Wrist Joint Flashcards
function of the wrist joint
- To provide a mobile and stable foundation for hand
- Control length-tension for hand musculature
the upper extremity functions to
position the hand in space
joints of the wrist
radiocarpal & mid-carpal (functional)
arthrokinematics of radiocarpal
concave - convex rule
moves in the opposite direction
arthrokinematics of mid carpal joint
gliding
flexion ROM
85 deg
extension ROM
70-80 deg
ulnar deviation ROM
30-35 deg
radial deviation ROM
20-25 deg
radius and radioulnar disk make up the
triangular fibrocartilage
radioulnar disk lies between
the radius & ulna at the base of the ulna –> this is why there is no “ulnacarpal” joints
functionally, _______ contributes to both proximal & distal carpals
scaphoid
pisiform
proximal carpal
non-articular
increases the moment arm of FCU (b/c FCU is strung thru the pisiform)
sesamoid bone
carpals have ____ muscular attachments EXCEPT FOR -______
No;
pisiform & hamate
Only muscle crossing the radio carpal joint that attaches to the proximal row is:
flexor carpi ulnaris
attaches to pisiform, hamate & base of 5th metatarsal
lateral facet
46% articulation to scaphoid
medial facet
43% articulation to lunate
inferior disk
11% articulation to triquetrum (inferior ulnar disk)
triangular fibrocartilage complex TFCC
- continuous with the articular surface of the radius, covers the ulnar head and forms the articular surface on the ulnar side
- this is why you have more ulnar deviation than radial deviation —-> there isn’t as much bone limiting movement
- this is the soft spot on the posterior aspect of the wrist
the triangular fibrocartilage complex TFCC consists of
articular disk (triangular fibrocartilage), meniscus homologue, ulnocarpal (ulnar collateral) ligament, dorsal & volar radioulnar ligament, floor of ECU sheath
TFCC is the main stabilizer of:
distal radioulnar joint
TFCC acts as a buttress to support:
proximal carpal row
TFCC stabilizes the ulnar _____
head
TFCC contributes to the ______ stability
ulnarcarpal
TFCC distributes:
compressive loads
80% to radius
the TFCC excised increased loads on ____ from _____(%) to ____(%)
radius
80% to 94%
TFCC ______ congruency
increases
radiocarpal stability
loose, stong capsule reinforced by ligaments that extend to mid carpal joint
midcarpal joint occurs between
proximal row (triquetrium, lunate, scaphoid) & the distal row (trapezium, trapezoid, capitate, hamate)
midcarpal joint has
intercarpal joint capsule &
numerous ligaments
ligaments of the midcarpal joint
- provide primary stability and support
- guide motion
- transfer forces
the anterior wrist ligaments are more _______
complex
volar radiocarpal ligament
ANTERIOR WRIST LIGAMENT
***most important for motion & stability
can be divided into separate bands
bands of the volar radiocarpal ligament
radiolunate ligament
radiocapitate ligament
radiotriquetral ligament
radioscaphoid ligament
ulnocarpal ligament arises from
the TFCC
at the articular disk & base of the ulnar styloid
ulnocarpal ligament attaches to
triquetrum, capitate, & lunate carpals
Ulnocarpal ligament reinforces
the ulnar side of the wrist
ulnocarpal ligament is on the ___ side
anterior
volar radiocarpal ligament is on the _____ side
anterior
intercarpal ligament is on the _____ side
anterior
intercarpal ligaments prevent
diastasis of the carpals
diastasis- separation, pulling apart
intercarpal ligament connects _______ to ________ to help _______ the joint capsule
the dorsal proximal row of the carpals;
the distal row of the carpals;
strengthen
dorsal radiocarpal ligament is on the ____ side
posterior
dorsal radiocarpal ligament is a ________ ligament
extrinsic
dorsal radiocarpal ligaments attaches
from the posterior edge of the distal radius
to the scaphoid, triquetrum, lunate, and slips to the capitate
these ligaments are called - radiolunate, radiotriquetral, and radiocapitate ligaments
ulnar collateral ligaments attachment
POSTERIOR
ulna styloid process —> to the pisiform & triquetrum
radial collateral ligaments attachments
POSTERIOR
radial styloid process –> to the scaphoid, trapezium, to the 1st metacarpal
intrinsic ligaments of the posterior wrist
dorsal intercarpal
trapeziotrapezoid
trapeziocapitate
capitohamate
radiocarpal motion
gliding of convex proximal carpals over concave radius & disk
WRIST JOINT MOTION
- in flexion (moving towards neutral)
distal carpals glide in same direction on fixed proximal carpals
Wrist joint motion
- in neutral
scaphoid & capitate are closed packed
wrist joint motion
- in extension after neutral but BEFORE 45 degrees
combined distal carpals and scaphoid extending together
wrist joint motion
- in extension at 45 deg
scaphoid & lunate are closed packed
wrist joint motion
- in extension greater than 45 deg
carpals all glide on the radius & radioulnar (in the opposite direction)
wrist joint motion- in flexion - scaphoid does what?
contributes to both rows
reverse the extension sequence for flexion
radial deviation- the ____ row moves radially on the ____ until the carpals ____
distal;
proximal;
lock
radial deviation- at the end of the range, both rows moving as ____, until ulnar ligament is _____ & ______ impacts the radius
1;
taut;
scaphoid
radial deviation is predominant at the
midcarpal joint
ulnar deviation occurs predominantly as _________
radiocarpal motion
the maximum movement for radial deviation & ulnar deviation movement is at ________
neutral
wrist instability secondary to ligamentous disruption:
dorsal instability DISI
- maintained extension of lunate
- capitate flexion as compensation
- zig zag pattern
- usually secondary to dissociation between lunate and scaphoid
wrist instability secondary to ligamentous disruption:
volar instability VISI
- secondary to ligamentous disruption between lunate and triquetrium (lunate/scaphoid flex, triquetrum/distal row extend)
- normally the distal radius, lunate, capitate, and third metacarpal are colinear
which bone on the wrist is most susceptible to fracture?
scaphoid is susceptible to fracture
- poor healing properties secondary to poor vascular supply
