 12

Causes of shoulder impingement syndrome

Answer 12

5. os acromiale

Question 13

Causes of shoulder impingement syndrome

Answer 13

6. AC DJD

Question 14

Causes of shoulder impingement syndrome

Answer 14

7. thick coracoacromial ligament - has never been shown to be related to impingement

Question 15

Causes of shoulder impingement syndrome

Answer 15

8. post-traumatic osseous deformity

Question 16

Causes of shoulder impingement syndrome

Answer 16

9. instability

Question 17

Causes of shoulder impingement syndrome

Answer 17

10. muscle overdevelopment - weightlifters, swimmers, and other athlethes - deformity of superior surface of supraspinatus muscle caused by AC joint may be the only abnormality

Question 18

3 predominant shapes of the acromion based on scapular Y-view radiographs by Bigliani and colleagues

Answer 18

type I - flat undersurface

Question 19

Which acromion types were thought to have an increased incidence of cuff pathology?

Answer 19

type II and III (not borne out in practice -> acromion type no longer considered important in relation to cuff pathology)

Question 20

Up to what age does the os acromiale normally fuse?

Answer 20

25 yo

Question 21

On what view is the os acromiale best idenfitied?

Answer 21

axial

Question 22

On what MR images are biceps tendon subluxation and dislocation shown best?

Answer 22

axial

Question 23

Tears of the subscapularis tendon are best evaluated on what MR images?

Answer 23

axial or sag

Question 24

Where is Hill-Sachs defect seen best?

Answer 24

2 most superior axial images (below coracoid process, posterior flatting of humerus is normal)

Question 25

Bankart fracture?

Answer 25

axial and sag

Question 26

What is the sensi and speci for fill-thickness rotator cuff tears by MRI?

Answer 26

> 90%

Question 27

Acute tears of the long head of the biceps unrelated to impingement generally occur where?

Answer 27

distally, near the musculotendinous junction

Question 28

What does GIRD mean?

Answer 28

glenohumeral internal rotational deficit aka posterosuperior impingement

Question 29

What causes subcoracoid impingement?

Answer 29

narrowing of the space between tip of coracoid process and the humerus - may be congenital or due to coracoid fracture or surgery

Question 30

Where is atrophy usually localized in the subscapularis, which may be an accessory sign for tear?

Answer 30

cranial aspect

Question 31

What are the borders or margins of the rotator interval?

Answer 31

anterior: coracohumeral ligament, superior glenohumeral ligament, and capsule

Question 32

What are the borders or margins of the rotator interval?

Answer 32

superior: supraspinatus tendon

Question 33

What are the borders or margins of the rotator interval?

Answer 33

inferior: subscapularis tendon

Question 34

What are the borders or margins of the rotator interval?

Answer 34

medial: coracoid process - base of the triangle

Question 35

What are the borders or margins of the rotator interval?

Answer 35

lateral: transverse humeral ligament - apex - roof of bicipital groove

Question 36

Causes of rotator interval tears?

Answer 36

anterior glenohumeral dislocations or glenohumeral instability, or surgical defect from arthro

Question 37

What are the different types of instabilities?

Answer 37

1. anterior (nearly 95%)

Question 38

What are the different types of instabilities?

Answer 38

2. posterior

Question 39

What are the different types of instabilities?

Answer 39

3. multidirectional

Question 40

What are the different types of instabilities?

Answer 40

4. superior - generally is assoc w/ multidirectional

Question 41

Which of the types of instabilities account for most of the other 5%?

Answer 41

Posterior and multidirectional

Question 42

What is glenoid dysplasia?

Answer 42

congenital deficiency of the depth and radius of curvature of the glenoid fossa - may predispose to instability; increased incidence of posterior labral tears or detachments because of absence of the bony posterior lip of inferior glenoid, w/c is replaced by labral tissue that is easily injured

Question 43

Where does the joint capsule attach laterally? medially?

Answer 43

laterally on the anatomic neck of the humerus; medially, usually to the labrum or to the adjacent periosteum of the glenoid; *posterior capsule attaches directly on the posterior glenoid labrum

Question 44

3 types of anterior capsule insertions

Answer 44

type I - medial attachment on or very near the labrum

Question 45

3 glenohumeral ligaments

Answer 45

1. superior - level of the body of the coracoid process; prevents inferior displacement of humerus when abducted

Question 46

4 glenohumeral ligaments

Answer 46

2. middle - lies deep to suscap tendon and adj to the anterior labrum (can mimic torn labral fragment); contributes to anterior stability

Question 47

5 glenohumeral ligaments

Answer 47

3. inferior - main stabilizing ligament of the shoulder

Question 48

What are the normal variants of the labrum?

Answer 48

-sublabral recess - presence of synovial recess/sulcus interposed between glenoid rim and labrum; undercutting of articular cartilage between the labrum and glenoid cortex; undercutting of the normal redundancy of the superior labrum (mimic superior labral tear)

Question 49

What are the normal variants of the labrum?

Answer 49

-sublabral foramen - labral detachment from the glenoid / detached anterosuperior labrum; labrum attaches to the glenoid at the mid-portion (vs avulsed labrum - will not reattach at this point)

Question 50

What are the normal variants of the labrum?

Answer 50

-Buford complex - congenital absence of the anterosuperior labrum; assoc w/ markedly thickened middle glenohumeral ligament

Question 51

What are the normal variants of the labrum?

Answer 51

*Detachment of the labrum from the glenoid at any site other than the superior or anterosuperior glenoid is a true abnormality.

Question 52

What are the glenoid labral tears w/ underlying instability?

Answer 52

Bankart and ALPSA

Question 53

What are the noninstability labral lesions?

Answer 53

SLAP, labral cysts, and GLAD

Question 54

4 types of SLAP lesions

Answer 54

type I - fraying of the free edge of the superior glenoid labrum

Question 55

5 types of SLAP lesions

Answer 55

type II - detachment of superior labrum from the glenoid

Question 56

6 types of SLAP lesions

Answer 56

type III - bucket-handle tear of the superior labrum w/o involvement of long head

Question 57

7 types of SLAP lesions

Answer 57

type IV - bucket-handle tear of the labrum extending into the long head

Question 58

Intermediate signal in the tendon after rotator cuff surgery may represent what?

Answer 58

degen, postop granulation tissue, or partial tear

Question 59

When are rotator cuff tears massive?

Answer 59

when there are tears of >1 of the rotator cuff tendons

Question 60

What is the superior and anterior border of the subcoracoid bursa?

Answer 60

coracoid process and the attached combined tendon of the short head of the biceps and the coracobrachialis

Question 61

As the suprascapular nerve courses through the suprascapular notch, it provides motor innervation to what muscles?

Answer 61

supra and infra

Question 62

As the suprascapular nerve extends distally into the spinoglenoid notch, it provides motor innervation to?

Answer 62

infra only

Question 63

What nerve and artery run through the quadrilateral space?

Answer 63

axillary nerve (teres minor atrophy), posterior humeral circumflex artery

Question 64

Borders of the quadrilateral space?

Answer 64

lateral: humerus

Question 65

Borders of the quadrilateral space?

Answer 65

medial: long head of the triceps

Question 66

Borders of the quadrilateral space?

Answer 66

superior: teres minor

Question 67

Borders of the quadrilateral space?

Answer 67

inferior: teres major

Question 68

Where are the pain and paresthesias felt in quadrilateral space syndrome?

Answer 68

lateral aspect of the shoulder and the posterosuperior region of the arm

Question 69

What are the nerves that have been reported to be involved in Pasonage-Turner?

Answer 69

suprascapular - supra and infra

Question 70

What are the nerves that have been reported to be involved in Pasonage-Turner?

Answer 70

axillary - teres minor and deltoid

Question 71

What are the nerves that have been reported to be involved in Pasonage-Turner?

Answer 71

subscapular - subscapularis

Question 72

What are the nerves that have been reported to be involved in Pasonage-Turner?

Answer 72

long thoracic - serratus anterior

Question 73

What is post-traumatic osteolysis of the clavicle?

Answer 73

bone resorption of the distal end of the clavicle after a single episode of severe trauma, or it may occur from repetitive trauma

Question 74

How are facet joints classified according to mobility?

Answer 74

diarthrodial / freely movable

Question 75

How are cartilaginous articulations formed by the intervertebral disks classified according to mobility?

Answer 75

amphiarthrodial / minimally movable

Question 76

What are the inner and outer portions of the annulus fibrosus made of?

Answer 76

inner - fibrocartilage; outer - concentrically oriented lamellae of collagen fibers

Question 77

T/F? Distinction between the nucleus pulposus and inner annulus fibrosus is best done by MRI.

Answer 77

FALSE

Question 78

T/F? Diffuse extension beyond the margins by 1-2 mm may occur in some histologically normal disks.

Answer 78

TRUE

Question 79

T/F? Posterior margins of disks tend to be mildly concave in the upper lumbar spine, straight at the L4-L5 level, and slightly convex at the LS junction.

Answer 79

TRUE

Question 80

Among the 3 types of annular tears, which is the only type of practical interest?

Answer 80

radial

Question 81

What level do radial tears usually occur?

Answer 81

L4-5 and L5-S1

Question 82

How do annular tears appear on contrast T1?

Answer 82

high signal

Question 83

-mild?

Answer 83

anterior epidural fat is not obliterated

Question 84

-moderate?

Answer 84

epidural fat is obliterated and thecal sac is displaced

Question 85

-severe?

Answer 85

cord is being effaced or nerve roots displaced

Question 86

What is a conjoined nerve?

Answer 86

2 nerve roots exiting the thecal sac at the same location. (They can be seen within dilated CSF space, and the lateral recess on the side of the conjoined nerve root is enlarged, indicating that this is a long-standing process)

Question 87

What are the Modic types?

Answer 87

type 1 - inflammatory tissue — low high enhance

Question 88

What are the Modic types?

Answer 88

type 2 - focal conversion to fat — high iso to high

Question 89

What are the Modic types?

Answer 89

type 3 - sclerosis low —- t1 low t2

Question 90

Expected postop changes

Answer 90

-no marrow enhancement (unless Modic 1 changes are present)

Question 91

Expected postop changes

Answer 91

-nerve roots - may enhance for 6 months

Question 92

Expected postop changes

Answer 92

-epidural - peripheral enhancement of fibrosis (may mimic extrusion) in first 6 months; diffuse enhancement after 6 months; enhancement of fibrosis for years

Question 93

Expected postop changes

Answer 93

-disks - enhancement of posterior annulus and increased T2 signal for years - as a result of curettage

Question 94

Expected postop changes

Answer 94

-mass effect from scarring at the operated disk level may take months to resolve and may never resolve

Question 95

What is a pseudomeningocele?

Answer 95

defect in the dura w/ a leak of spinal fluid

Question 96

What are complications of spinal surgery?

Answer 96

a) spondylodiskitis and epidural abscess

Question 97

What are complications of spinal surgery?

Answer 97

b) epidural hematoma

Question 98

What are complications of spinal surgery?

Answer 98

c) failure of fusion of bone graft material

Question 99

What are complications of spinal surgery?

Answer 99

d) arachnoiditis

Question 100

What are complications of spinal surgery?

Answer 100

e) defect in the dural sac that creates a pseudomeningocele

Question 101

Besides the enhancement, what are other signs that may hep distinguish epidural fibrosis from a disk abnormality?

Answer 101

may not be contiguous w/ the adjacent disk; instead of producing a mass effect on the dural sac, it may cause retraction

Question 102

Infections of the spine generally occurs from?

Answer 102

hematogeneous spread of Staph aureus from a distant site

Question 103

In adults, what is usually affected first in spondylodiskitis?

Answer 103

marrow in the region of a vertebral body end plate (osteomyelitis or spondylitis)

Question 104

In children, what is usually affected first in spondylodiskitis?

Answer 104

disk - disks in children are more vascular

Question 105

What consist the triad of MRI findings in spondylodiskitis?

Answer 105

1. low T1 in the marrow of adjacent vertebral bodies

Question 106

What consist the triad of MRI findings in spondylodiskitis?

Answer 106

2. enhancement of marrow, and possibly of the disk if an abscess has not formed

Question 107

What consist the triad of MRI findings in spondylodiskitis?

Answer 107

3. high T2 disk signal