Download THE MOVEMENTS OF BONES AND JOINTS Function of the

THE
MOVEMENTS
OF
Function
2.
M. A.
From
Muscles
retain
position
for
another
influenced
by
that
which
not
is
simply
The
The
shunt
“
of
in the
while
during
movement.
nineteenth
while
These
century.
spurt
“
is the
“
is possible
to
anatomical
arrangement.
words
were
distinguish
shunt
SHUNT
A shunt
muscle
is one
across
it ; whereas
distinction
becomes
that
in which
the
bones
make
an
the
joint
is inserted
far
from
which
arises
if any,
This
far from
muscles
the
with
even
for
rule.
The
most
posterior
spurt
ischial
muscles
joint
origins
is true
to the
spurt
into
of
the
function
“
by
muscles
its
the
; the
phasic
action
are
it is clear
the
joint
of their
two
that
kinds of muscle
above
it remain
pubic
by
more
English
simple
fibres
and
that
the
difference
origins
and
insertions.
is, of course,
more nearly
(Fig.
The
the
along
muscle
are
in the
of their
two
types
for the
than
There
are
they
act.
to be an exception
whereas
the
brachialis
anticus
shunt
muscles.
From
is the
relative
the joint
do those
most
are
these
distance
from
action
of the
in main
that muscles
whose
length
beyond
parallel
to the moving
bone than
near
a muscle
very few,
which
muscles,
distinction
The
to
arises
hand,
on
appears
the
bone
which
other
joints
and
are
the
than along
it.
of full extension
muscle.
spurt
brachii
these
reason
the
the
at first
brachio-radialis
The
descriptive.
engineers
A muscle
On
from
biceps
between
1).
muscle.
which
of this
is
muscles
inspection
force
to it is a spurt
muscle,
muscles.
teres
other
near
functions
of the
MUSCLES
equidistant
magnus
shunt
pronator
examples
is inserted
in a field
with movement
in a curve,
curve.
As a general
rule it
contractile
a shunt
insertions
adductor
are
each
with
it is clearly
and
and
anterior
fibres
angle
change
out
bone in the direction
of the joint,
the curved
path which
it traverses
SPURT
more
and
and
mechanics
spurt
or they
is carried
a spurt
muscle
directs
more of its force across
the bone
effective
as soon as the joint moves
from the position
one
and
postural
“
AND
directs
between
force associated
tangent
to that
from
MUSCLES
function)
functions
along
the
bone along
introduced
muscles
(postural
arrangement
Shunt
“
is the centripetal
force which
acts along the
“
Cork
of these
and
“
College,
position
distinction
function
IRELAND
University
Each
refers
to the force which
is transmitted
spurt refers
to the force which
pulls the
JOINTS
Musculature
in a given
it is reflected
AND
CORK,
function).
gravity.
terms
the
Department
of a joint
(phasic
for
of
MACCONAILL,
A natomy
bones
academic,
themselves.
Shunt
the
the
BONES
is greater
than
of the opposite
type,
and thus direct
more of their force along the bone.
It is possible
to develop
the thesis
in a mathematically
precise
manner
(MacConaill
1946) ; but this is not necessary
for the
practical
grasp
and application
of the principle.
This principle
finds two chief applications,
namely,
interosseal
parts
a
mechanical
expansions,
basis
which
explains
and an understanding
of the
musculature
The
more
sheaths
transmit,
that
the
100
clinical
than
serve
importance
bursae,
the
FUNCTION
of tendon
ancillary
simple
close against
“vaginate”
and
lumbricoof the several
of joints.
THE
no
the
sites
of tendon
sheaths
of the sequence
of contraction
purpose
to
OF
synovial
the
fibrous
of retaining
the bone in all positions
muscles,
as we may call
TENDON
SHEATHS
sheaths
has
sheaths
the
obscured
beneath
tendons,
the
which
and
fact
they
therefore
that
they
run.
the
are
Fibrous
forces
they
of the joint.
The effect
of this function
is
them,
are shunt
rather
than
spurt
muscles,
THE
JOURNAL
OF
BONE
AND
JOINT
SURGERY
THE
except
the
for
digit
the
joints
in the
at
case
which
of the
the
explanation
It makes
the
art
not
longus
BONES
AND
digitorum.
of
ballet
example,
This
LUMBRICAL
ankle
and
wrist
dancer
and
the
AND
is shown
The
the
instinct
sheaths
perhaps
deeply
more
shocked.
in Fig.
joints
over
sheath
and
1
FIG.
Scheme
between
proximal
examination
extensor
than
that
candidate
is less
entitled
to show
Spurt
and
the
difference
shunt
muscles.
The spurt
muscle
(A) pulls
more
directly
across
the bone
in most
positions
other
than
full extension.
The shunt
muscle
(B) pulls
more
directly
along
the
bone.
to the
paper
by
pull the
direction
the
a sheath
Sunderland
(1945),
CISARTICULAR
The
distance
movement
from
of a joint
the
may
AND
origin
made
are
the
-is
(Fig.
the muscle
The ratio
When
muscle
muscle
that
A in Fig.
; but if the
then
proof
the
the
axis
length.
to
is primarily
(MacConaill
ratio
has
a special
part
and
upon
cases
and
to the
and
this
action
will
than
be
The
application
VOL.
31 B,
NO.
is enhanced
1,
FEBRUARY
are
lumbrical
inserted
into
These
the
expansions
postural
the
bulk
mechanism
of the
limb,
of the
and
they
from
axis
its full
length
to
concept
muscles
the
B
the
‘I
the
this
Hence
by
enclosure
in
1949
there
muscle
behaves
Where
there
muscle,
two
it is a shunt
a synovial
to show the
of a fibrous
Where
author’s
over
2
FIG.
Scheme
action
Further
passing
to it.
of war.
of
in
underlying
far distal
theatre
natural
(C) to
as
muscle.
in
Pacific
the ratio
CIT
muscle
to the
unity,
found
the
length,
the insertion
of
These
measurements
a shunt
1946).
is inserted
the
LENGTHS
is
but
formed
a
joint-stabilising
tendon
sheath.
sheath
(A) the
a spurt
muscle.
sheath
bound
elbow
(its
by
joint,
the
bones.
muscle.
on the
above
to the
the
the
action
distance
muscle
(B),
to
as a shunt
a short
or postural
sheath
as
being
on the
no
is
behaves
joints.
The biceps
brachii
may be taken
as an example.
It is a muscle
which
acts upon the shoulder
j oint and also
radio-ulnar
j oint is irrelevant
to this discussion).
It arises
shoulder
say,
of the
they
of the
digits
cisarticular
is stretched
to
of the cisarticular
is greater
statements
who
is
why the
extensor
in a palmar
(or plantar)
the tendon
in close apposition
with
1, then
the muscle
is primarily
a spurt
ratio be less than unity,
as in the muscle
muscle
of these
paper
ratio
than,
tendon.
TRANSARTICULAR
transarticular
length
(T)-that
is to say,
a guide to the functional
relation
of the
joint.
B,
while
3).
based
of a muscle
be called
and the distance
from
that
muscle
is the transarticular
length
posture.
joint,
is to be
at the correspondfunction
served
by a
by expansions
extensor
form
the
of
of the examiner
who cannot
see
where
of the
They
between
range
candidate
who assigns
tendons
of the fingers
is
to
also
muscles
tendon
of the
and thus keep
bone.
joints
rather
than move
phasic.
In this
enable
the fingers
(or toes)
to be used
effectively
over a
wide
range
of posture.
Attachments
to the more
distal
a similar
function
at the joints
of the fingers.
For a first-hand
nerve
injury
upon
the functions
of these
muscles
the reader
is
parts
of the tendon
subserve
account
of the effects
of
referred
is served
parts
of
MUSCLES
sound
The
interosseous
joint
2.
a wide
flexor
beneath
a metatarso-phalangeal
forgiven,
because
the range of angulation
ing joints
is comparable.
In fact, the
flexor
terminal
acrobat.
of the
to the
index-extensor
the
bones together
rather
than
INTEROSSEOUS
tendon
101
JOINTS
ensheathed-for
muscles
tend to press
than
mobilisers-postural
stability
of the
THE
OF
are
shunt
rather
of the
possible
they
flexor
It will thus be clear that
them.
They
are stabilisers
lies
MOVEMENTS
the
shoulder,
and
by
102
the
M.
prolongation
of the
sheath
along
the elbow
and is inserted
but
spurt
or phasic
muscle
for the elbow.
to other
muscles
which
are disposed
long head of the biceps
femoris
had
of the
knee,
acts on two joints
and
We
a spurt
THE
bicipital
groove.
are
muscle
led,
then,
to one and
REVERSIBILITY
OF
MUSCLE
at the
joint.
cisarticularlength
(T) of a muscle.
of
the
joint
the spurt
interchange
musculature
for
muscles
tendons
(C)
See
The
influence
environment
; and
assessment
lifting
is a constant
of muscles
power
measure
factor
must
THE
The
magnitude
of this
direction
a bone
of its conof movement
moment
of contraction
an
added
loads
put
in attempts
they So actfar from
as spurt
the
muscles
are therefore
shunt
action
is not
their
cisarticular
and
those
which
exceptions,
have lumbrical
it appears
that
and
reserve
efficiency.
power,
than
the
load,
is one
of the
the
for any
in
action
which
given
of a parallelogram
load.
at
varies
We
of forces
time
; it
with
the
have
thus
which
if the ratio J/W were known,
respectively.
The law which
underlies
balances
the pull of gravity
whether
acts
at
total
load,
the
directional
could
I
k
FIG.4
‘
,
,
The
-
parallelogram
of
forces
of a joint
at rest
(or moving
at minimal
uniform
speed).
‘
(W) Total
load
(weight
oflimb
plus extraneous
forces
all
forces
MUSCULATURE
Weight-
rather
towards
the centre
force is the resultant
of gravity
the
upon
them.
at numerical
which
have
a resultant
directed
the joint
(Fig. 4).
The other
muscle
is
of
in our
two
without
to scale
in moving
overcome
or
lines
a muscle
the limb.
The weight
of the
may
often
be comparable
force
the
TO
analogous
upon
the
of squint.
limb, with
is fixed
: when
the shunt
effect
when
they
act from
they
act from
anatomical
insertions.
and conversely.
This
restriction
absolute
force,
of the muscles
and are thus
to the tests
which
an ophthalmologist
makes
oculomotor
apparatus
of a patient
suspected
In all important
cases the weight
of the
centre
of a muscle
tendons,
nor for
Apart
from these
GRAVITY
of gravity
of muscular
tests
OF
the
the maximal
extraneous
fact has to be kept in mind
This
have sheathed
into them.
RELATION
this force as well as move
parts
moved
by muscles
with
rule
muscles
which
are prime
movers,
and shunt
muscles
which
are joint approximators,
their
roles with reversal
of their
directions
of contraction.
That
is to say,
of a joint
is mechanically
reversible
as a whole,
but not by parts.
THE
far
to the other.
action
is concerned,
the
reversible.
But
their
reversible
; for in general
is indicated.
which
inserted
it arises
ACTION
of the
transarticular
lengths
are unequal
; and the greater
anatomical
origins,
the less will be that
effect
when
The cisarticular
length
then
becomes
the transarticular,
does not hold
and interosseous
general
the
origin muscle
or fromfibres,the whether
insertion.
3
.
hand
solely
upon
the moment
force taken
about
the axis
independent
FIG
other
muscle
effect
depends
tractile
meaningsof
length
of motion
the
to this
a shunt
The
To illustratethe
and
transarticular
text.
The axis
On
a short
distance
distal
to it. It is therefore
a powerful
The example
of the biceps
brachii
is extended
readily
similarly.
In particular,
Haines
(1934)
showed
that
the
little
phasic
effect
upon the hip joint
when
it acted
as
conversely.
it is chiefly
MACCONAILL
the
above
a motor
A.
of
of
the
but
of moving
part
load).
(M) Muscular
force
required
to keep
the part at
rest,
shown
acting
through
centre
of
gravity
of the
moving
part.
This is the
resultant
of all the actual
muscle
forces
in operation.
(J) The resultant
of the
other
two forces,
acting
across
the
joint.
It is shown
in the text
to be equal
in
magnitude
to
the
total
load.
be drawn
J
and W being the total shunt
the concept
of this parallelogram
the joint
be at rest or in uniform
THE
JOURNAL
OF
force
and the total load
is that musculature
motion.
BONE
AND
JOINT
SURGERY
THE
limb
It is an anatomical
is not retained
say,
the
has
will be
amount
the
fact that
automatically
centripetal
curve,
to
MOVEMENTS
or shunt
be
supplied
which
the
AND
structure
assistance
must
In
constant
during
uniform
movement.
will be proportional
to the square
of a joint is such that
of muscles
is required
be present
musculature.*
103
JOINTS
so far
when
we have
as this
is true,
In accordance
of the rate of turn
the swinging
: that
is to
movement
the
along
shunt
a
J,
force,
with
the laws of physics
the
of the bone about
the axis of
joint.
then
What
equal
to the
of the
and
is the
J
of
when
the
joint
large
tonus
arc
at
is present,
the
part
is on
the
same
rate
and
the
swing.
That
is, in the limit,
to the load (W) and is constantfor
It follows
that
when
the weight
joint,
as in the upraised
forearm
muscles
will be in minimal
action.
rehabilitation
of cases of infantile
agreement
argument.
between
Further
traction
of the
expectation
evidence
several
Let
bone,
rest
that
force
centripetally
rapid
be
the
require
place
of surface
his
hands
his elbows.
of marked
reversed.
first
case
are
anti-gravity
31 B,
looked
and
the
typical
for
in
each
be
added
free
“)
top
For
practical
NO.
1, FEBRUARY
a
the
upon
is
the
of the
of con-
musculature
the
be the
of
the
the
of a joint
joint
force
along
the
which
acts
joint.
bone.
Any
more
That
force cannot
along the curve as
of the movement.
nature
muscles
The
is most
experiment
of a door
the
is much
summarise
muscles
name
force
the truth
sequence
acceleration
shunt
case.
brachio-radialis
The
the
can therefore
as the
*
the
the
uniform
; that
difference
easily
is to
then
to
the
in positions
implies,
have
purposes
the
1949
ease
aided
by
pull
rOle of the
other
a special
say,
arc
of movement
nearly
may
play
be
the
those
subject
the
by
complete
regarded
that
extension
swing
at the
to
bending
in advance
have
been
a moderately
by saying
of
expect
subject
slowly,
contraction
raise
in rapid
order
would
marked
contraction
and shunt
muscles
musculature
to
asking
up
of muscular
the
than
part
as one
by
himself
of observation
making
between
observed,
is to be checked
and
that
We
also
are
by the
It
“
or shunt
downwards
movement
will then be seen to come into
biceps,
for the roles of spurt
weight.
muscles,
uniform
is excluded
available
be
say,
should
to
inward
It will
The brachio-radialis
contraction
of the
(forearm
over
is proper
is considered.
joint.
an
for
possibility
anatomy.
upon,
the
proper
joint
than
the prime
movers.
Thus
we should
expect
that
the
teres,
and the brachio-radialis,
would
come into increased
conthis can easily
be felt and seen to be the case.
These four muscles
to some
extent
throughout
the movement
; it is an increase
of
origins
on grounds
of the
impart
only
is to
its
be moved
as
towards
would
The
biceps
can
and
has
“
force
that
they
This
which
joint
directed
along
muscles,
of the
and
a force
to act
bone.
contraction
is true,
give
force
spurt
contraction
above
to
shunt
the
closer
to the
biceps,
brachialis,
pronator
traction
in that order,
and
are, of course,
contracted
be
CONTRACTION
possible
the
with
it may
swing,”
pendulum
“
movements
slowest
by
are
known
a greater
as one along
which
pendulum
“
not of itself
demonstrate
nature
is available
if the
for all positions
well
muscles
that
possible
degree
of tonus
arm is hanging
vertically
centripeta.l
MUSCULAR
stated
gravity
the
will
of
to W. This
arc, but the
the same
with
OF
law
same
throughout
movement
provided
the
with
being
It appears
or on the ankle
in standing,
the prime
movers
or spurt
This is well known
and has been applied
admirably
to the
cerebral
palsy by Phelps
and his school
(Collis
1947).
This
concerned
that
combines
?
is a minimal
When
the
when the joint is at rest the
all positions
of the joint.
of the part
is acting
vertically
SEQUENCES
it be assumed
is at
with
and event
does
of a confirmatory
muscles
THE
which
moving
threshold
is equal
a small
therefore
pendulum
equal
is not
load,
musculature,
this
value
W. The argument
is thus : there
consistent
with security
of the joint.
total
centripetal
force which
balances
the weight
rate of swing.
A pendulum
swings
through
VOL.
BONES
the form and
; the active
force
by
OF
spurt
; while
joint.
as the arc of a circle.
in the
heavy
muscles
shunt
104
M.
It is understood,
at the
start
than
inhibition
out
upon
of course,
of the
of the
the
that
movement.
MACCONAILL
moving
Very
the
often,
antagonistic
experimenter
A.
fibres.
himself.
limb
such
An
against
gravity
acceleration
seems
experiment
Practise
calls
to be
is instructive
relaxing
the
for
acceleration
gained
by
muscles,
no
more
be carried
those
of the
; it has
to
especially
upper
limb : in particular,
let the arms hang heavily
by the sides ; sit-or
better,
stand-with
the two arms hanging
by the sides in that way ; now
let them bend
at the elbows ; do not
even
try to
bend
them
actively.
If the shoulder
muscles
be relaxed
completely
the
forearms
will be felt to
float
upwards,
much
as if they were floating
in salt water.
The
“
“
“
sensation
is remarkable
attain
considerable
fixed
upon
“
and
quite
angulation
a distant
different
of
object
so
the
that
from
elbow
the
that
in
increase
the
rOle
and
finger
the
elbow.
in the
of shunt
muscles
flexors
utmost
This
account
in which
the
and
value.
which
concept
been
purpose
statements
of spurt
has
of
the
be
have
two
part
at
be seen
in
if
others
a slight,
shunt
to have
but
demonstrate
of the
wrist
musculature
of muscular
of muscular
all
be
tone
of the
of the synovial
will
psychological
will
survey
aspects
be
experiments
preliminary
are
to
if possible,
normal
There
The
increases
served
of fresh
the
mechanism
not
been
grounds
from
It is possible
should,
exhaustive
to
or
flexion.
eyes
clenched.
these
muscles
chiefly
lightly
will
the
and
an
shunt
The
elbow.
fingers
to the
given
either
writer
upon
and
been
fists
of the
elbow,
to
way.
detachment
the
the
an introduction
treated
made
clenching
over
intended
than
Attention
have
The
pass
is not
as no more
of flexion
; for
which
intended
speed
of deliberate
this
concomitants
of cubital
flexion
may be attained.
The experiment
may be repeated
with
the
perceptible,
“
“
of
action
joints,
; it
a particular
relevance
arrangement
and
standard
works
upon
are
stimulated
to
is
a mechanism
action
the
subject.
question
the
experiment.
SUMMARY
1 . Muscles
displacement
acting
upon
any
or spurt
muscles,
2.
which
Muscles
shunt
muscles.
3. The fibrous
arise
far
tendon
4.
The
lumbrical
5.
The
arrangement
joint
and
from
sheaths
and
can be
muscles
the
are
muscles
musculature
joint
cavity
during
movement
is supplied
rest or
mainly
uniform
by the
6.
described
are
are
to
spurt
joint-stabiising
interosseous
of the
Experiments
joint
divided
into
of stabilisation
muscles
; those
which
: muscles
arise
near
of
it
are
mechanisms.
are
muscles
is such
these
of stabilisation
as to
movement.
shunt
muscles.
illustrate
two principal
groups
or shunt
muscles.
ensure
The
of the
a constant
necessary
digits.
pressure
centripetal
across
force
the
during
observations.
REFERENCES
(1947) : Reablement
of Children
with
Infantile
R. W. (1934) : On Muscles
of Full
and of Short
MACCONAILL,
M. A. (1946) : Some
Anatomical
Factors
Irish Journal
of Medical
Science,
6th series, 160.
COLLIS,
E.
HAINES,
SUNDERLAND,
Muscles.
S.
American
(1945):
The
Journal
Actions
of Anatomy,
of the
77,
Extensor
Cerebral
Action.
affecting
Digitorum
Palsy.
Lancet,
Journal
the
H, 239.
of Anatomy,
Stabiising
Communis,
69,
20.
Functions
Interosseous
of
and
Muscles.
Lumbrical
189.
THE
JOURNAL
OF
BONE
AND
JOINT
SURGERY