Hand Flashcards
which parts of the radius are concave?
M-L and A-P
where is lister’s tubercle?
radius
degree of ulnar tilt of radius
25º
degree of palmar tilt of radius
10º
the difference between lengths of radius and ulna
ulnar variance
when is ulnar difference value deemed abnormal?
when >1 mm difference
pronation = functional __________ of radius
shortening
supination = functional _________ of radius
lengthening
ulnar positive/negative
+: ulna is longer than radius
-: distal ulna is shorter than radius
most unstable carpal bone
lunate
sesamoid bone of hand
pisiform
largest carpal bone
capitate
this carpal bone articulates with the 1st MC
trapezium
this carpal bone articulates with the 2nd MC
trapezoid
describe the shape and components of carpal tunnel in respect to carpal bones/ligs
palmar concavity of carpal bones + transverse carpal lig
components of radiocarpal joint
concave radius/articular disc, convex scaphoid and lunate
components of medial midcarpal joint
convex capitate/hamate
concave scaphoid/lunate/triquetrum
components of lateral midcarpal joint
concave trapezium/trapezoid
convex scaphoid
two main roles of hand ligs
- maintain alignment
2. disperse forces
wrist extension occurs with this movement
radial deviation
wrist flexion occurs with this movement
ulnar deviation
AOR of wrist
capitate
explain the central column
simplified model for arthrokinematics
radius - lunate - capitate - third MC
entire midcarpal joint represented by what happens between….
lunate and capitate
entire radiocarpal joint represented by the movement between…
lunate and radius
arthrokin at radiocarpal joint
convex carpal on concave radius
roll and glide in opposite direction in open chain
movement at midcarpal joint is considered as….
one unit
in respect to arthrokin, a segment moves and rolls in the ____ direction
same
secondary extensors have a critical role in…
positioning wrist for grip
long finger flexors create these two movements
finger flexion + wrist flexion
max effort grip wrist extension angle
30º
which deviators are stronger?
radial
3 functions of hand
- sensory
- effector
- emotional communicator
define ray
one MC bone and its associated phalanges
hand is _____ on palmar side. why?
concave - allows tendons to reside here
1st MC rotated __________
90º medially
1st MC positioned ______
anterior
1st MC orientation allows for…
thumb positioning for prehension
arches of the hand
- prox transverse arch
- distal transverse arch
- longitudinal arch
term for main source of structural stability of arch of hand
keystone
keystone structure of prox transverse arch
capitate
prox transverse arch is formed by….
distal row of carpals
what kind of arch is the prox transverse arch?
rigid
distal transverse arch is formed by…
MCP joints
keystone structure of distal transverse arch
2 and 3 MCPS
where is the distal transverse arch flexible?
1, 4, 5 MCPs
longitudinal arch follows general shape of…
2nd and 3rd rays
long arch provides…
longitudinal stability
keystone structure of longitudinal arch
2/3 MCPs
discuss mobility/stability of CMC 2-5
2+3: stable
4+5: mobile
the 4th and 5th CMC joints are responsible for….
cupping motion of flexion and internal rotation
describe 1st CMC joint capsule
loose to allow movement
what kind of joint is the 1st CMC?
saddle
describe shape of trapezium in relation to arthrokin at 1st CMC
concave palmar-dorsal
convex med-lat
arthrokin of flex/ext and ab/add at 1st CMC
flex/ext: concave on convex
add/ab: convex on concave
close packed position of 1st CMC
opposition
composite motion of thumb opposition
abduction, flexion, internal rotation
arthrokin of MCP joint
convex metacarpals and concave proximal phalanges
two things imbedded in MCP capsule
- rad/uln collateral ligs
2. palmar plate
form tunnels to house the finger flexor tendons and anchor to palmar plate
fibrous digital sheaths
MCP joint has large degree of….
passive accessory motions
MCP joint flexion - where do you have more?
5th MCP
most movement in thumb comes from this joint
CMC
IP arthrokin
concave distal base on convex proximal head
roll/glide in same direction
ligs that restrict extension at IP
check-rein(deer) ligaments
close packed position of IP
full extension
as we age, we get more __________ of the thumb IP joint
extension
extrinsic muscles have proximal attachments on….
forearm or humeral epis
intrinsic muscles have prox and distal attachments……
within the hand
sole flexor of the thumb
FPL - flexes MCP and CMC
hold tendons close to joint to prevent bowstringing and maintain length-tension relationship
flexor pulleys
what kind of tendons are in the fibrous digital sheaths?
extrinsic
provide lube and nutrients for tendons to pass through
digital synovial sheath
isolating PIP flexion requires….
stabilization from proximal extensors
most dominant extensor
ED
ED isolated contraction =
MCP hyperextension
“backbone” of extensor mechanism
central band
diverge from central band
lateral bands
forms a sling around the base of proximal phalanx
dorsal hood
purpose of extensor mechanism
transmit extensor forces + stabilize its tendons
these are essential for fine motor control
intrinsics
intrinsic plus position
lumbrical grip
extreinsic plus position
MCP extension and IP flexion
two types of manipulation that the hand produces as an effector organ
repetitive
blunt
5 types of grip (review pics of these in slide 50)
- power grip
- precision grip
- power (key) pinch
- precision pinch
- hook grip
RA reduces…
tensile strength of CT
cause of zigzag deformity in thumb
taut FPL –> hyperext of MCP –> dislocated CMC
swan-neck deformity vs boutonniere deformity
swan-neck ends in DIP flexion, BD ends in DIP extension
ulnar drift
overstretching of RCL - ulnar dev at MCP joint
cause of swan neck
contracted intrinsic muscles + taught FDP
cause of boutonnieres
slipped lateral band, overstretched palmar plate, ruptured central band