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391 Cards in this Set

  • Front
  • Back
this joint is also known as a zone of architectural transition between the two bones of the forearm and the 5 metacarpals
wrist
what type of joint is the wrist?
ellipsoidal/biaxial
what are the two components of the wrist joint?
(1) radiocarpal
(2) midcarpal
this carpal bone is in the shape of a peanut
scaphoid
what carpal bone bridges across the midcarpal joint, making it more susceptible to injury?
scaphoid
what carpal bone is the most commonly fractured and is most slow to heal?
scaphoid
the surface of the scaphoid bone is mostly covered with __ cartilage
hyaline
this carpal bone is the keystone of the bones in the proximal row
lunate
is the volar or dorsal pole of the lunate thicker?
volar
in what direction does the lunate tend to dislocate?
volarly
this disease is avascular necrosis of the lunate
Keinbock's
during ulnar deviation, what carpal bone glides distally on the hamate?
triquetrum
what are the four carpal bones of the proximal row?
scaphoid, lunate, triquetrum, pisiform
what carpal bone is the only one with an insertion from a forearm muscle?
pisiform
what forearm muscle inserts on the pisiform?
flexor carpi ulnaris
what other carpal bone does the pisiform function with?
triquetrum
which way does the pisiform move during radial deviation and extension?
distally
which way does the pisiform move during ulnar deviation and flexion (due to the pull of the FCU?)
proximally
this carpal bone has a hook on the palmar side that forms the medial wall of the carpal tunnel
hamate
what carpal bone forms the medial wall of the carpal tunnel?
hamate
what carpal bone forms the lateral wall of Guyon's canal?
hamate
this structure is located between the neurovascular bundle and the flexor tendons in the carpal tunnel
hook of the hamate
what structure attaches at the hook of the hamate, that forms the roof of the carpal tunnel?
flexor retinaculum
the axis of rotation for RD, UD, flexion and extension goes through what carpal bone?
capitate
the capitate is firmly attached to the base of what metacarpal?
3rd
this carpal bone articulates with the scaphoid, capitate, trapezium, and the second metacarpal
trapezoid
what are the four carpal bones of the distal row?
trapezium, trapezoid, capitate, hamate
this carpal bone is the most important link between the carpals and the mobile thumb metacarpal
trapezium
what type of joint does the trapezium form when it articulates with the 1st MC?
saddle
the tubercle of what carpal bone makes up the lateral wall of the carpal tunnel?
trapezium
how much hand function would you lose if you lost the function of your thumb?
40-60%
what carpal bone is contained in the lateral column of the hand?
scaphoid
what carpal bones are contained in the central column of the hand?
lunate and entire distal row (trapezium, trapezoid, capitate, hamate)
what carpal bone is contained in the medial column of the hand?
triquetrum
what column of the hand is mobile and allows thumb movement?
lateral
what column of the hand corresponds to the axis of the hand?
central
what column of the hand allows rotation of the 5th metacarpal?
medial
when palmar concavity deepens, the carpal tunnel deepens due to movement at what joints?
intercarpal
what are the components of the carpal tunnel?
(1) all FDS tendons
(2) all FDP tendons
(3) flexor pollicis longus tendon
(4) median nerve
the concavity of the carpal tunnel plays an important role in balancing the forces of the long finger __ across the wrist with the wrist __
flexors, extensors
the surface of the radius has articulations for what two carpal bones?
scaphoid and lunate
does the triquetrum articulate with the distal ulna?
NO! articulates with the articular disc
how many degrees of palmar tilt is the articular surface of the radius in at the wrist?
12º
how many degrees of medial angulation is the articular surface of the radius in at the wrist?
15º
the palmar tilt of the radius at the wrist allows more movement into what motion?
more flexion than extension
does the radius or the ulna extend further at the wrist joint?
radius
when the scaphoid, lunate, and triquetrum extend on the distal end of radius and articular disc, in what directions are the roll and glide?
posterior roll, anterior glide
what shape are the articulating surfaces of the scaphoid, lunate, and triquetrum at the wrist?
convex
what shape are the distal end of the radius and articular disc of the ulna at the wrist?
concave
what type of joint is the medial side of the midcarpal joint?
compound saddle joint
what type of joint is the lateral side of the midcarpal joint?
plane
at the medial side of the midcarpal joint, what shape are the capitate and hamate?
convex
at the medial side of the midcarpal joint, what shape are the scaphoid, lunate, and triquetrum?
concave
at the lateral side of the midcarpal joint, what shape are the trapezium and trapezoid?
concave
at the lateral side of the midcarpal joint, what shape is the scaphoid?
convex
what are the thicker and stronger ligaments of the wrist, dorsal or volar?
volar
the dorsal ligaments of the wrist are reinforced by what structures?
extensor retinacular tunnels
what are the four extrinsic ligaments of the wrist?
(1) dorsal radiocarpal
(2) palmar radiocarpal
(3) TFCC
(4) radial collateral ligament
in what position is the palmar radiocarpal ligament taut?
full wrist extension
what are the three types of intrinsic ligaments of the wrist?
(1) short
(2) intermediate
(3) long
what are the most commonly injured intrinsic ligaments of the wrist?
intermediate
what are the three intermediate intrinsic ligaments of the wrist?
(1) lunotriquetral
(2) scapholunate
(3) scaphotrapezial
this long intrinsic ligament of the wrist is an inverted V, and controls the scaphoid
palmar intercarpal
this intrinsic ligament of the wrist helps to coordinate movements between the scaphoid and lunate
scapholunate
this extrinsic ligament of the wrist (which is part of the palmar radiocarpal ligament) guides scaphoid kinematics; it goes across the waist of the scaphoid so it dorsiflexes and volarflexes around this ligament
radioscaphocapitate
when the wrist extends, does the dorsal pole of the scaphoid go anterior or posterior?
posterior/dorsally
when the wrist flexes, does the dorsal pole of the scaphoid go anterior or posterior?
anterior/volarly
this ligament, which is part of the palmar radiocarpal ligament, acts as a volar sling for the lunate, preventing it from dislocating anteriorly
radiolunate
what three muscles act as important collateral support at the wrist?
(1) ECU
(2) EPB
(3) APL
what are the three functions of the TFCC?
(1) major stabilizer of distal radioulnar joint
(2) stabilizer of ulnar capsule
(3) cushion for load bearing between ulnar carpals and distal ulna
what are the five ligaments that provide support/stabilization to the scaphoid?
(1) radioscaphocapitate
(2) radioscapholunate
(3) scapholunate
(4) radial collateral
(5) V ligaments
what ligament limits the extremes of volarflexion of the scaphoid?
radioscapholunate
what bones do the V ligaments run between?
scaphoid to capitate and triquetrum to capitate
what is the close packed position of the wrist?
full extension
what is functionally the most important motion at the wrist?
extension
what is the normal range of wrist extension motion?
60-75º
during wrist extension, which way does the scaphoid move (which locks the joint)?
dorsiflexes
what is the normal range of wrist flexion motion?
70-85º
during wrist flexion, which way does the scaphoid move (which unlocks the joint)?
volarflexes
what are three structures that limit wrist extension?
(1) thick palmar ligaments
(2) anterior tilt of articular surface of distal radius
(3) muscles that flex wrist and fingers
what is the normal range of motion of radial deviation/abduction at the wrist?
15-20º
At what joint does radial deviation movement occur primarily?
midcarpal
during radial deviation, which way do the scaphoid and lunate move (causing the midcarpal joint to be unlocked)?
volarflexed
during radial deviation, which way does the distal row of carpals slide?
radially
during radial deviation, which way does the proximal row of carpals slide?
ulnarly
what is the normal range of motion of ulnar deviation/adduction at the wrist?
35-40º
in what forearm position is there greater ROM into ulnar deviation?
supinated
during ulnar deviation, which way does the scaphoid move (causing the midcarpal joint to be locked)?
dorsiflexed
what two movements does the triquetrum do during ulnar deviation?
(1) telescopes distally on hamate
(2) dorsiflexes
during ulnar deviation, which way does the proximal row of carpals slide?
radially
during ulnar deviation, which way does the distal row of carpals slide?
ulnarly
what is the minimum range of wrist flexion required for most ADLs?
40º
what is the minimum range of wrist extension required for most ADLs?
40º
what is the minimum range of wrist RD required for most ADLs?
10º
what is the minimum range of wrist UD required for most ADLs?
30º
this instability at the wrist occurs when the lunate stays relatively dorsiflexed due to injury of the scapholunate ligament; allows less flexion ROM
DISI (dorsal intercalated segmental instability)
this instability at the wrist occurs when the lunate remains in a relatively volarflexed position due to injury of the lunotriquetral ligament
VISI (volar intercalated segmental instability)
in DISI, is the lunate concavity facing dorsally or volarly?
dorsally
in VISI, is the lunate concavity facing dorsally or volarly?
volarly
what is the normal loading pattern for the wrist?
82% born by radius
18% born by ulna
this results from a lengthened ulna
positive ulnar variance
this results from a shortened ulna
negative ulnar variance
what are two things that can increase positive ulnar variance (make ulna longer)?
(1) forearm pronation
(2) strong grip
during static activities, what are the two positions of the wrist?
(1) 20-30º extension
(2) slight UD
this muscle at the wrist flexes and radially deviates, and also assists with elbow flexion and forearm pronation
flexor carpi radialis
what muscle of the wrist contracts during RD to counterbalance the extensor component of the ECRL?
FCR
what type of muscle is the FCR?
fusiform
what nerve innervates the FCR?
median
a weakness of what muscle may cause a decrease in forearm pronation and wrist flexor strength?
FCR
this muscle of the wrist flexes and UD the wrist, and assits in elbow flexion
flexor carpi ulnaris
this muscle powers activities such as axing, power stroke, karate chop, dart throwing
FCU
what nerve innervates the FCU?
ulnar
this muscle is a pure wrist flexor that tenses the palmar fascia and assists in elbow flexion
palmaris longus
during active finger extension, what muscles stabilize to prevent excessive wrist extension?
wrist flexors
what are five muscles that assist in wrist flexion?
(1) FDS
(2) FDP
(3) FPL
(4) APL
(5) EPB
overall, the extensors of the wrist have __% of the strength of the flexors
50%
this muscle extends and radially deviates the wrist; it is the main RD
ECRL
what muscle is most active as a synergist for fist making or prehension?
ECRL
what muscle is named as a wrist extensor, but has a larger moment arm for elbow flexion and RD of the wrist?
ECRL
the ECRL is most effective as a wrist extensor with the elbow in what position?
extended
this extrinsic muscle of the wrist solely extends the wrist
ECRB
this muscle extends and UD the wrist
ECU
the ECU is a better wrist extensor with the forearm in what position?
supination
what muscle is a stabilizer of the wrist during thumb abduction?
ECU
this muscle works synchronously with the ECRL and ED during wrist extension
ECU
what mucsle's tendon helps stabilize the head of the ulna?
ECU
what nerve innervates the ECU, ECRL, and ECRB?
radial
what are four muscles that assist wrist extension?
(1) ED
(2) EDM
(3) EI
(4) EPL
the ED assists wrist extension if the fist is in what position?
clenched
injury to this nerve results in wrist flexion during active finger flexion
radial
efficiency of the finger flexors with the wrist flexed is only __% of that with the wrist extended
25%
what are the seven radial deviators of the wrist?
(1) ECRL
(2) ECRB
(3) FCR
(4) APL
(5) EPL
(6) EPB
(7) FPL
what are the two primary ulnar deviators of the wrist?
(1) FCU
(2) ECU
what are three muscles that assist in ulnar deviation of the wrist?
(1) FDP
(2) FDS
(3) ED
what type of joint is the CMC joint of the thumb?
saddle
how many degrees of freedom are there at the CMC Joint of the thumb?
2
during adduction at the CMC joint of the thumb, what are the directions of roll and slide?
posterior roll, anterior glide
during abduction at the CMC joint of the thumb, what are the directions of roll and slide?
anterior roll, posterior glide
during flexion at the CMC joint of the thumb, what are the directions of the roll and slide?
ulnar roll and ulnar glide
during extension at the CMC joint of the thumb, what are the directions of the roll and slide?
posterior roll, posterior glide
the MC is what shape for thumb CMC ab/adduction?
convex
the MC is what shape for thumb CMC flexion/extension?
concave
in the capsular pattern of the CMC of the thumb, what motion is most limited, and followed by what other motion?
abduction most limited, followed by extension
what is the closepacked position of the thumb CMC joint?
full opposition
what is the resting position of the thumb CMC joint?
midway between flex/ext and ab/add
what are the five ligaments that reinforce the capsule of the CMC joint of the thumb?
(1) strong UCL
(2) anterior oblique
(3) posterior oblique
(4) RCL
(5) 1st intermetacarpal
what three movements cause the anterior oblique ligament of the CMC joint of the thumb to be taut?
(1) abduction
(2) extension
(3) opposition
what three movements cause the ulnar collateral ligament of the CMC joint of the thumb to be taut?
(1) abduction
(2) extension
(3) opposition
what two movements cause the 1st intermetacarpal ligament of the CMC joint of the thumb to become taut?
(1) abduction
(2) opposition
what two movements cause the posterior oblique ligament of the CMC joint of the thumb to be taut?
(1) abduction
(2) opposition
what movements cause the radial collateral ligament of the CMC joint of the thumb to be taut?
all movements to varying degrees, except extension
when the thumb is used in these two positions, the ligaments of the CMC joint of the thumb need the assistance of the balanced forces from the muscles to maintain optimal joint alignment
adduction and flexion
what range of thumb CMC flexion is available?
45-50º
what range of thumb CMC extension is available?
10-15º
what range of thumb CMC abduction is available?
45º (from the palm)
what range of thumb CMC adduction is available?
to palm of hand
thumb CMC opposition is a combination of what three movements?
(1) abduction
(2) medial rotation
(3) flexion
what type of joints are the 2nd and 3rd CMC joints?
plane
what are the articulating bones that form the 2nd and 3rd CMC joints?
trapezium, trapezoid and capitate articulate with the base of the 2nd and 3rd metacarpals
what is usually the only motion allowed at the 2nd and 3rd CMC joints?
gliding
what type of joint is the 4th CMC Joint?
plane
what type of joint is the 5th CMC joint?
saddle/pseudosaddle
what are the articulating bones that form the 4th and 5th CMC joints?
hamate and capitate articulate with the bases of the 4th and 5th MCs
how much flexion/extension ROM is allowed at the 4th CMC?
20º
how much flexion/extension ROM is allowed at the 5th CMC?
28º
what type of joint are the intermetacarpal joints?
irregular or plane
what are the articulating surfaces of the intermetacarpal joints?
between 2nd-5th MC bases
what movement is allowed at the intermetacarpal joints?
sliding (helps with hand cupping)
what side of the hand does more sliding occur at the intermetacarpal joints?
ulnar
what type of joint are the 2nd-5th MP joints?
condyloid, biaxial
at the MP joints of the 2-5th fingers, what shape is the MC head?
convex
at the MP joints of the 2-5th fingers, what shape is the proximal phalanx surface?
concave
where is the axis of motion of the 2-5th MP joints?
through the head of the MCq
this is a thick, dense fibrocartilaginous plate on the palmar surface of the joint between the collateral ligaments
volar plate
what movement does the volar plate prevent?
hyperextension
the thickness of the volar plate increases the moment arm for what tendons by increasing the distane between the tendon and the joint axis?
finger flexor tendons
these are strong rounded cords along the sides of the joints of the fingers
collateral ligaments
what positions are the upper collateral ligaments of the 2-5th fingers taut and slack in?
slack in extension (allowing finger ab/add) and taut in flexion (stability for grip)
what positions are the accessory collateral ligaments of the 2-5th fingers taut and slack in?
taut in extension, and slack in flexion
these ligaments are wide bands that connect the volar plates of the 2-5th MP joints, and they limit abduction of the metacarpals
deep transverse metacarpal ligament
what positions are the deep transverse metacarpal ligaments taut and slack in?
slack in adduction, taut in abduction
what muscles are located anterior to the deep transverse MC ligament?
lumbricales
what muscles are located posterior to the deep transverse MC ligament?
interossei
what ligament of the hand helps to preserve the MC arch?
deep transverse metacarpal ligament
the capsule at what joint of the finger is the loosest?
MP
what is the close packed position of the hand?
MP flexed, IPs extended
what range of flexion is allowed at the 2-5th MP joints?
90º (increases at pinky)
what range of extension is allowed at the 2-5th MP joints?
+10-20º actively
what range of radial deviation is allowed at the 2-5th MP joints?
9-19º
what range of ulnar deviation is allowed at the 2-5th MP joints?
20-43º
what are the directions of the roll and glide at the 2-5th MP joints during flexion?
anterior roll, anterior glide
what are the directions of the roll and glide at the 2-5th MP joints during extension?
posterior roll, posterior glide
what carpal bones do the fingers orient toward when flexed (with NORMAL MP joint motion)?
scaphoid
is there a tighter grip on the radial or ulnar side of the hand?
ulnar
what type of joint is the MP of the thumb?
condyloid
how many degrees of freedom are there at the MP joint of the thumb?
2
what is the closepacked position of the thumb MP joint?
flexion
what ligament is more easily stretched/injured at the thumb MP joint, RCL or UCL?
UCL
this injury is a stretch of the thumb UCL
Gamekeeper's thumb
what two tendons on the palmar side of the MP joint of the thumb contain sesamoid bones?
(1) flexor pollicis brevis
(2) adductor pollicis
what range of flexion is allowed at the thumb MP joint?
45-90º
what range of extension is allowed at the thumb MP joint?
what type of joints are the IP joints at the fingers?
hinge/uniaxial
what is the shape of the proximal segment at the IP joints of the fingers?
convex
what is the shape of the distal segment at the IP joints of the fingers?
concave
at the IP joints, when are the collateral ligaments taut?
remain taut throughout range because of broad transverse dimension of head of proximal phalanx
what positions are the accessory collateral ligaments of the IP joints of the fingers taut and slack in?
slack in flexion, taut in extension (like volar plate)
at the MP joints of the 2-5th fingers, which collateral ligaments are longer, contributing to increased ulnar deviation?
radial collateral
what range of flexion is allowed at the PIP joint of the fingers?
100-120º
what range of flexion is allowed at the DIP joint of the fingers?
70-90º
what range of extension is allowed at the IP joints of the fingers?
0º actively (DIP can get more passively)
what is the range of flexion allowed at the thumb IP joint?
70º
what is the range of extension allowed at the thumb IP joint (passively)?
20º (increases throughout life)
what is the most stable arch of the hand (located at the level of the carpal tunnel)?
tranverse carpal arch
what is the keystone of the transverse carpal arch of the hand?
capitate
this arch of the hand is formed by the MCs and phalanges; stability of the MP joints and volar plates are essential to preserve this arch
longitudinal arch
what are the five extrinsic muscles of the fingers?
(1) ED
(2) EI
(3) EDM
(4) FDP
(5) FDS
this muscle extends the MP joints of the fingers via attachment into sagittal bands, and assists with IP extension of MPs are not fully extended; assists in abduction of fingers and with wrist extension and RD
extensor digitorum
if the ED muscle is unopposed, what would occur at the fingers?
MP joints hyperextended (claw)
what is the only muscle that extends the MP joints of the fingers?
ED
what muscle is active during making a fist to slow down MP flexion so the FDP and FDS can flex the IP joints before using up their excursion?
ED
what two positions of the hand would indicate shortness of the ED?
(1) hyperextension of MPs if wrist flexed
(2) extension of wrist if MPs flexed
this muscle extends the index finger MP joint and assists with IP extension and adduction of the index finger
EI
this muscle extends the 5th MP joint, assists in IP extension and abduction of the 5th finger
EDM
this muscle flexes the DIP of fingers, assists in flexion of PIP, MP, CMC, and wrist; assists in adduction
FDP
this arch of the hand is formed by the MCs and phalanges; stability of the MP joints and volar plates are essential to preserve this arch
longitudinal arch
what are the five extrinsic muscles of the fingers?
(1) ED
(2) EI
(3) EDM
(4) FDP
(5) FDS
this muscle extends the MP joints of the fingers via attachment into sagittal bands, and assists with IP extension of MPs are not fully extended; assists in abduction of fingers and with wrist extension and RD
extensor digitorum
if the ED muscle is unopposed, what would occur at the fingers?
MP joints hyperextended (claw)
what is the only muscle that extends the MP joints of the fingers?
ED
what muscle is active during making a fist to slow down MP flexion so the FDP and FDS can flex the IP joints before using up their excursion?
ED
what two positions of the hand would indicate shortness of the ED?
(1) hyperextension of MPs if wrist flexed
(2) extension of wrist if MPs flexed
this muscle extends the index finger MP joint and assists with IP extension and adduction of the index finger
EI
this muscle extends the 5th MP joint, assists in IP extension and abduction of the 5th finger
EDM
this muscle flexes the DIP of fingers, assists in flexion of PIP, MP, CMC, and wrist; assists in adduction
FDP
which muscle has a larger moment arm at the PIP, FDP or FDS?
FDP
which muscle has a larger moment arm at the wrist and MP, FDP or FDS?
FDS
which finger flexor is more active during light finger flexion?
FDP
which finger flexor contributes more to finger flexion when there is a load placed?
FDS
what is the only muscle that flexes the DIP joints of the fingers?
FDP
what two positions will the hand be in if there is shortness of the FDP?
(1) flexion of fingers if wrist extended
(2) flexion of wrist if fingers extended
which finger flexor muscle needs stabilization of all other fingers during the MMT?
FDS (becasue you prevent FDP from working on tested finger because FDP is connected)
this muscle flexes the PIP of fingers, assists in MP, CMC, and wrist flexion
FDS
this muscle functions alone only when DIP flexion of the fingers is not required
FDS
this muscle powers the most individual finger motion
FDS
what would be the presentation of a contracture of the FDP muscle?
flexion deformity of DIP joints
what would be the presentation of a contracture of the FDS muscle?
flexion deformity of the PIP joints
what two positions would the hand be in if the FDS was short?
(1) flexion of PIP if wrist extended
(2) flexion of wrist if PIPs extended
for tendon gliding, during a straight fist, what muscle glides maximally with respect to the sheath and bone?
FDS
for tendon gliding, during a hook fist, there is maximum gliding between what structures?
the tendons of the FDS and FDP
for tendon gliding, during a regular fist, there is maximum gliding of what muscle with respect to the sheath and bone?
FDP
if there is no counterbalancing extensor force at the wrist, then when the finger flexors contract, what will they cause the wrist to do?
flex
what are the four extrinsic muscles of the thumb?
(1) APL
(2) EPB
(3) EPL
(4) FPL
this muscle abducts and extends the CMC joint of the thumb, and assists in RD and flexion at the wrist
abductor pollicis longus
what muscle maintains the arch of hte pinch by preventing collapse of the thumb MC under the influence of adductors?
APL
what would a contracture of the APL muscle present as?
abducted and slightly extended position of 1st MC with slight RD of wrist
what muscle is found in the 1st extensor compartment of the wrist?
APL
to test the length of the APL, what would you do?
flex thumb, UD wrist, and slightly extend wrist
this muscle extends the thumb MP joint, extends and abducts CMC of thumb, assists in RD and flexion of the wrist
EPB
weakness of what thumb muscle decreases the ability to extend the thumb MP joint and may result in a position of thumb MP flexion?
EPB
this muscle extends the IP joint of the thumb, assists in thumb MP and CMC extension, and assists in RD and extension of the wrist
EPL
at the thumb CMC joint, what muscle is an extensor and adductor
EPL
to test the integrity of this muscle, you would see if someone could lift their thumb off the table
EPL
if the thumb adducts as the person is extending it, what muscle is working too much and what is not working enough?
EPL too much, APL not enough
this muscle flexes the IP joint of the thumb and assists in flexion of the MP, CMC of the thumb and may assist in wrist flexion
FPL
if there is marked weakness of this muscle, you may develop a hyperextension deformity of the IP joint of the thumb
FPL
what is the only thumb IP joint flexor?
FPL
to test the length of the FPL, what would you do?
(1) extend thumb
(2) extend wrist
(3) slight UD
if short, IP joint will flex
this muscle abducts the 5th MP and assists in opposition of CMC and flexion of 5th MP; may assist in IP extension of 5th due to small insertion into extensor expansion
ADM
in normal hand cupping, the ADM contraction is accompanied by contraction of what other muscle in order to stabilize the pisiform bone?
FCU
this muscle flexes the MP of the 5th finger and may assist in opposition of CMC of 5th finger
FDM
this muscle flexes and rotates the CMC of the 5th finger
opponens digiti minimi
a weakness in this muscle causes flattening of the palm (makes it difficult to oppose little finger)
ODM
this muscle abducts index, middle, and ring finger, assists in flexion of MPs and extension of IPs
dorsal interossei
this muscle may assist in adduction of the thumb
1st dorsal interosseous
what intrinsic hand muscles are active in power grip?
dorsal interossei
what shape are the dorsal interossei muscles?
bipennate
which muscle has 4x as much force as the lumbricales?
dorsal interossei
are the dorsal interossei volar or dorsal to the axis of motion at the MP joints of the fingers?
volar
are the dorsal interossei volar or dorsal to the axis of motion at the IP joints of the fingers?
dorsal
the moment arm for flexion for the dorsal interossei increases as the MP does what motion?
flexes
the angle of pull of this muscle is such that it would stabilize the base of the 1st MC from dorsoradial subluxation
1st dorsal interosseous
these muscle adduct the thumb, index, ring, and small fingers; assists in MP flexion and IP extension, and are unipennate
palmar interossei
what shape are the palmar interossei muscles?
unipennate
what position would you put the hand in to test the length of the interossei muscles?
flex IPs, extend MPs
these muscles extend IPs and simultaneously flex MPs of finger, and extend the IPs with the MPS extended
lumbricales
these muscles are rich in sensory organs to balance flexor and extensor tension; and suppress flexor tension to correct clawing
lumbricales
what side of the finger are the lumbricales located on?
radial side
what muscles in the hand have a longer excursion and are farther fro the joint axis than the interossei, but don't produce as much force because the interossei have more fibers?
lumbricales
this muscle pulls the extensor mechanism proximally, which increases tension in the extensor hood
lumbricales
this muscle abducts the CMC and MP at the thumb, and assists in thumb IP extension
APB
what would weakness of the APB cause?
difficulty grasping large objects due ot difficult abducting thumb
this muscle flexes both the MP and CMC joints of the thumb, and assists in IP extension and opposition
FPB
what would a contracture of the FPB muscle present as?
flexion deformity of MP joint of thumb
this muscle opposes the MC joint of the thumb, rotates the thumb into pronation
opponens pollicis
what would a weakness of the opponens pollicis present as?
flattening of thenar emminence and difficulty holding a pencil for writing or grasping objects firmly between thumb and fingers
this muscle adducts the CMC joint of the thumb, adducts and assists flexion of MP of thumb, and assists thumb IP extension
adductor pollicis
what nerve innervates the adductor pollicis?
ulnar nerve
what muscle has the best torque potential of any other thumb CMC muscle?
adductor pollicis
most commonly during function, the thumb is in what two positions?
adduction and flexion
what are five forces that contribute to alteration in the mechanical forces at the CMC Joint of the thumb?
(1) adduction and flexion during function
(2) insufficient function of APL, APB, 1st DI to stabilize CMC
(3) shortness and overuse of MP flexors and adductor of thumb
(4) weak EPB
(5) ligament laxity
the MP extension at the fingers occurs via what structure in the extensor mechanism?
sagittal bands
PIP extension at the fingers occurs via what structure in the extensor mechanism?
central slip
DIP extension at the fingers occurs via what structure in the extensor mechanism?
terminal tendon
what are the five components of the extensor mechanism (muscles)?
(1) ED
(2) EI
(3) EDM
(4) lumbricales
(5) interossei
this part of the extensor mechanism attaches at the base of the middle phalanx
central slip
this part of the extensor mechanism attaches at the base of the distal phalanx
terminal tendon
normally, the lateral bands of the extensor mechanism are volar or dorsal to the PIP and DIP joints at the fingers?
dorsal
this deformity of the hand occurs when the central slip of the extensor mechanism is avulsed, causing DIP hyperextension and PIP flexion (because lateral bands slip volarly)
Boutonneire deformity
shortness of what ligament of the finger contributes to a Boutonneire deformity?
oblique retinacular ligament
this deformity is when the volar plate is too lax and the interossei are short, causing MP flexion, PIP hyperextension, and DIP flexion
swan neck deformity
this deformity occurs from rupture of the terminal tendon of the extensor mechanism, causing a loss of active DIP extension
mallet finger
in a mallet finger deformity, the extensor mechanism may retract, causing increasing tension on the central slip and creating a secondary deformity of what type?
swan neck (PIP hyperextension)
this deformity occurs when there is a loss of intrinsic muscle stabilization; the ED is no longer balanced by the intrinsics resulting in MP hyperextension and IP flexion (Because ED cannot extend IP joints)
clawing
a clawhand deformity can occur due to what nerve injury?
ulnar
during an ulnar nerve injury, which fingers claw the worst since they are solely innervated by the ulnar nerve?
4th and 5th
this apparatus prevents bowstringing of the flexor tendons
flexor apparatus
how many annular and cruciate pulleys are there in the flexor apparatus of the fingers?
4 annular, 3 cruciate
what are the two most important pulleys in the flexor apparatus of the fingers?
A2 and A4
this is when the flexor tendons relatively lengthen with respect to the skeleton, decreasing their efficiency and not allowing you to make a full fist
bowstringing
the flexor tendons of the fingers cross the MP joint at what type of angle?
ulnar angle
these finger flexor tendons insert on the distal phalanx
FDP
these finger flexor tendons insert by two slips at the base of the middle phalanx
FDS
how do you stretch the oblique retinacular ligament of hte finger?
simultaneously extend PIP and flex DIP
what is the normal sequence of finger flexion?
PIP then MP then DIP
what is the normal sequence of finger extension?
MP then DIP then PIP
if there is a short arc of motion for finger flexion, what muscle is not working?
interossei
Froment's sign is a quick test for injury to this nerve; a person grasps a piece of paper, and their IP joint flexes instead of staying in extension
ulnar
in Froment's sign, when the IP flexes, what muscle is working too much and what is working too little?
FPL too much, adductor pollicis too little
an injury to what nerve would cause loss of the FDP, causing inability to actively flex DIP and MP joints of small and ring fingers?
ulnar
an injury to what nerve would cause atrophy of the hypothenar muscles?
ulnar
an injury to what nerve would cause loss of power grip and a poor pinch grip?
ulnar
an injury to what nerve would cause atrophy of the thenar emminence?
median
an injury to this nerve would result in inability to flex DIP and PIP joints of index and middle fingers and weak PIP flexion of ring and small
median
an injury to what nerve would cause loss of abduction and opposition of the thumb?
median
an injury to what nerve owuld cause loss of the lumbricales, causing inability to completely actively extend IP joints of middle and index fingers?
median
an injury to what nerve would cause a loss in wrist flexion and pronation strength?
median
an injury to what nerve presents with wrist drop?
radial
what is a quick test for the integrity of the radial nerve?
ask someone to extend fingers; will only extend at IPs, not MCP
an injury to what nerve would cause a loss of wrist, finger, and thumb extensors?
radial
an injury to what nerve would cause active insufficiency of finger flexors due to loss of wrist extensors?
radial
an injury to what nerve would cause a flexion posture of the thumb?
radial
what muscle is active during the three jaw chuck pinch?
opponens pollicis
what muscle is active during the key pinch (and is the strongest pinch)?
adductor pollicis
what muscle is active during tip to tip pinch?
flexor pollicis longus
what force results at the elbow during resisted shoulder medial rotation?
valgus
if there is a positive ulnar variance at the wrist, are there higher or lower compressive forces at the joint?
higher
what kind of stress is placed at the volar plate of the PIP joint with a swan neck deformity?
tension
what thenar muscles are active during a gentle grasp (opposition of thumb with any of the other fingers)?
opponens pollicis predominates
APB>FPB
what thenar muscles are active with firm opposition of thumb to the index or middle finger?
FPB>Opponens
AdPollicis>AbPB
what thenar muscles are active with firm opposition of the thumb to the ring finger?
Opponens increases but still <FPB
AbPB increases but still <AdPollicis
what thenar muscles are active with firm opposition of the thumb to the small finger?
opponens=FPB
abductor pollicis brevis=adductor pollicis
this is the type of grip one has when holding a tennis racket
cylindrical grip
this is the type of grip one has when holding a baseball
spherical grip
this is the type of grip one has when holding a brief case handle
hook grip
this is the type of grip one has when holding a cigarette
lateral prehension
what are the four types of power grips?
(1) cylindrical
(2) spherical
(3) hook
(4) lateral prehension
this is the type of grip someone has when holding a quarter
pad to pad prehension
this is the type of grip someone has when holding a straight pin
tip to tip prehension
this is the type of grip someone has when pinching a key
pad to side prehension
what are the three types of precision handling grips?
(1) pad to pad prehension
(2) tip to tip prehension
(3) pad to side prehension
in the cylindrical grip, what finger flexor is active in the dynamic phase?
FDP
in the cylindrical grip, what finger flexor is active in the static phase?
FDS
in the cylindrical grip, what muscles are active and function as MP flexors, abductors, and adductors?
interossei
in the cylindrical grip, what finger intrinsics are relatively silent?
lumbricales
in the power grip, what muscle acts as a stabilizer to increase joint stability and compression?
ED
are the thenar muscles active during cylindrical grip?
yes (FPL and thenar muscles all active)
a distinguishing characteristic between power grip and precision handling is that what muscle is very active in power grip?
adductor pollicis
are the hypothenar muscles active in cylindrical grip?
yes
the main difference in this grip from the cylindrical grip is that the finger spread leads to increased interosseous activity
spherical grip
what is the major muscle activity during a hook grip?
FDP and FDS (some interosseous)
does a hook grip ever include the thumb?
NO, may include palm
during lateral prehension, what is the position of the MP and IP joints?
extension, MP simultaneously abducted or adducted
during lateral prehension, these muscles help extend the fingers
lumbricales, ED
during lateral prehension, these muscles help ab/adduct the fingers
interossei
what type of muscular activity occurs during precision handling?
isotonic
what type of fine grip accounts for about 80% of precision handling?
pad to pad prehension
what muscle is used if the DIP is flexed in a grip?
FDP
what muscle is used if the DIP is extended in a grip?
FDS
what muscles supplement MP flexion force and ab and adduction at the MP joints during a grip?
interossei
the activity of what muscle increases with the pressure of the pinch?
adductor pollicis
what muscle controls IP flexion of the thumb during a grip?
FPL
what is the most precise form of grasp?
tip to tip prehension
what is the difference between pad to pad and tip to tip prehension?
need full IP joint flexion, and MP must ulnarly deviate
what three muscles are used during tip to tip prehension?
FDP, FPL, interossei
what 7 muscles are used during pad to pad prehension?
(1) FDP if DIP flexed
(2) FDS if DIP extended
(3) interossei
(4) opponens pollicis
(5) FPB
(6) APB
(7) adductor pollicis
what is the least precise form of pinch?
pad to side prehension
what is the difference between pad to side prehension and other forms of prehension?
thumb more adducted and less rotated
during pad to side prehension, the activity of what muscles increases?
FPB, adductor pollicis
during pad to side prehension, the activity of what muscle decreases?
opponens
what type of grip can be performed using tenodesis with paralysis of the hand muscles by extending the wrist?
pad to side prehension