The Wrist Complex Flashcards
what two compound joints make up the wrist complex?
radiocarpal
midcarpal
The wrist complex contributes to ________ relationship in multiarticular hand muscles and also what?
The wrist complex contributes to length tension relationship in multiarticular hand muscles and also FINE ADJUSTMENT OF GRIP
structure and biomechanics of wrist/hand are the same from person to person (true or false)
false: vary from person to person
subtle variations cause differences in way function occurs
wrist complex is a ____ joint with ____ degrees of freedom
biaxial joint with 2 degrees of freedom
flexion/extension
radial and ulnar deviation
what wrist motions occur in the coronal axis?
flexion and extension
in the coronal axis, wrist flexion is __ to ___ degrees
65-85 degrees of flexion
in the coronal axis, wrist extension is ___ to ___ degrees
60-85 degrees of extension
is there more degrees flexion or extension in the wrist?
More flexion (65-85 compared to extension: 60-85) ((in EEO, wrist flexion is 80, extension is 70))
volar/palmar refers to what wrist motion?
flexion
dorsal/dorsum refers to what wrist motion?
extension
radiocarpal joint is formed by ___ and ____ proximally and ___, _____, ____ distally
proximal radiocarpal joint: radius and TFCC
distal radiocarpal joint: scaphoid, lunate, triquetrum
proximal radiocarpal joint segment:
The lateral radial facet articulates with the _____
scaphoid
proximal segment: the medial radial facet articulates with the _____
lunate
Proximal segment: the TFCC articulates with the _______
triquetrum
How is the radius angled at the radiocarpal joint?
oblique and angled volarly in the sagittal plane/ulnarly in the frontal plane
TFCC connects medially via ____ and ____ ligaments
TFCC connects medially via dorsal and volar radioulnar ligaments
TFCC connects distally to what four things?
ECU tendon
triquetrum
hamate
base of 5th metacarpal
In the radiocarpal joint, the proximal carpal row includes what 3 carpals?
scaphoid, lunate, and triquetrum
The proximal carpal row is connected by what interosseous ligaments?
scapholunate interosseous ligament and lunotriquetral interosseous ligament
The pisiform does not support the radius!
Works as a sesamoid bone to increase the moment arm for which tendon?
Flexor Carpi Ulnaris (FCU)
The _____ radiocarpal segment is sharper than the _____ radiocarpal segment (proximal vs. distal)
distal radiocarpal segment is sharper than the proximal segment, making an INCONGRUENT JOINT
The scaphoid and lunate receive ____% of the axial load of the wrist
80%
The TFCC receives ___% of the axial load of the wrist
20% of the wrist load
Is the dorsal radius slightly longer than the volar radius?
YES (tilted volarly)
An ulna negative variance means length of the ulna is ____
short
radiocarpal joint incongruence and angle of proximal joint surface results in greater range of ____ than _____ (extension/flexion) and radiocarpal _____ deviation (ulnar/radial)
greater flexion than extension, greater ulnar deviation than radial deviation
ulnar positive variance means distal ulnar length is _____ compared to radius
long ulna
ulnar positive variance is associated with
radial fracture (may surgically use ulnar shortening to decrease pain)
ulnar negative variance is associated with what?
avascular necrosis of lunate (keinböcks disease)
*due to abnormal force distribution and thicker TFCC
ulnar positive variance is often accompanied by ____ impingement
TFCC impingement between distal ulna and triquetrum (thinner TFCC)
what muscle crosses the radiocarpal joint but does not contribute to the stability of the midcarpal joint?
FCU: attaches to the pisiform, hook of hamate, base of 5th metacarpal
most ligaments and muscles crossing radiocarpal joint also contribute to the stability of the midcarpal joint (true or false)
true except FCU
The excursions of the midcarpal joint generally favor range of ____ over ____ (extension vs flexion) and ____ deviation over ____ deviation (radial vs ulnar)
midcarpal: extension over flexion, radial deviation over ulnar deviation, which is opposite of radiocarpal joint
What is the midcarpal joint structure?
Articulation between scaphoid, lunate, triquetrum proximally and trapezium, trapezoid, capitate, hamate distally
Is the midcarpal joint concave-convex or convex-concave?
CONCAVE-CONVEX
true or false: the midcarpals move almost as a fixed unit, with equal distribution of loads across articulations with proximal row
true
Are the dorsal or volar ligaments thicker in the wrist?
volar ligaments: thicker and stronger
dorsal ligaments: thinner
extrinsic ligaments connect the _____ to the radius or ulna proximally or to the metacarpals distally
extrinsic ligaments: carpals to the radius/ulna or to the metacarpals
intrinsic wrist ligaments connect the ____ to themselves
carpals
intrinsic ligaments are also known as intercarpal or interosseous ligaments
true or false: intrinsic ligaments are stronger and less likely to fail but have a slower healing time than extrinsic ligaments
true (book, 276)
what are the 3 bands of the volar radiocarpal ligament?
-radioscaphocapitate/radiocapitate
-radiolunate/radiolunotriquetral
-radioscapholunate
what does capitate, the keystone of the wrist carpal bones, touch?
2, 3, 4 metacarpals, lunate, trapezoid, scaphoid, hamate
What 3 structures are part of the ulnocarpal ligament complex?
TFCC, ulnolunate ligament, unar collateral ligament
what are the extrinsic volar carpal ligaments?
volar radiocarpal ligaments, radial collateral ligament, ulnocarpal ligament compelx
what are the intrinsic volar carpal ligaments and what do they do?
scapholunate interosseous ligament-maintain scapho-lunate stability
lunotriquetral interosseous ligament-maintain lunate-triquetral stability
v-deltoid
what are the dorsal carpal ligaments?
dorsal radiocarpal ligament (to triquetrum)
dorsal intercarpal ligament-horizontal from triquetrum, lunate, scaphoid and trapezium
what do the dorsal carpal ligaments do?
form horizontal V to stabilize scaphoid during wrist ROM
become tight in wrist flexion
