Wrist and Hand Flashcards
list the carpal bones in the proximal row (M-L)
pisiform, triquetrum, lunate, scaphoid
list the carpal bones in the distal row (M-L)
hamate, capitate, trapezoid, trapezium
how many degrees of freedom are at the humeroulnar articulation?
1
why is there only 1 df at the humeroulnar joint?
so that muscles that originate on the distal humerus have more stability to allow for distal mobility
what is the main weight bearing joint fixed in closed chain of the wrist and hand?
the radiocarpal joint
what type of relationship do the “working end” of levers have?
inverse relationship
the radius expansion at carpus is primarily for?
weight bearing
the ulna expansion at the humerus is primarily for?
site of muscle attachment
the ulna expansion at carpus is modified for radius and hand to rotate creating a space called…
ulnocarpal space with triangular fibrocartilage
what is the central column/pillar effect?
think of a bridge the center is the most stable and keep the bridge standing without it it would fall. In the hand think of the lunate and capitate so CMC 3 is most stable
what drives motion in the hand around central column?
thenar and hypothenar
what two planes does biaxial motion occur in?
frontal and saggital
what plane does flexion and extension of the wrist occur in?
saggital plane about an M-L axis
what is the normal range for wrist flexion?
80-90º
what is the normal range for wrist extension?
70-80º
what plane does radial and ulnar deviation occur in?
frontal plane about an A-P axis
what is the normal range for radial deviation?
20-25º
what is the normal range for ulnar deviation?
30-35º
what is something that is a restricter to radial deviation?
radial styloid
what articulates proximally at the radiocarpal joint?
radius and radioulnar disk/TF
what articulates distally at the radiocarpal joint?
scaphoid, lunate and triquetrum
what carpal bone articulates with the lateral radial facet of the radiocarpal joint?
scaphoid
what carpal bone articulates with the medial radial facet of the radiocarpal joint?
lunate
what carpal bone articulates with the inferior radial facet of the radiocarpal joint?
triquetrum
T/F there is no formal carpal articulation with the ulna
true
the proximal carpal row forms what surface?
a single biconcave surface (scaphoid and lunate together)
what does the biconcave surface do?
alters shape to accommodate forearm and hand position
which proximal bone is not included in the proximal row of carpals?
the pisiform
what is the function of the pisiform?
it is a sesamoid bone, functions to increase MA
T/F muscles act directly on the RC joint
false no muscles act directly on the RC joint
how is motion created at the Rc joint if no muscles act directly on it?
ligamentous forces distributed and muscles that insert at the distal carpals and metacarpals create motion
is flexion or extension greater at the radiocarpal joint?
flexion
is ulnar deviation or radial deviation greater at the radiocarpal joint?
ulnar deviation
what results in ROM contribution differences at the radiocarpal joint?
proximal RC incongruence and angulation
what is the midcarpal joint?
the joints between the distal and proximal row of carpals with no isolated capsule, interrupted multiarticular surface
how many degrees of freedom are at the midcarpal joint?
2
what type of joint is the midcarpal joint?
condyloid
is flexion or extension greater at the midcarpal joint?
extension
is radial deviation or ulnar deviation greater at the midcarpal joint?
radial deviation
what are the intercarpal joints?
articulations between all of the carpal bones
what does the intercarpal joints allow for?
minimal movement to accommodate hand and wrist positioning
the intercapal joints are bound together by many ligaments.. what does this do for the joint?
it means there is little give allotted
which side is more mobile at the intercarpal joints (ulnar or radial) and why?
ulnar side is more mobile bc there is a bigger gap between the ulnar styloid and the carpal bones then the radial styloid and carpal bones
which ligament is stronger? the palmar ligament or the dorsal ligament
palmar ligaments
what is the most common carpal bone dislocated?
the lunate
which way does the lunate dislocate and why?
palmarly bc there is a weakened area palmarly near the lunate making it unstable
the proximal pole of the scaphoid has no ligament attachment dorsally which causes the formation of…
ganglion cyst
describe the dorsal radiocarpal ligament
thickening of capsule
lunate and radius contact
check rein to end range wrist flexion
what is the radial collateral ligament a check rein to?
ulnar deviation
what is the ulnar collateral ligament a check rein to?
radial deviation
describe the volar (palmar) radiocarpal ligament
it is the most important of all ligaments for stability and passive mobility contribution
3 distinct bands all intracapsular
on average 85º of wrist flexion is expected. what does the RC and MC joint contribute?
50% from RC
35% from MC
on average 85º of wrist extension is expected. what does the RC and MC joint contribute?
35% from RC
50% from MC
what are the coupled motions at the wrist?
flexion and ulnar deviation
extension and radial deviation
which styloid process (radial or ulnar) projects more distally?
radial
what is the ulnar tilt angle?
25º (bc the radial styloid process projects further than the ulnar)
at the radiocarpal what is moving on what?
CONVEX carpals moving on a CONCAVE radius
review: if it is concave moving on convex is roll and slide opposite or same direction?
same direction
review: if it is convex moving on concave is roll and slide opposite or same direction?
opposite directions
with wrist flexion at the radiocarpal joints what is the roll and slide?
palmar roll and dorsal slide
with wrist extension at the radiocarpal joints what is the roll and slide?
dorsal roll and palmar slide
with radial deviation at the radiocarpal joints what is the roll and slide?
radial roll and ulnar slide
with ulnar deviation at the radiocarpal joints what is the roll and slide?
ulnar roll and radial glide
what are some check rein structures to radial deviation?
ulnar collateral ligament, and bony articulation (radial styloid process into carpals)
what is the closed pack position for the radiocarpal joint?
full extension so palmar and intercarpal ligaments become taut
with wrist flexion does the scaphoid flex or extend?
flexes (remember scaphoid aka navicular sails in the direction of intended motion)
with wrist flexion which way do the lunate and triquetrum go?
they both extend
when the scaphoid follows the intended motion and the lunate and triquetrum go the opposite direction this creates counter rotation which…
increases ligamentous tension and increase co adaptation of midcarpal articular surfaces to increase stability
what are the two halves of the midcarpal joint?
ulnar 1/2 and radial 1/2
ulnar side of midcarpal joint arthrokinematics in frontal and sagittal planes?
CONVEX hamate and capitate moving on CONCAVE lunate and triquetrum
radial side of midcarpal joint arthrokinematics in frontal and saggital planes?
CONCAVE trapezius and trapezoid moving on CONVEX scaphoid
is the ulnar side of the midcarpal joint linked anatomically, functionally, or both with the radiocarpal joint and why?
both due to same convex/concave orientation
is the radial side of the midcarpal joint linked anatomically, functionally, or both with the radiocarpal joint and why?
only anatomically because opposite concave/convex orientation
describe radial deviation at the wrist of carpals?
the distal row of carpals roll toward RD with proximal row until the ligaments and bones create limitation and approximation
how do specific carpal bones move in radial deviation?
scaphoid and lunate move palmarly and then the trapezius and trapezoid move dorsally
why do some of the carpal bones move anteriorly or palmarly and some move posteriorly or dorsally in radial deviation
allows freedom of motion would have half the ROM without this. Coupling motion accommodates narrowing space
in radial deviation are the RC and MC joints closed or open pack?
closed pack
describe ulnar deviation at the wrist of carpals
distal row of carpals rolls toward UD with the proximal row until ligaments and bones create limitation and approximation
how do specific carpal bones move in ulnar deviation?
the scaphoid and lunate move dorsally while the trapezius and trapezoid move palmarly
why do some of the carpal bones move anteriorly or palmarly and some move posteriorly or dorsally in ulnar deviation
the opposite directions of movement accommodates full ROM
what is the closed pack position of the wrist?
approximately 45º wrist extension and slight radial deviation
what is the open pack position of the wrist?
slight flexion with slight ulnar deviation
what are some primary wrist flexors?
palmaris longus, flexor carpi radialis, and flexor carpi ulnaris
which is a more effective deviator FCU or FCR?
FCU because its more proximal insertion
is FCU a spurt or shunt muscle?
spurt
which carpal bone increases the MA of FCU?
pisiform
what are some digit flexors with secondary wrist action?
FDS, FDP, and FPL
which functions better as a wrist flexor FDS or FDP and why?
FDS because it inserts more proximally
what two motions can FDL contribute to?
flexion of the wrist and RD because it crosses the wrist on the ulnar side and it is lateral
what are some primary wrist extensors?
ECRL, ECRB, and ECU
which is more effective ECRB and ECRL and why?
ECRL due to central insertion at MCP 3
what are some digit extensors with secondary wrist action?
ED, EI, EDM, EPL, EPB, and APL
name the muscle synergies (there’s 6)
- ECR(L or B) and ED
- FCU and ADM
- ECU and EP(L or B)
- wrist and finger flexion
- FCU and ECU
- FCR and ECR
what is the muscle synergy between ECR(L or B) and ED?
weak ECR leads to wrist extension combined with finger extension due to ED compensation
what is the muscle synergy between FCU and ADM?
ADM originates on pisiform, FCU contraction stabilizes pisiform to allow abduction of 5th digit, “proximal stability leads to distal mobility”
what is the muscle synergy between ECU and EP(L or B)?
during thumb extension ECU maintains the hand in neutral position and avoids radial deviation
what is the muscle synergy between wrist and finger flexion?
extend wrist, fingers flex. flex wrist, fingers extend
(minimizes active and passive insufficiency by slacking the muscle)
what is tenodesis?
minimal active wrist extension= adaptive shortening of finger flexors
increased passive tension= increased ADL function
series of parallel elastic components advantage to produce “tension or force”
what do we do with tenodesis?
use the stiffness to your advantage
gravity flexes wrist to allow hand to open. passive tension in the wrist extensors opens the hand. active extension by ECRB creates passive tension in the flexors to grasp object
what do we not do with tenodesis?
DONT stretch out finger flexors
what is the muscle synergy between FCU and ECU?
allows for pure ulnar deviation if both equally firing
if FCU is > than ECU what will we see?
flexion and ulnar deviation
if ECU is > than FCU what will we see?
extension and ulnar deviation
what types of joint are the CMC 2-4?
plane synovial
how many degrees of freedom are at CMC joints 2-4?
1
what motions occur at CMC joints 2-4?
flexion and extension
what are the arthrokinematics at CMC joints 2-5?
concave on convex
flexion- anterior roll anterior glide
extension- posterior roll posterior glide
what type of joint is CMC 5?
condyloid/saddle
how many degrees of freedom are at CMC 5?
2
what motions occur at CMC 5?
flexion/extension and abduction/adduction
what type of joint is CMC 1?
saddle biaxial joint between trapezium and 1st metacarpal
in which plane is the trapezium concave at CMC 1?
sagittal plane
what are the arthrokinematics in the sagittal plane for CMC 1?
convex MC on concave TP
abduction- palmar roll and dorsal glide
adduction- dorsal roll and palmar glide
in which plane is the trapezium convex at CMC 1?
frontal plane
what are the arthrokinematics in the frontal plane for CMC 1?
concave MC on convex TP
flexion- medial roll medial glide
extension- lateral roll lateral glide
how much flexion do we typically see at CMC 1?
15-20º
how much extension do we typically see at CMC 1?
20-30º
how much abduction do we typically see at CMC 1?
70º
what type of joint do we see at MCP 2-5?
condyloid joint
how many degrees of freedom do we see at MCP 2-5?
2
what motions do we see at MCP 2-5?
flexion and extension
abduction and adduction
are MCP 2-5 convex on concave or concave on convex?
concave on convex
what action is difficult in the closed pack position of MCP 2-5?
abduction and adduction
what is taut in flexion of MCP 2-5?
collateral ligament and capsule
what is the open pack position of MCP 2-5?
neutral to slight flexion
does flexion ROM increase from thumb to pinky or pinky to thumb?
thumb to pinky about 90º to 110º
what is extension ROM of MCP 2-5?
30-40º AROM
>90º PROM
what is abduction/adduction ROM of MCP 2-5?
30-40º(increases with extension bc open pack position)
what type of joint is MCP 1?
condyloid
how many degrees of freedom are at MCP 1
2
what motions occur at MCP 1
flexion/extension and abduction/adduction
why do CMC and MCP have synergistic action?
to allow 5º of freedom for opposition
what type of joints are the PIP and DIPs?
synovial hinge
how many degrees of freedom are at the PIP and DIPs?
1
are the PIPs and DIPs concave on convex or convex on concave?
concave on convex
From 2-5 or 5-2 which way does ROM increase?
2-5
what is the ROM at PIP and DIP 2?
PIP 100-110º DIP 80º
what is the ROM at PIP and DIP 5?
PIP 135º DIP 90º
what is a power grip?
stability grip, large forces are necessary, no need for precision, object is usually spherical or cylindric
ex) holding a water bottle or hammer
what is a precision grip?
contour needed of an object, delicate actions necessary
ex) holding a baseball or egg
what is a power pinch?
aka key pinch. grabbing an object between the thumb and lateral border of index finger. large forces used
ex) holding a key
what are the two precision pinches?
tip to top and pad to pad
what is a precision pinch?
fine control between index and thumb without power
when do we use tip to tip compared to pad to pad
depends on what you’re grabbing and which you use and whats more comfortable
what is a hook grip?
the thumb is not involved, partial flexion of PIP and DIP joints. static nature grip (isometric), low forces, over long periods time (endurance required). flexor digitorum profundus primarily active
ex) bucket handle
what is Swan neck deformity generally from?
RA and or synovitis
what is occurirng with swan neck deformity?
increases flexor pull on MCP joint, decreases ligament integrity. results in MCP flexion, PIP extension, DIP flexion
what occurs with Boutonniere deformity?
MCP extension, PIP flexion, DIP extension
what is the functional hand position?
wrist extension 20º, ulnar deviation 10º, MCP flexion 45º, PIP flexion 30º, and slight DIP flexion
what does the functional hand position optimize?
finger flexor force (length-tension).
all wrist muscles are under equal tension
how do we pick a position of immobilization?
depends on the disability
common immobilization position is?
the functional position (wrist extension 20º, ulnar deviation 10º, MCP flexion 45º, PIP flexion 30º, and slight DIP flexion) with DECREASED wrist extension (<20º) increased MCP flexion (around 70º) IP joints neutral, thumb- CMC wide abduction MCP slight flexion IP neutral
why do we use the common immobilization position?
to minimize potential for contracture (adaptive shortening)
