muscles of the wrist Flashcards
primary roles of the muscles of the wrist
provide a stable base for the hand
adjust its position for optimal length-tension in the long finger muscles
work in synergy
flexor muscles
common origin from the medial epicondyle
all pass under the flexor retinaculum except the palmaris longus
prime wrist flexors
flexor carpi radialis
flexor carpi ulnaris
palmaris longus
flexor carpi radialis
will flex and radially deviate the wrist when working on its own
flexor carpi ulnaris
will flex and ulnarlly deviate the wrist
passes over the pisiform bone
functions as an anatomic pulley –> gets deflected for the joint axis–> increases the movement arm and produces torque
palmaris longus
flexor, but will tense the palmar fascia
assist elbow flexion and pronation
absent in 10% of the population
secondary movers
muscles recruited in time of need to move a larger load
flexor digitorum superficialis (FDS)
flexor digitorum profundus (FDP)
flexor pollicis longus (FPL)
primary responsibility is finger flexion
what are the secondary movers dependent on
as multi-joint muscles, their ability to produce force at the wrist is dependent on a synergetic stabilizer to prevent full excursion at more distal joints
need to be stabilized in extension to protect against becoming actively insufficient
extensor muscles
common origin from lateral epicondyle
primary wrist extensors
extensor carpi ulnaris
extensor carpi radialis brevis
extensor carpi radialis longus
extensor carpi ulnaris
will extend and ulnarlly deviate the wrist
acts as a stabilizer –> especially when were in wrist flexion –> important b/c wrist flexion tends to be an unstable position
extensor carpi radialis brevis
has a central location on the wrist d/t insertion on third metacarpal
pure wrist extensor d/t location
extensor carpi radialis longus
will extend and radially deviate the wrist –> d/t location of insertion on the second metacarpal
shows increased activity when either radial deviation or support against ulnar deviation is required
also active when forceful finger flexion motions are performed
BEST STABALZIER OF THE WRIST –> neutralizing synergy
secondary wrist extensors
extensor digitorum
extensor indicis
extensor digiti minimi
extensor pollicis longus
extensor pollicis brevis
abductor pollicis longus
all have the potential to produce wrist extenstion
where do EDM and EI insert
into the tendons of ED –> share a common function
ED will be more active
can also function as a wrist extensor
extrinsic musculature of the thumb
cross wrist and has potential to add to movement
but shows little activity
radial deviation
primarily a conjoint synergy b/w flexor carpi radialis and extensor carpi radialis longus
assisted by abductor pollicis longus and extensor pollicis brevis
ulnar deviation
primarily a conjoint synergy of flexor capri ulnaris and extensor carpi ulnaris
synergies at the wrist
conjoint synergy
neutralizing synergy
conjoint synergy
motions of flexion, extension, RD and UD
neutralizing synergy
during finger movements (flexion or extension)
you need activity of wrist musculature to prevent unwanted wrist movements
avoid active insufficiency
ex: finger flexion by FDS and FDP would result in wrist flexion unless there is contraction of wrist extensors
functional position of the wrist and hand
grasp is the most important position of the hand
position from which optimal function is most likely to occur
not necessarily the position of immobilization as this is depending on the disability
function position of the wrist and hand ( wrist measurements)
20 degrees of extension
10 degrees of ulnar deviation
putting the finger flexors at optimal length
functional position of the hand and wrist (finger measurements)
45 degrees of MP flexion
30 degrees of PIP flexion
slight flexion of DIP joints
wrist extensors are _____ joint muscles
two or three
susceptible to becoming actively and passively insufficient
extensors are actively insufficient when (too long)
too long –> can’t extend the wrist
elbow extension
wrist flexion
finger flexion
extensors are actively insufficient when (too short)
can’t flex the wrist
wrist extension
elbow flexion
finger extension
extensors are passively insufficient
elbow extension
wrist flexion
finger flexion
can ulnar/radial deviate to stretch a specific side
