Hand packet 1 Flashcards
Digital ray
1 metacarpal & 3 phalanges
only 2 phalanges in thumb
joints of the fingers
1 cmc joint
1 mcp joint
2 ip joints
joints of the thumb
1 cmc joint
1 mcp joint
1 ip joint
total # of bones in the hand
19 bones
digits 2-4 (@ CMC jt)
how many degrees of freedom?
1 DOF
flexion/extension
articulations of the 2nd finger are with:
@ CMC jt
trapezoid
trapezium
capitate
3rd metacarpal
articulations of the 3rd finger are with:
@ CMC jt
capitate
2nd metacarpal
4th metacarpal
articulations of the 4th finger are with
@ CMC jt
hamate
capitate
3rd metacarpal
5th metacarpal
articulations of the 5th metacarpal are with
@ CMC jt
hamate
5th metacarpal
5th digit DOF
@ CMC jt
2 DOF
- flexion/extention
- abduct/adduct
5th digit flexion ROM
@ CMC jt
10-15 deg
5th digit abduction ROM
@ CMC jt
20-30 deg
most mobile CMC joint is at which digit? (not incl thumb)
5th
but they are the least stabile
least mobile CMC joint is at which digit? (not incl thumb)
2nd & 3rd digits
but they are the most stabile
function of the CMC joints are to
form palmar arches
function of palmar arches
- to permit optimal function of the hand
- allows the hand and palm to conform to an object
anatomy of the palmar arch
2 transverse connected by a longitudinal arch
proximal transverse of the palmar arch
- relatively fixed
- level of distal carpals
keystone of the proximal transverse of the palmar arch
capitate
distal transverse of the palmar arch
- more mobile
- level of the metacarpal heads
keystone of the distal transverse of the palmar arch
3rd metacarpal
longitudinal palmar arch consists of
4 metacarpals and proximal carpals
carpal tunnel consists of
carpals flexor retinaculum transverse carpal ligament 9 tendons Median nerve
9 tendons of the carpal tunnel
4 FDS
4 FDP
1 FPL
purpose of the flexor retinaculum (that helps form the carpal tunnel)
supports the flexor tendons so they do not bow
arch integrity is maintained by
bones
ligament
intrinsic muscles of the hand
median nerve innervates the lumbricles at
2 lateral muscles
ulnar nerve innervates the lumbricles at
2 medial muscles
palmar and dorsal interossei are innervated by
ulnar nerve
MCP joints 2-4 have ____ bases of first phalanx on _____ metacarpal heads
concave on convex
same direction
how many degrees of freedom in the MCP joints 2-5?
2 DOF
flexion/ext
abd/adduction
the fake 3rd degree of freedom in MCP joints 2-5??
rotation –
really a combination movement of:
pronation/supination
&
abduction/adduction
volar/palmer plates
- fibrocartilage plates
- multilayered thickening of the inside capsule
- distal MET –> base of the proximal phalanx
volar/palmer plates proximally are:
membranous (blends with the capsule)
volar/palmer plates proximal motion is
gliding of the plate with finger flexion
volar/palmer plates blend with
transverse metacarpal ligaments
volar/palmer plates are stabilized by
collateral ligaments
volar/palmer plates resist
hyperextension
injury of the volar/palmer plate
- caused by hyperextension
- subluxation and dislocation occurs
- may even cause a velar plate tear (at the membraneous portion)
treatment for velar/palmer plate injury
immobilize MCP in relative flexion
- retract the membranous tissue
- flexion contracture
MCP flexion ______ as you move _____
increases;
ulnarly
MCP ROM
90 - 110 deg
MCP abduction/adduction is maximal in
extension
MCP abduction/adduction is minimal in
AND WHY??
flexion
close-packed
-because of:
taut collateral ligaments & because of bony block secondary projections on MC head
Passive support for MCP
joint capsule
volar plate
collaterals
MCP joint capsule is:
_____ in extension
_____ in flexion
slack;
taut;
MCP collaterals are:
_____ in extension
_____ in flexion
slack;
taut;
No Man’s Land
- an anatomical region (over the metacarpal heads)
- In the past, the primary repair of flexor tendons was contraindicated – no surgery here bc repair & rehab was too complex
Now: surgery is performed but early mobilization = crucial
IP joints have a _____ head with a _____ base
convex;
concave
IP joints have:
volar fibrocarilagenous plate
joint capsule
collateral ligaments
how many DOF do IP joints have
1 DOF
flexion/extension
PIP joint ROM
100 - 110
DIP jt ROM
80 deg
_____ movement at PIP than DIP
more
IP ROM increases _____
ulnarly
5th PIP flexion ROM
135 deg
5th DIP flexion
90 deg
IP joints function
- enhances closure
- improves grip along with mobile 5th CMC
fingers are designed to function in
flexion
–therefore they’re super stong
thick anterior capsule of the fingers is ???
palmer plate
dorsal capsule is ___ & ____
thin & lax
wrist extension function
maintain optimal length-tension relationships
weak wrist extension (ECRB or ED) causes
flexion of the wrist rather than finger flexion
—– LESS finger flexion than you would have when the wrist is flexed
finger flexor efficiency drops by _____ when the wrist is in extension (due to weakness)
75%