Learning objectives
To understand the complex anatomy of the wrist,
with special attention to those involved on the 'intercalated segmet' of the wrist kynematics,
such as the scapholunate and lunotriquetral ligaments.
To recognize and describe the radiological findings of carpal / wrist instability.
To review and ilustrate the spectrum of X-ray and MRI findings in carpal instability
Background
Carpal instability is a biomechanical alteration refered to the loss of ability of the wrist to maintain a normal balance between the carpal bones under physiologic movements,
losing joint congruency as a result.
The forms secondary to traumas are the most frequent; as trauma causes ligamentous injuries that lead to misalignments of the joint surfaces,
or badly healed fractures with consequent articular incongruency.
Carpal instability due to the deposition of microcrystals caused by chronic inflammation processes (rheumatoid arthritis),
metabolic (chondrocalcinosis and gout),
and congenital diseases...
Findings and procedure details
ANATOMY
Osseous anatomy
The wrist is a complex joint formed by 20 interdependent articulations binding 15 bones: radius and ulna,
eight carpal bones,
and the bases of 5 metacarpals.
Anatomically and functionally,
these bones are divided into proximal and distal rows:
- The distal carpal row consists of 4 tightly bound bones with little mobility between them: From radial to ulnar,
the trapezium,
trapezoid,
capitate,
and hamate.
- The proximal carpal row formed by the scaphoid,
lunate,
triquetrum and pisiform exhibits substantial intercarpal mobility.
The...
Conclusion
- Knowledge of the complex anatomic structures that comprise the wristis crucial in proper assessment and diagnosis of carpal instability.
- MR imaging has become the modality of choice in the assessment of wrist pathology,
providing high resolution anatomic details and multi-planar imaging capabilities useful in the evaluation of soft tissue structures such as ligaments.
- However,
X-ray imaging stillplays an important role in the detection of carpal instability.
References
Freeland,
A.
E.,
& Geissler,
W.
B.
(2015).
Kinematics and pathophysiology of carpal instability.
InWrist and Elbow Arthroscopy(pp.
101-118).
Springer New York.
Kani,
K.
K.,
Mulcahy,
H.,
& Chew,
F.
S.
(2016).
Understanding carpal instability: a radiographic perspective.Skeletal radiology,
1-13.
Trail,
I.
A.
(2015).
Acute Carpal Instability.
InDisorders of the Hand(pp.
367-378).
Springer London.
Garcia-Elias,
M.
(2015).
Chronic Carpal Instability.
InDisorders of the Hand(pp.
179-193).
Springer London.
Schmitt,
R.,
Froehner,
S.,
Coblenz,
G.,
& Christopoulos,
G.
(2006).
Carpal instability.European radiology,16(10),
2161-2178.
Wolfe,
S.
W.,
Garcia-Elias,...