Muscles covering the shoulder joint especially the deltoid Lungs soft tissues

Size congruent with humeral head

Smooth articular surface

Cortex (thickness, no discontinuities)

No osteophytes

No subchondral erosion

Bone marrow signal

Articular cartilage

Glenoid labrum is triangular about its whole circumference and is firmly attached to the glenoid. (Caution: variant often seen in the anterosupe-rior quadrant should not be mistaken for a tear!) Normal development of the acromion (straight, curved, hook-shaped, upslope angle—see below) and clavicle Smooth, sharp margins Normal bone-marrow signal Configuration Width (see below) No hypertrophy Normal subacromial fat layer Subacromial bursa is not fluid-filled, fat stripe of bursa is visible and undisplaced Configuration Position

Course (over humeral head) Homogeneous signal intensity of tendon No hyperintense signal (on T2-weighted images) No peritendinous fluid

Long tendon segment runs in bicipital groove

Hypointense

No discontinuities

Normal width

No increase of fluid in long biceps tendon sheath

No fluid in other bursae (especially the subcora-

coid and subdeltoid)

Shape

Position

Signal intensity

Important Data

1

Glenoid angle:

• Approx. 5° of retroversion (i.e., angle between the glenoid

and a perpendicular to the scapular long axis is slightly

open posteriorly, but the range of variation is large)

2

Joint space:

• Shoulder joint: < 6 mm

3

Acromioclavicular joint:

• Width < 1 cm

4

Angle of acromion upslope (oblique sagittal image plane):

• 10-40°

5

Diameter of biceps tendon:

• Approximately 4-6 mm

S

Bicipital groove:

• Width: 7-9 mm

• Depth: 4-7 mm

The bicipital groove starts at least 20 mm below the tip of the

humeral head. (This differentiates the groove from a Hill-Sachs

lesion, which often occurs at a higher level.)

Axial image

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Axial image

Paracoronal image parallel to the supraspinatus muscle
Parasagittal image at right angles to the supraspinatus muscle

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