lecture 11: wrist and hand Flashcards
what carpal bones are in the proximal row
scaphoid. lunate, triquetrum, pisiform
what carpal bone sits on the triquetrum
pisiform
what carpal bones are in the distal row
trapezium, trapezoid, capitate, hamate
true or false: the capitate bone is part of the proximal roq
false, the distal row
what carpal bone sits at the base of the thumb
the trapezium
which carpal bone is the keystone/main anchor of the carpus
capitate
be able to name the carpal bones and if they are in the distal or proximal row
why is there such a tight fit of the carpal bones
to allow for stability
what are the smoothest lines of the wrist called
gilula lines
what percentage of force transmission occurs at the distal radius in the normal wrist
80%
true or false: the scaphoid has 2 regions
false, 3 regions
what are the 3 regions of the scaphoid
distal pole
proximal pole
wasit
what is another name for the scaphoid bone in the wrist
navicular
what region of the scaphoid is poorly vascularized
proximal pole
since the proximal pole of the scaphoid is poorly vascularized, what is it susceptible to
avascular necrosis
how is the scaphoid frequently fractured
by fall on hyperextended radially deviated wrist
true or false: the scaphois is frequently fractured by fall on hyperextended ulnar deviated wrist
false, radially
where can you palpate the scaphoid
snuff box
what bone is considered an important stabilizer of the carpus (not the scaphoid)
lunate
what carpus bone has very little movement
luante
true or false: the lunate has very limited movement
true
true or false: the scaphoid bone is the only bone vulnerable to avascular necrosis
false , the lunate as well
what is keinbocks disease
condition where the blood supply to one of the small bones in the wrist, the lunate, is interrupted.
true or false: the lunate is also vulnerable to avascular necrosis
true (keinbocks disease)
what are the regions of the hamate
proximal pole and hook and body
what carpus bone is the site of attachment of the flexor retinaculum
hammate
true or false: the capitate is the site of attachment of the flexor retinaculum
false, the hamate is
where can you palpate the hamate
near base of pinky
what is the bone that is saddle shaped at the base of the thumb
trapezium
what two carpus bones contribute to the anterior orientation of the thumb
trapezium and scaphoid
the trapezium and the scaphoid together contribute to what and why is that important
to the anterior orientation of the thumb
(important for grasp)
what is the larges carpal bone
capitate
where is the capitate located
orientated at the base of the long finger
what bone is the stable base for the index finger
trapezoid
what bone is located at the base of the index finger important for pimch
trapezoid
true or false: the capitate bone is important for pinch
false, the trapezoid
what carpal bone articulates with the fibrocartiligenous disc and pisiform
triquetrum
true or false; the pisiform is a sesamoid bone
true
what are the 3 main joints of the wrist
distal radioulnar joint (DRUJ)
radoiocarpal joint
mid-carpal joint
what is the force transmission at the radius-carpus during radial deviation
87%
what is the force transmission at the ulna-carpus during rotatio
37%
what is the force transmission at the mid carpal (neutral) of the scaphotrapezium-trapezoid
31%
what are the bony parts of the radoiocarpal joint
radius and the proximal carpal row
in the radoiocarpal joint, the radius articulates with what carpal boens
scaphoid and lunate
what motions does the radoiocarpal joint contribute to
flexion, extension and radial-ulnar deviation
what is the primary function of the distal radioulnar joint
forearm pronation and supination
what does the distal radioulnar joinnt facilitate
load transmission between radius-hand and ulna
true or false: the radio carpal joint facilitates load transmission between radius-hand and ulna
false, the distal radioulnar joint does
extrinsic ligaments of the wrist are orientaed towards where
midline
what does it mean for a wrist ligament to be extrinsic
from radius/ulna to carpal bones
(oriented towards the midline)
are the intrinsic or extrinsic ligs v shaped
extrinsic
are the volar ligaments or dorsal ligaments of the extrinsic ligaments on the wrist stronger
volar ligaments are stronger
what is the function of the extrinsic wrist ligaments
stabilize the carpus during extension (force transmission during weight bearing)
what are the static stabilizers of the DRUJ
TFCC
ECU (including sheath)
interosseous membrane
what are the dynamic stabilizers of the DRUJ
pronator quadratus
pronator teres
biceps brachii (inserion tuberosity of the radius and deep fascia of FA)
supinator (intertion lateral, proximal shft of radius)
what are the 4 things that make up the TFCC
dorsal radioulnar ligament (DRUL)
palmar radioulnar ligament (PRUL)
ECU
articular disk
what does the article disk of the TFCC function
increases the surface area of distal ulna and shock absorption
what are the 4 functions of the TFCC
stabilization of the DRUJ and ulnar side of carpus
cushion ulna on carpus
allows axial loading of ulna on forearm
increases articular surface of carpus
true or false: The TFCC stabilizes the DRUJ and radial side of the carpus
false, ulnar
where is the mid carpal joint formed
between two carpal rows (b/w distal and proximal)
what does the mid carpal joint contribute to
flexion
extension
radial-ulnar deviation
how is the mid carpal joint stabilzied
stabilization via ligaments and capsule
accord to garcia ellas, 2013, which joint is more important: the mid carpal or radoiocarpal joint
midcarap
true or false: the proximal row has no tendinous inserions
true
where does wrist mvovment start
distal row of carpus
explain wrist movement and how mid carpal is more important that radoiocarpal joint
proximal row has no tendinous insertions
wrist movement starts at distal row of carpis
movement pulls mid carpal ligaments taut, creates a compressive load and moves proximal row
what is the orientation of the intrinsic ligaments of the wrist
transverse orientation
what does it mean to be an intrinsic ligament of the wrist
carpal to carpal
what are the two important intrinsic ligaments
scapholunate (interesses) ligament
lunotriquetral interosseous ligament
in an xray, if there is space between the scaphoid and lunate, what ligament is ruptured
scapholunate
what is the most common wrist ligament injury
SL ligament (scapholunate)
true or false: The SL lig rupture is most common wrist ligament injury
true
what is a common cause of carpal instability and the most common wrist lig injury
SL ligament rupture
true or false: there is higher SL lig tensile force in flexion
false, extension
in what position is there higher SL ligament tensile force
extension
what is the common name of an Scapholunate ligament tear
terry thomas sign (space between scaphoid and lunate)
what are the two types of intrinsic ligament dissociation
volar
(volar intercalary segment instability(
dorsal
(dorsal intercalary segment instability)
explain volar intercalary segment instability
L-T ligament rupture (plus dorsal radoiocarpal and volar radiocarpal)
=lunate points in a volar direction
explain dorsal intercalary segment instability
SL ligament rupture (plus scaphotrapeziumtrapezoid or dorsal inter carpal)
-lunate points in a dorsal direction
VISI is associated with LT or SL ligament rupture
LT
DISI is associated with LT or SL ligament rupture
SL ligament
in the study of incidence of carpal instability two years after fall on outstretched hand, what percentage had clinical evidence of carpal instability
44%
in the study of incidence of carpal instability two years after fall on outstretched hand, 44% had clinical evidence of carpal instability, of those 44% how many had scapho-lunate dissocaiteion
24%
what happens if you get an untreated scapholunate ligament injury
scapholunate advanced collapse (SLAC wrist)
=capitate will descend and fill in the empty spot
are ligaments the only wrist stabilizers
no , we are able to surpass the tensile strength of wrist ligaments without rupture
true or false: scapholunate ligament is more than just a passive restraint
true
explain how the scapholunate ligament is more than just a passive restraint
there are mechanoreceptors in ligaments that signal joint perturbation and influence surrounding muscles
=reactions are protection
the centre of rotation in the wrist goes through what bone
capitate
with a distal radius fracture, which movement would be more problematic
extension because it has a greater contribution of radiocapral
during flexion, explain the joint contribution of the radoiocarpal and mid carpal
40% radiocapral
60% mid carpal
during extension, explain the joint contribution of the radoiocarpal and mid carpal
33.5% mid carpal
66.5% radoiocarpal
there is a higher contribution from radoiocarpal or midcarpal during extension
radoiocarpal
explain the movement of the carpals during flexion
distal and proximal carpal rows both move into flexion
explain the movement of the carpals during extension
distal and proximal carpal rows both move into extension
explain the symbolic movement of wrist flexion and extension
carpal rows act like 2 cylinders rolling in the same direction
explain the carpal kinematics during radial deviation
1) proximal row flexes and translates ulnarly
2) lunate pronates
3) triquetrum rides proximally and dorsally on hamate
explain the carpal kinematics during ulnar deviateion
1) proximal row extends and translates radially
2) lunate supinates
3) triquetrum rides distally and volarly on hamate
a terry thomas sign is a radiographic indicator of what
scapholunate ligament rupture
there is greater mobility with what finger bones
with ring and little finger metacarpals
why is there different metacarpal lengths
cascade/convergence
=natural cascade towards base of thumb
what are the 3 arches of the hand
fixed transverse proximal arch
movile distal transverse arch
longitudinal arch
where is the fixed transverse proximal arch
mid point = capitate
the proximal transverse arch is fixed or movile
fixed
the distal transverse arch is fixed or mobile
mobile
what is the midpoint of the mobile distal transverse arch
3rd metacarpal
which is mobile: the distal or proximal transverse arch
distal
along what metacarpal does the longitudinal arch of the hand lie
3rd metacarpal
since the metacarpals are different lengths what does that mean
there is a volar arch
what type of joint is the MCP (in fingers)
condylyar
what are the movements possible for MCP
flexion/extension
abduction/adduction
what type of joint are the PIP and DIP joints
hinge
what are the movements possible at the PIP and DIP joints
flexion and extension
true or false; the finger joints are synovial
true
what are the finger ligaments
ulnar and radial collateral ligaments (cord and accessory(
volar (palmar plate)
in which position are the collateral ligaments of the finger most taut
PIP and DIP closed pack position is in full extension
collaterals at MCP are tight when flexion
what is the MCP ROM (in fingers) during flexion extension
flexion: 90
extension 0
what is the PIP ROM during flexion extension
flexion: 100
extension: 0
what is the DIP ROM during flexion
flexion: 80
extension 00
true or false: the MCP gets 100 degrees of flexion
false, the MCP gets 90
the PIP gets 100
which joint has most flexion ROM: the MCP< PIP or DIP
PIP
according to evans, whas is the minimal DIP flexion needed
70
thumb makes up what percentage of hand function
60%
what type of joint is the MCP joint at the thumb
biaxial joint
what are the motions possible at the MCP joint of the thumb
flexion/extension
abduction/adduction
what type of joint is the IP joint at the thumb
hinge joint
what are the movements possible at the IP joint of the thumb
flexion/exnesion
what type of joint is the CMC of the thumb
saddle joint
what movements are possible at the CMC joint of the thumb
flexion/extension
abduction/adduction
circumfuction and opposition
what is the normal ROM in the MCP joint of the thumb
flexion: 55 degrees
hyperextension: 10 degrees
what is the normal ROM of the IP joint of the thumb
flexion: 80
extension: 0
what is the normal ROM of palmar abduction of the thumb
45 degrees
what are the dynamic stabilizers of the CMC joint of the thumb
ADD
APD
OPP
FPB
APL
FPL
EPB
EPL
what are the static stabilizers of the CMC
16 ligaments
most important arte palmar oblique (beak) ligament and dorsoradial ligament
with more lateral pinch force, what happens do the CMC joint contract force
it increases
what can happens with erosive chagnes with osteoarthritic
CMC subluxation
what is shoulder sign indicative of
dorsal radial dislocation of 1st MC (CMC)
tilting in dorsal radial direction
what are the extrinsic musculotendinous structure flexors
flexor digi superficualis (FDS)
flexor digi profundus (FDP)
flexor pol longus (FPL)
palmaris longus (PL)
what position would allow for optimal differential glide of FDS and FDP
hook fist
=flexion of PIP and DIP with no flexion of MCP
what position would allow for optimal glide of FDS
straight fist
=fexion of MCP and PIP but extension of DIP
what position would allow optimal glide of FDP
full fist (full flexion)
true or false: the full fist allows optimal glide of the FDS
false, FDP
hook fist allows optional differential glide of what
FDP FDS
straight fist allows optimal glide of what
FDS
full fist allows optimal flide of what
FDP
what are the extrinsic musculotendinous structures for extension and abduction
extensor digitorum communis (EDC)
indiex proprius
extensor digiti mini
extensor pollicis longus/brevis
abductor pollicis longus
what fingers have individual extensor tendons
indépendant active extension of the index and little fingers
true or false: active extension of the long and ring fingers is difficultt when the MCP joints of index and little fingers are flexed
true
what is the juncture tendinae
the tendons of the extensor digital to the fingers are connected to one another by the junctura tendinae
what is the function of the juncturae tendinae
increase extension to individual fingers
if one of two fingers passively flexed at MP, pulls EDC of other fingers along
what muscles make up the thenar eminence
flexor pollicus brevis
opponens pollicus
abductor pollicis brevis
adductor polices
what muscles make up the hypothenar eminence
flexor digiti minimi
opponents digiti minimi
abductor digiti minimi
what are the intrinsics of the hand
lumbricals and itnerosseus structures
explain the diamond of stack during flexion and extension
during flexion, diamondss is larger
during extension, diamond is tighter
explain boutineires deformity
disruption of central slip insertion (causes slip in the volar direction of the lateral bands)
=PIP flexion and DIP extension
why does MP flexion cause IP extension
because the lateral slips of the EDC tighten and pull the lateral bands
(flexion of MPs and etension of PIP/DIP)
EXPLAIN FINGER movement segment during digital flexion
extrinsic FDS initiates flexion at the PIP joint
extrinsic FDP then flexes the DIP joint
intrinsics then flex MP joint
explain finger movement segment during digital extension
extrinsic EDC extends MP joint
intrinsic lumbricals and interosseus muscles extend PIP and DIP joint
explain the tenodesis pattern
wirst Extension = finger flexion
wrist flexion = finger extension
what are the 3 functions of the retinacular system (flexor retinaculum)
prevent bowstringing of flexor tendons
maintains capral arch
optimizes flexor forces
what structure forms the roof of the carpal tunnel
flexor retinaculum
what needs to be cut open in carpal tunnel syndrome surgery
flexor retinaculum
what is the function of the extensor retinculum
functions as a pulley for the extensor tendons
maintains constant moment arm
what is the test for DeQuervains tendonitis
finklesteins test
what is the finklesteins tes
to test for dequervains syndrome
=wrist ulnar deviation and thumb flexion
what is dequervains syndrome
swelling of the tendons that run along the thumb side of the wrist and attach to the base of the thumb
(abductor pollicus longus and extensor polloicus brecvis)
1st dorsal comparement of the extensor retinaculum
what is the function of the the digital flexor tendon pulley system
prevents bowstringing
=increase torque and decrease excursion
how can a patient optimize FDS glide
make a straight fist
what are the fucntions of the pulley excision
there are 4 normal annular bullies facilitate normal flexion
what are the 3 most useful pulleys
a2, a4 and a3
what bands make up the diamond of stack in fingers
lateral bands
the lateral bands in the finger make up a shape, what is that shape called
diamond of stack
what three structures contribute to form the lateral and central bands of the fingers
EDC (extensor digi)
interossei
lumbricals
flexion of MCP and simultaneous extension of PIP/DIP relies mostly on what muscels
intrinsics (ex : lumbricals)
