Finger Joints and Ligaments Flashcards
how is the hand a multi-purpose organ
manipulate things in our environment
use it to interact with our environment
sensory organ
what is the primary goal of treating the hand
restoration of function
can the hand function w/o the brain
no
but the brain needs the hand as a primary tool of expression
carpometacarpal joints of the fingers (CMC joints)
digits 2-5
articulation b/w the distal carpal row and bases of 2nd-5th metacarpals
2nd metacarpal articulates with
primarily the trapezoid
secondarily with the trapezium, capitate and 3rd metacarpal
3rd metacarpal articulates with
primarily with capitate
secondarily w/ second and fourth metacarpals
4th metacarpal articulates with
primarily w/ capitate and hamate
also with 3rd and 5th metacarpals
5th metacarpal articulates w/
primarily w/ the hamate
also w/ ulnar side of the 4th metacarpal
what kind of joints are the 2-4th CMC joints
plane synovial joints
have slightly curved articular surfaces
1 degree of freedom
what motion do the CMC joints allow
potentially allow flexion/extension in sagittal plane around a frontal axis
normal ROM flexion/extension CMC joint
ranges up to 10-20 degrees
increases as you go from radial to ulnar side
what kind of joint is the 5th CMC joint
saddle joint with 2 degrees of freedom
what movements does the 5th CMC joint allow
flexion/extension
ABD/ADD
some rotation
flexion/extension 5th CMC joint
10-20 degrees
motion increases as you go from radial to ulnar side
are you ever going to measure CMC motion
no
what ligaments support all CMC joints
supported by strong transverse and weaker longitudinal ligaments volary and dorsally
transverse metacarpal ligament (CMC)
tethers together the heads of the four metacarpals of the fingers
prevents CMC ABD
what predominately controls ROM at CMC joints
ligamentous structure
what happens from radial to ulnar side
ROM increases
2nd and 3rd joints are essentially immobile
4th is more mobile
5th is most mobile
stability of the 2nd and 3rd CMC joints
functional adaptation
enhances the function of the radial wrist flexors and extensors
MORE EFFICIENT
what happens since there are muscles that insert on the bases of the 2nd and 3rd metacarpals
when they contract
they would act initially on the CMC joints before flexing or extending the midcarpal or radiocarpal joints
since the CMC joints are immobile
it allows the muscles to have a more distal attachment, functionally
leads to an increased lever arm
leads to greater efficiency for wrist extensors and flexors
joint capsule for CMC joint
continuous w/ that of the intermetacarpal joints
primary function of CMC joint
contribute to hollowing of the palm
form arches of the hand
which joints creates the palm/hollows the hand
4/5th CMC joints
how many arches in the palm
4
3 structural and 1 functional
structural arches
transverse carpal arch
transverse metacarpal arch
longitudinal arch
transverse carpal arch
most proximal arch
is a consistent concavity
created by the curved shapes of the carpals and by the ligaments that maintain concavity
this arch forms the carpal tunnel
ligaments that maintain concavity
intercarpal ligaments
transverse carpal ligament
flexor retinaculum
transverse metacarpal arch
formed by heads of the metacarpals
4th and 5th metacarpal heads move towards the 2nd and 3rd via the CMC joint
longitudinal arch
formed by each finger with respective carpal, metacarpal and phalanges
functional arch
oblique arch
oblique arch
formed by the thumb with each finger in opposition
4 of them
what do the arches of the hand allow
palm and fingers to conform to objects being held
bones form the arches of the hand
intrinsic muscles maintain the integrity of the arches
what happens if the hand looks flat
muscle issue
wasting of intrinsic muscles
metacarpophalangeal joints (MCP, MP)
each MCP joint is composed of a convex metacarpal head articulating with the concave base of the proximal phalanx
Concave moving on convex
everything in the same direction
what kind of joints are the MCP joints
condyloid joints with 2 degrees of freedom
what motions do MCP joints allow
flexion/extension
ABD/ADD
flexion/extension MCP
sagittal plane around a frontal axis
motion will vary from radial side to ulnar side (more ROM on ulnar side)
MCP flexion
90 degrees (radial side)
135 degrees (ulnar side)
MCP extension
45 degrees beyond neutral
ABD/ADD MCP
frontal plane around a sagittal axis
most motion is at the index finger
ABD/ADD ROM MCP
45 degrees both ways
middle finger MCP ABD/ADD
radial ABD and ulnar ABD
what is ABD/ADD MCP ROM referred to as
normal arc of motion
total ABD + total ADD
for each finger
ligaments of MCP joint
transverse metacarpal ligament
radial and ulnar collateral ligaments
accessory collateral ligaments
transverse metacarpal ligament
runs on volar aspect and attaches one metacarpal tot he next via the volar plates
radial and ulnar collateral ligaments
run obliquely from the dorsal aspect of the metacarpal to ventral aspect of the base of the proximal phalanx
are taut in MP flexion and slack in extension
accessory collateral ligaments
run from dorsal aspect of metacarpal to the volar plate
slack in flexion
joint capsule (MCP)
surrounds the joint
relatively loose and is reinforced dorsally by the extensor expansion
lines by synovial membrane
slack in extension which allows for some axial rotation
volar plate
MCP articulation w/in the sagittal plane d/t incongruency
volar plate reduces the incongruency and make MCP joint more congruent in the sagittal plane
what is the volar plate
fibrocartilage that is firmly attached to the base of the proximal phalanx
blends with the more superficial transverse metacarpal ligament
volar plate function
increases the articular surfaces in the sagittal plane
prevent pinching of the flexor tendons
restrict hypertension
how is the volar plate stabilized
by attachments of the accessory collateral ligaments
accessory movements of MCP joint
great deal of joint play at MCP joint
A-P glides
M-L glides
large amount of distraction available
interphalangeal joints of the fingers and thumb
a convex head articulating with the concave base
concave moving on convex
bone motion, roll and glide in the same direction
how many types of IP joints are there
3
DIP, PIP, IP
what kind of joints are the IP joints
synovial hinge joint
one degree of freedom
what motion does the IP joint allow
flexion/extension
sagittal plane around a frontal axis
pip joint flexion ROM
90-135 degrees
increasing as you go towards the ulnar side
why is full PIP joint flexion important
hand function
extension of PIP joint
0 degrees
beyond 0 is hyperextension
DIP joint flexion ROM
0-70 or 90 degrees
DIP joint extension ROM
active –> 0 degrees
passive –> up to 30 degrees
ligaments of IP joints
collateral ligaments
collateral ligaments IP joint
insert on the proximal phalanges
remain taut in all positions
joint capsule IP joint
relatively loose
helps maintain integrity of the joint
reinforced by the presence of the volar plate
volar plate of IP joint
reinforced each of the capsules
structurally and functionally identical to the ones at the MCP joints
NOT CONNECTED BY A TRANSVERSE LIG
accessory movements of IP joint
rotation
distraction
rotation @ IP joints
positions pads of fingers in an optimal position to oppose the thumb
distraction at IP joints
M-L and A-P glides from external forces
what accessory movement is mostly @DIP joints
oppose the pads of your thumb
more efficient grip
