wrist and hand Flashcards
what is the job of the wrist?
to fine tune hand position
what are the 3 parts of the distal ulna?
ulnar styloid process
fovea
pole
what 2 parts of the ulna are attachment sites for fibrocartilage?
the fovea and pole
t/f: the distal ulna is not in direct contact with the carpals
true
what forms the roof of the RC joint?
the TFCC
what is the function of the TFCC?
act as stabilizer at ulna
hold ulnar side of the wrist in place
what is the primary bone of the wrist?
the distal ulna
where is Lister’s tubercle and what does it do?
on the dorsal side of the hand
redirects the pull of the ECL
which is more distal, the radial or ulnar styloid process?
the radial styloid process
the radial styloid process is the attachment site for _____ _____ ligaments and the ulnar styloid process is the attachment sites for _____ _____ ligaments
radial collateral, ulnar collateral
what are the distal articulating RU joint surfaces?
the ulnar head and ulnar notch
what carpal bones does the distal radius articulate with?
the scaphoid and lunate
what is the most commonly fractured carpal bone?
scaphoid
what is the most frequently dislocated carpal bone?
lunate
what carpal bone occupies the central position?
capitate
what carpal bone provides the FCU attachment?
pisiform
what is unique about the hamate?
it has a hook feature
what are the most mobile carpal bones?
scaphoid, trapezium, lunate, and triquetrum
what carpal bone provides the axis for radial/ulnar deviation and flexion/extension at the wrist?
capitate
what 2 carpal bones make up the boundaries of the snuff box?
scaphoid and trapezium
what are the articulating surfaces of the radiocarpal jt?
concave distal radius and convex proximal carpals
what kind of joint is the RC jt?
ellipsoid-2DF
what are the actions at the RC jt?
flexion/extension
radial/ulnar deviation
t/f: the TFCC is at risk for damage
true
what is OPP of the RC jt?
0-20 deg flexion
what is the CPP of the RC jt?
full radiation deviation and extension
what is (+) ulnar variance?
longer ulna compared to radius; indicates TFCC injury
what is (-) ulnar variance?
shorter ulna compared to radius (normal)
what kind of joint is the midcarpal jt?
nonaxial gliding planar jt
what motions are allowed at the midcarpal jt?
wrist flexion/extension
radial/ulnar deviation
what are the jt surfaces of the midcarpal jt?
b/w the proximal and distal row of carpal bones
what do the intrinsics connect?
the carpal bones to each other
what do the extrinsics connect?
carpal bones to radius and ulna
are the TFCC structures part of the extrinsics or intrinsics?
extrinsics
what are the flexor and extensor retinaculums?
contain the tendons and sometimes nerves that go to fingers
what do the retinaculums create?
transverse carpal arch
what creates the carpal tunnel?
the transverse carpal ligament connecting the hook of the hamate and pisiform as well as the pisiform, trapezium, and scaphoid
during flexion at the wrist, where does the axis migrate?
distally
what is the end feel for wrist flexion?
firm
where does the axis migrate during wrist extension?
proximally
what is the end feel of wrist extension?
firm
what is the ML axis for wrist flexion/extension?
the capitate
what is the AP axis for radial/ulnar deviation?
the capitate
t/f: the scaphoid doesn’t move as much as the lunate
true
t/f: the largest amount of deviation comes from the distal row of carpals?
true
what is the end feel for radial deviation?
bony
what jts are responsible for radial deviation?
1/2 midcarpal
1/2 radiocarpal
what is the end feel for ulnar deviation?
firm
what jts are responsible for ulnar deviation?
1/3 midcarpal
2/3 radiocarpal
what are the arthrokinematics at the wrist during extension?
posterior roll
anterior glide
what are the arthrokinematics at the wrist during flexion?
anterior roll
posterior glide
what are the arthrokinematics at the wrist during radial deviation?
proximal carpals glide in ulnar direction
roll in radial direction
what are the arthrokinematics during ulnar deviation?
roll in ulnar direction
glide in radial direction
what is CPP at the wrist?
full extension
the distal row of carpals is ____ and the proximal row is ____
concave, convex
what are the thumb motions?
flexion/extension, abduction/adduction, opposition
what motion is allowed at the CMC joints of digits 2-5?
gliding
what digits are the stable pillars at the CMC?
2nd and 3rd
what digits have significant motion at the CMC?
4th and 5th
what is the function of the palmarly curved shafts of the metacarpals?
fit of objects in the hand
where is the volar plate located?
at the MCP and IP jts
where does the volar plate migrate during extension?
proximally
what is the role of the volar plate?
congruency and protection against hyperextension
is the collateral lig more lax with extension or flexion?
extension
is the collateral lig more tight with extension or flexion?
flexion
what part of the phalanges are bi-concave with 2 facets?
bases
what part of the phalanges are bi-condylar (convex)?
heads
how many phalanges does each digit have?
thumb-2
all other digits-3
what kind of jt is the MCP jt?
biaxial condyloid with 2 DF
what are the actions of the MCP jts?
flex/ex, abd/add
what are the jt surfaces of the MCP jts?
convex metacarpal heads
concave phalange bases
what kind of jt is the IP jt?
uniaxial with 1 DF
what actions do the IP jts allow?
flex/ex
how many IP joints do each digit have?
thumb-1
digits-2
what digit is the reference for abd/add?
the middle finger
when the MCPs are extended, the fingers can ____
abduct
when the MCPs are flexed, the fingers can _____
adduct
when you close your first, where do the fingers converge toward?
toward the scaphoid
what is the end feel at the MCPs for flex/ex?
firm
what is the CPP of the MCPs?
full MCP flexion
why is abduction allowed with with extension?
bc the collaterals become loose with extension
why is no abduction allowed with flexion?
bc the collaterals become tight with flexion
what ligament helps control the volar plate?
the accessory ligament
is the volar plate on the palmar or dorsal side?
palmer
what ligament attaches to volar plate and runs b/w the metacarpals heads?
the deep transverse ligament
what kind of jt in the MCP of the thumb?
hinge jt
what is the role of the sesamoid bones
dynamic rotation of the thumb segment
fine tuning grip
increased tendon leverage
what attaches to the radial sesamoid bone?
flexor pollicus brevis and adductor pollicus brevis
what attaches to the ulnar sesamoid bone?
adductor pollicus brevis
what kind of jts are the DIPs and PIPs?
hinge jts with 1 DF
what are the supporting structures of the IP jts?
jt capsule, collateral ligs, volar plate
what does the deep transverse metacarpal ligament attach to?
the metacarpal heads
what is the OPP of the MCP and IPs?
20 deg flexion ???
what is the tendinous system?
3 bands/tendons of the extensor
1 central band and 2 lateral bands on either side
what is the retinacular system?
thickened fascia holding tendons in place
what are the flexor pulleys?
palmar fascia and annular ligaments
what is the palmar fascia?
instrinsic- triangular structure in the palm that covers the underlying neurovascular structures, tendons, and ligaments
what do the annular ligaments do?
maintain tendons w/in their positions during flexion
what is vow stringing?
strong contraction causing tendon to be pulled away from the jt axis of rotation
what allows for function of the hand?
synergistic activity of the wrist and finger functions
what happens when you close your fist?
finger flexion with wrist extension and finger adduction
what happens when you open your fist?
finger extension with wrist flexion and finger abduction
what is a power grip?
more extrinsic force with less emphasis on precision
what is the non-prehensile grip/hook?
holding a bag without the thumb use
what are the prehensile grips?
cylinder
sphere
fist
what is the cylinder grip?
grabbing a water bottle
what is the sphere grip?
holding a ball
what is the fist grip?
holding a thinner object like a hammer
what are the precision grips?
lateral pinching, 3 prong chuck, and tip to tip grips
what are the power grips?
non-prehensile (hook) and prehensile (cylinder, sphere, and fist) grips
what is a precision grip?
intrinsic controls for precision and less force
what is the lateral pinch grip?
key pinch
pad of thumb along the lateral aspect of the index finger
what is the 3 prong chuck grip?
holding a pen
thumb opposing index and middle finger
what is the tip to tip grip?
holding a USB
thumb and index finger pads facing each other
power grip
gross grasp
partially flexed fingers and counterpressure from the thumb
finger flexion w/wrist stabilized in extension
optimal wrist: 20-30 deg ext with slight ulnar deviation
significantly weakened with wrist flexion
precision grip
accuracy and refinement
object manipulation
uses thumb and one or more digits to improve grip security or to add variable amounts of force
grip strength is ____ times greater in males
2
grip strength is ___ % stronger on the dominant hand
6
what is the sensory innervation of the hand?
superficial branches of the median, ulnar, and radial nerves
SC segments C5-T1
what does the radial nerve innervate?
wrist extensors
what does the median nerve innervate?
most wrist flexors (not FCU)
what does the ulnar nerve innervate?
most small muscles in the hand (not FDP or thenar muscles)
what does radial injury result in?
wrist drop
what does median injury result in?
hand of benediction
inability to oppose
finger cant go into flexion
paralyzed thenar muscles
what does ulnar injury result in?
claw hand
injury in 4th and 5th digits
paralyzed intrinsics
what is the intrinsic plus position?
MCP flexion with IP extension
shortest interossei and lumbrical position
contracture of intrinsic muscles
what is the intrinsic minus position?
MCP extension with IP flexion
paralysis of interossei and lumbricals
“claw hand”
