wrist osteology and arthrology Flashcards
where is lister’s tubercle located
dorsal radius
discribe the distal articular surface of the radius
concave in both ML and AP with facets in the articular surface
what is the ulna tilt and what is its importance
distal end radius 25 degrees toward ulna
allows more ulna dev than radial dev
why is radial dev less than ulna dev
carpals hit radial styloid process in radial dev
what is the significance of palmar tilt
10 degrees
allows for more flx than ext in wrist
what bones are included in the proximal row of the carpals
scaphoid, lunate, triquetrum, pisiform
what bones are included in the distal row of the carpals
trapezium, trapezoid, capitate, hamate
what row of the carpals is more tightly bound
distal row
bound tightly by strong ligaments
what type of joint is formed with the scaphoid and 4 other caprals
synovial
the proximal convex pole of the scaphoid articulates with what structure
radius
the distal convex pole of the scaphoid articulates with what structure
trapezium and trapezoid
the deep concavity of the scaphoid holds what structure
the small concavity holds what
capitate
lunate
t/f
the scaphoid is most frequently fractured carpal
true
t/f
the scaphoid is most frequently fractured carpal
true
what is kienbocks disease
softening of the lunate AVN
describe the lunate
moon shaped
central bone in proximal row
fits into radius
t/f
the lunate is the most stable bone of the carpal bone
false
the lunate is the most commonly dislocated bone
most inherently unstable d/t lack of strong ligaments in capitate with no muscle attachments
descibe the triquetrum
triangular bone
most ulnar just distal to ulna
articular facet that accepts pisiform
describe the pisiform
shaped like a pea
loose articulation with triquetrum
acts like a sesamoid bone
what tendon is the pisiform embedded in
FCU tendon
what attaches at the pisiform
abd digiti minimi, transverse carpal ligament
describe the capitate
largest, central carpal bone
articulates with 7 carpal bones
t/f
the capitate is well stabilized by short strong ligaments
true
what bone concavities does the capitate articulate with
scaphoid and lunate
describe the trapezium
asymmetrical
concave at scaphoid
distal saddle like surface
what attaches at the trapezium tubercle
transverse carpal ligament
describe the trapezoid
small
wedged between capitate and trapezium
firm attachment to 2nd metacarpal
describe the hamate
large hooklike process
located at base of 4/5 metacarpals
what attaches at the hamate
transverse carpal ligament
what is the functional mobility of the hamate
cupped hand
what is carpal tunnel made up of
what is its function
thick fibrous band of connective tissue - transverse carpal ligament
attachment site for man intrinsic muscles on the hand and palmaris longus
what are the 4 raised points that the carpal tunnel connects
pisiform
hook of hamate
tubercle of scaphoid
tubercle of trapezium
describe the radiocarpal joint
concave radius/disc and convex scaphoid/lunate
where is the highest contact of the radiocarpal joint
at slight extension and ulnar dev
describe the midcarpal joint
between prox and distal rows
continuous capsule
t/f
the midcarpal joint allows for more medial movement than lateral
true
how many intercarpal joints are there
13 joints
where are extrinsic ligaments of the wrist located
from radius or ulna
where are intrinsic ligaments of the wrist located
within wrist
____ surrounds wrist and distal radioulnar joint
fibrous capsule
t/f
no ligaments are embedded in fibrous capsule of the wrist
false
ligaments are embedded in fibrous capsule of the wrist
where is the triangular fibrocartilage complex (TFCC) located
space between pisiform/triquetrum, lunate, and ulna
how many degrees of freedom is in the wrist
what are they
2 degrees of freedom
flx-ext, ulnar-radial deviaiton
is wrist circumduction a 3rd degree of freedom
no, combo of flx/ext and ulnar/radial dev
where is the axis located of wrist movement
head of capitate
what is the plane of motion of wrist flx/ext
ML
what is the plane of motion of radial/ulnar deviation
AP
the rotation of the ___ directs the osteokinematics of entire hand
capitate
how many degrees is normal for sagittal plane motion of the wrist
flexion: 0-75/85
extension: 0-60/75
t/f
higher than average palmar tilt of radius does not affect wrist extension
false
higher than average palmar tilt of radius may limit extension
what are normal degrees of motion in the frontal plan for the wrist
radial dev: 50-60
ulnar deviation: 0-35/40 and 0-15/20
what range of motion is needed for wrist ADLs
flx/ext:
radial dev:
ulnar dev:
flx/ext: 40 degrees each
radial dev: 10 degrees
ulnar dev: 30 degrees
what motion naturally occurs with radial dev
wrist extension
what motion naturally occurs with ulnar dev
wrist flexion
describe the arthrokinematics of wrist extension
convex lunate rolls dorsally and slides in a palmar direction
head of capitate rolls dorsally on lunate and slides in palmar direction
describe the arthrokinematics of wrist flexion
convex lunate rolls palmar direction and slides dorsally
head of capitate rolls palmar direction on lunate and slides in dorsally
wrist arthrokinematics is driven by ___ but guided/controlled by passive tension within the ____
muscles
ligaments
describe the motions of the scaphoid, lunate, and triquetrum motion during ulnar dev
scaphoid, lunate, triquetrum roll in ulnar direction and slide radially
describe the arthrokinematics of the scaphoid, lunate, and triquetrum motion during radial dev
scaphoid, lunate, and triquetrum roll in radial direction and slide in ulnar direction
what joint is responsible for 80% of the motion of radial dev
MC joint
carpal instability is most commonly due to…
usually lax or ruptured ligaments
what is the most frequently dislocated carpal bone
lunate
what muscles are innervated by the radial nerve
all muscles that cross the dorsal side of the wrist
ECRB
ECRL
ECU
what muscles are innervated by the medial and ulanr nerve
all muscles that cross the palmar side of the wrist
FCR, PL - median
FCU - ulnar
what is the sensory innervation of the RC and MC joints
RC - C6, C7
MC - C6-C8
list the primary wrist extensors that act on only wrist
extensor carpi radialis longus
extensor carpi radialis brevis
extensor carpi ulnaris
list the secondary wrist extensors that act on the wrist and hand
extensor digitorum
extensor indicis
extensor digiti minimi
extensor pollicis longus
what secures extensor tendons in place
extensor retinaculum
what is de quervain’s tenosynovitis located
compartment 1
contraction of the extrinsic finger flexors flexes the fingers and creates a ___ ___ torque
wrist flexion torque
what muscles block the wrist flexion caused by activation of finger flexor muscles
wrist extensors
what is the length-tensor relationship of the wrist
wrist extensors maintain optimal length of the finger flexors to effectively flex fingers
maximal grip force occurs at about __ degrees of extension
30 degrees
what population most commonly has lateral epicondylitis
hammering
tennis players
what symptoms are common with lateral epicondylitis
painful/weak grip
pain with passive wrist flexion and pronation
tenderness over lateral epicondyle
list the primary wrist flexors
flexor carpi ulnaris
flexor carpi radialis
palmaris longus
what are the secondary wrist flexors
flexor digitorum profundus
flexor digitorum superficialis
flexor pollicis longus
abductor pollicis longus
extensor pollicis longus
what is the function of the palmar carpal ligament
stabilizes/prevents bowstringing
what muscle has the highest wrist flexion torque of all 3 flexors
flexor carpi ulnaris
what 2 muscles work together as synergists to oppose deviations
flexor carpi ulnaris and flexor carpi radialis
t/f
wrist flexors are able to produce 70% higher isometric torque than extensors
true
peak wrist flexion torque is at __ degrees flexion
40
peak extension torque is at __ - __ degrees of extension
30-70
what muscles act to radial deviate
extensor carpi radialis brevis
extensor carpi radialis longus
abductor pollicis longus
extensor pollicis longus
extensor pollicis brevis
flexor carpi radialis
flexor pollicis longus
what muscles act to ulanr deviate
extensor carpi ulnaris
flexor carpi ulnaris
flexor digitorum profundus
flexor digitorum superficialis
extensor digitorum
