1

Wrist instability:MR findings without clinical significance

Hiroshi Yoshioka

Department of RadiologyBrigham and Women’s Hospital

Outline

• Triangular fibrocartilage complex (TFCC)• Lunotriquetral ligament (LTL)• Scapholunate ligament (SLL)• Extensor tendons

Ulnotriquetral ligamentExtensor carpi ulnaris tendon sheath

Meniscus homologue

Ulnar collateral ligament

Triangular ligament(lower lamina)

Triangular ligament(upper lamina)

Disc proper(Articular disc)

Ulnolunate ligament

TFCC anatomy

Ligamentum subcruentum

Normal TFCC using a microscopy coil

Disc proper

Meniscus homologue

Triangularligament

Ulnotriquetral ligament

Volar radioulnar ligament

Dorsal radioulnar ligament

Triangular ligament Degenerative change of TFCC

GRE PDWI

2

Central perforation of disc TFCC signal intensity changes

0# of TFCC signal change in one subject

0

1

2

3

4

5

6

7

8 Patients with TFCC injuriesVolunteers

1 2 3 4 5 6

#

0

2

4

6

8

Patient

Volunteer

One abnormal signal within TFCCn=23

*

Radial attachment

UTLDisc Ulnarattachment

PRULDRUL

* p<0.05

Ulnar variance vs TFCC

level of the lunate fossa

level of the ulnar head

Plus variance Zero variance Minus variance

Ulnar variance vs TFCCTFCC

UlnarRadius

TFCC thickness TFCC angle

TFCC thickness and angle

3

Ulnar variannce vs TFCC thickness

0

0.5

1

1.5

2

2.5

3

3.5

-6 -4 -2 0 2 4 6

Ulnar variance (mm)

TFC

C t

hic

kness

(m

m)

patients

volunteers

Ulnar variance vs TFCC thickness

Yoshioka et al. JMRI 2007; 26:714-719

Ulnar variance vs TFCC angle

-10

0

10

20

30

40

50

60

-6 -4 -2 0 2 4 6

Ulnar variance (mm)

TFC

C a

ngl

e (

degr

ees

)

patients

volunteers

Ulnar variance vs TFCC angle

Yoshioka et al. JMRI 2007; 26:714-719

LTL anatomy – 3 regions -

• V-shaped (20 mm in length)

DORSAL VOLAR

Dorsal zone:Ligamentous,highly important functionally, particularly as a restraint to rotation

Proximal zone: fibrocartilaginous, the weakest, close approximation to the TFCC

Volar zone:Ligamentous,the strongest and thickest

Lunate

LTL – axial imagesDorsal zone (striated)

Volar zone (striated, thicker)

Radiolunotriquetral ligament

L TS

Lunotriquetral ligament (signal intensity)Type 1 Type 2 Type 3

Lunate

Triquetral

Lunotriquetral ligament (shape)

Regular triangle(1) Broad-based triangle(2)

Asymmetrical triangle(4)

Narrow-based triangle(3)

Bar shape(5)

4

Ulnar – radial deviated positonin MRI

Ulnar-deviated position Radial-deviated position

Ulnar – neutral - radial deviated position

Ulnar-deviated position Neutral positon Radial-deviated position

SLL anatomy – 3 regions -

• Horseshoe-shaped or C-shaped (18 mm in length and 2-3 mm in thickness)

Lunate

DORSAL VOLAR

Dorsal zone:ligamentousthe strongest

Proximal zone: fibrocartilaginous,the weakest, undergoes degenerative perforation

Volar zone:Ligamentous,less easily observed on MRI

SLL – axial imagesDorsal zone (thick and homogeneous low intensity)

Volar zone (inhomogeneous striated structure)

SL

SLL shape• Totterman SM, Miller RJ. Radiology 1996; 200:237-241

Lunate

Bandlike dorsal portion Triangle middle portion

Scaphoid

Trapezoidal volar portionDORSAL VOLAR

SLL variation?

5

Extensor tendons- supination vs pronation -

pronationsupination

UlnaRadius

Ext.carp.uln.

extensor minimi digiti

Morphological changes of TFCC:Supination – Pronation (axial)

pronationsupination

Morphological changes of TFCC:Supination – Pronation (coronal)

pronationsupination

pronationsupination

Extensor minimi digiti

Diameter of 5th extensor tendon compartment

0

1

2

3

4

mm

/m

m

** * * * * * **

-7.5mm -6mm -4.5mm -3mm -1.5mm 0 mm 1.5mm 3mm 4,5mm 6mm

pronation supinationNormalpronation

OApronation

Normalsupination

OAsupination

ruptured tendon (Extensor minimi digiti)

OA patient with tendon rupture