Bony structures Radius

• Ulna (configuration, no shortening)

• Carpal bones (proximal and distal rows)

• Metacarpals

• Radiocarpal angle (see below)

— Shape and position (see below)

• Metacarpals and phalanges:

— Five digital rays

— Normal bone marrow signal

• Articular surfaces, especially of radiocarpal and carpometacarpal joints:

• Normal cortical thickness

• No marginal osteophytes

• No subchondral signal changes

• Normal width of joint space (see below)

Ligamentous structures

Carpal tunnel

Median nerve

Ulnar nerve

Soft tissues

Ulnar (triangular) disk:

— Configuration (see below)

— Internal structure (hypointense expansion to styloid attachment and to radial end of ulna with central rarefaction)

— No signal abnormalities

— No discontinuities

Interosseous ligaments: scapholunate and luna-totriquetral ligaments and ligaments of the distal row of carpal bones

— Signal intensity

— Contours (smooth, intact) Extrinsic ligaments:

— Signal intensity

— Contours (smooth, intact) Width (see below)

Tendons (tendon sheaths in six compartments, thickness, position, symmetry)

Flexor retinaculum (no palmar convexity)

No circumscribed widening of tendons

No thickening of tendon sheath walls

No increase of fluid in tendon compartment

No fluid-filled cyst

No ganglion

Course

Width

No impingement, especially in the carpal tunnel (axial image)

No diffuse or circumscribed swelling (e.g., common at level of pisiform bone) No narrowing (e.g., common at level of hamate bone)

No signal changes

Width

Course

No expansion No bony impingement No subcutaneous nodules

Coronal image
Coronal image

Important Data

1

Radiocarpal angle:

a Coronal: 10-30°

b Lateral: 10-15°

2

Ulnar (triangular) disk or triangular fibrocartilage complex

(TFC):

• Maximum thickness: 1.6 cm ± 0.5 cm

3

Inclination of lunate bone relative to long axis (lateral view):

• 0-30°

4

Inclination of scaphoid bone relative to long axis (sagittal

view):

• 30-60°

5 Joint spaces:

a Distal radioulnar joint: ca. 3 mm

b Other joints: ca. 2 mm

s

Distal radioulnar length relation:

• 1-5 mm

• >5 mm = ulnar shortening

• <1 mm = ulnar lengthening

7

Lines are drawn tangent to the corners of the radial ulnar

notch and to the base points of the roughly triangular cross

section of the distal ulna. Lines are drawn perpendicular to

these tangents, and the angle between them is measured:

• In neutral position +15° - +45°, in supination approx.

+ 100°. Always compare with the opposite side.

Axial image at level of distal radioulnar joint
Sagittal image
Sagittal image

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