hand and wrist Flashcards
how many muscles and bones are in the wrist and hand?
muscles = 19 intrinsic, 20 extrinsic
bones = 29
- radius/ ulna
- carpals
- metacarpals
- phalanges
what are the 3 parts of the distal ulna?
- ulnar styloid process
- fovea (attachment point for disc)
- pole (articular surface for TFCC articulation of the wrist on the ulnar head)
is the distal ulna in direct contact w carpal bones?
no
what is the primary forearm bone of the wrist?
distal radius - all weight and power goes through radius
is there more radial or ulnar deviation possible?
ulnar - bc w radial deviation scaphoid runs into stylus
where is lister’s tubercle and what does it do?
dorsal feature of radius
acts as a pulley, redirects pull for
for which muscles does lister’s tubercle act as a pulley?
radial side:
- extrinsic digitorum longus
- extrinsic indices
ulnar side:
- extensor pollicis longus
“digitorum” =
all fingers
“indices” =
only index
“pollicis” =
thumbs up
proximal row of carpal bones
scaphoid, lunate, triquetrum, pisiform (sesamoid)
distal row of carpals
trapezium, trapezoid, capitate, hamate
are metacarpal shafts curved?
yes - with palmar concavity
do the base or head of phalanges have a bigger articular surface?
head
shape of base and heads of phalanges:
base = biconcave
distal heads = biconylar
how many bones and joints make up the wrist complex?
15 bones
17 synovial joints
is the wrist very mobile? what secures the joint?
highly mobile, secured by many ligaments
what type of joint is the distal radioulnar joint?
uniaxial synovial pivot joint, 1 DOF
action of distal radioulnar joint:
pronation/ supination
what makes up the distal radioulnar joint?
TFCC
oblique fibers of distal interosseous membrane
radioulnar ligaments
TFCC
function?
triangle shaped on ulnar side
stability stops bones from being ripped apart
carpal tunnel
underpass for finger flexors to travel
- guides tendons, median nerve, protection for wrist
- syndrome: too much inflammation, scar tissue builds and binds down on nerve and vasculature
what type of joint is the radiocarpal joint?
DOF
motion
ellipsoid/ condylar synovial
2 DOF
flexion/extension, radial and ulnar deviation
midcarpal joint:
what type of joint is formed by the proximal and distal rows?
what type medially vs lateraly?*** ask rachael wtf
synovial plane joint
laterally = planar
medially = condylar
what gives palm its concave appearance?
arches formed by carpals, metacarpals, and ligaments
what motion do CMC joints allow?
transition from palm flat to fist
which CMC joints have the most least motion in order?
2<3«4<5
1st CMC
what type of joint/ why so much ROM in thumb?
synovial saddle joint
both concave and convex
thick but loose capsule
how many motions can the 1st CMC do? what are they?
6
flex/ex - girl scout/thumbs up
ab/duction - drawbridge/back to palm
opposition/ reposition
MCP joint
type
DOF
motions
synovial condyloid
2 DOF
flex/ex, ab/dduction
what extends the concave base of phalanges?
fibrocartilaginous volar plates
what covers MC heads?
3/4 covered w articular cartilage - extend into volar surface
IP joints
joint type
DOF
motion
synovial hinge
1 DOF
flex ex
*similar mechanisms as MCP
what happens to the volar plate as IP or MCP joints flex? what does this allow for? what does this prevent?
volar plate slide proximally under MC - folding of membranous part
allows for large ROM
prevent hyperextension and dorsal subluxation
wrist ligaments - where are extrinsic vs intrinsic
extrinsic - radius, ulna, metacarpas to carpals
intrinsic - between carpal bones only
