Transcript Document

Paper Review
Contribution of the extrinsic and intrinsic
hand muscles to the moments in finger joints
Z.M. Li, V.M. Zatsiorsky, M.L. Latash
Clinical Biomechanics 15(2000)
學號：N16941703
學生: 洪振翔
指導教授: 朱銘祥
林宙晴
實驗室：人機系統實驗室
2007/05/29
Outline
•
•
•
•
•
•
Introduction
Goals
Methods
Modeling
Results
Discussion
2
Introduction(1)
•
Extrinsic muscles: originate outside the hand.
- responsible for the primary functioning in a variety of tasks
- extensor、flexor
•
Intrinsic muscles: originate and insert within the hand.
-provide necessary balance and fine tuning of the multi-joints system
3
Introduction(2)
•
In clinical practice the force of FDP is estimated
subjectively.
•
If we want to calculate the moments at the finger
joints in static conditions, both the magnitude and
direction of the external force must known.
•
In this study, a novel measuring system (the
suspension system) was developed.
4
Goals
•
To develop a method of estimating force produced by
the flexor digitorum profundus (FDP), flexor
digitorum superficialis (FDS) and intrinsic muscles
(INT).
•
To estimate the contribution of these muscles to the
finger joint moments.
5
Methods
•
Apparatus
-the suspension system
•
Ten right-handed male
•
Experimental procedure
1. three location
-ExpDP, ExpDIP, ExpPIP
2. press down maximally
-the interphalangeal joints are fully extended
3. EMG of EDC
(extensor digitorum communis)
6
Modeling(1)
•
Finger joint moment
DP
 M DIP
 DIP
M   M DIP
PIP
 M DIP

DP
M PIP
DIP
M PIP
PIP
M PIP
DP

M MCP
DIP 
M MCP

PIP 
M MCP 
 DP LDP

DP LDP
DP LDP
P
(
)
P
(

L
)
P
(

L

L
)
IP
IP
PP 

2
2
2



0
P DIP ( LIP )
P DP ( LIP  LPP ) 


0
0
P PIP ( LPP )




where M kj is the moment at joint j produced by external force Pk
•
Muscles counterbalancing an external finger moment
at the joints at different loop positions
7
Modeling(2)
•
Analysis of muscle forces and their contribution to
joint moment
8
Results(1)
•
Contribution of muscle groups to joint moments
For ExpDP,
DP
DP
CFDP

C
, PIP
FDS , PIP  100%
For ExpDP,
DP
DP
DP
CFDP

C

C
, MCP
FDS , MCP
INT , MCP  100%
For ExpDIP,
DIP
DIP
CFDS

C
, MCP
INT , MCP  100%
9
Results(2)
•
Muscle forces
The maximal forces produced by individual muscles depended
on the experimental condition.
10
Discussion(1)
•
The “suspension” design in this study is advantageous
in that the orientation of force application can be prespecified.
•
In this study the fingers were extended and the force
was applied at the middle of the distal phalanx which
might be similar to the pulp pinch posture.
•
In the model, the contribution of the INT to the
extensor mechanism at the PIP and DIP joints was
neglected.
11
Discussion(2)
•
The dorsal and palmar interossei and lumbricals were
lumped together and viewed a single muscle that
produced a moment solely at the MCP joint.
•
The assumption is justified because in the
experiments the fingers were extended.
•
As a result, the effects of extensor mechanism are
relatively small when the point of force application is
at distal position.
12
Thanks for your attention
13