THE
1.
MOVEMENTS
Fundamental
Principles
with
M.
From
The
that
mechanics
bones
account
of
are
rigid
of the
other
the
circumstances
will
ask
how
how
far
they
and
how
far
would
will
the
he
constitute
a true
study
directed
chiefly
to
of
have
been
the
are
which
have
first
type
and
how
articulating
and
are
brought
because
anatomist
far
of the
and
second;
spinal
parts.
cord,
Such
subsequent
most
solely
are
brain
been
depend
orthopaedic
of the
In this
these
fact
and
often
unobserved
An
of the
for
in
fact
takes
surfaces,
have
movements
been
the
other
joint
parts
in which
control
shape
joints,
two
unsuspected.
the
upon
; the
of the
The
muscles
of the
depends
thickness
ligaments
mechanics.
synovial
: one
and
manner
under
special
of articular
the
parts
Cork
shape
or
of the
forces
by
two
character.
muscles
studies
by
Cottege,
breadth,
actions
them
about
conditioned
orthopaedic
for
movements
brought
they
to
Movement
EIRE
musculature,
regardless
synergic
call
are
be
the
certain
into
length,
individual
ascribed
JOINTS
to Rotation
University
divided
of the
its
matter,
which
are
be
CORK,
A nato;;zj’,
definite
joint
been
of dead
far
can
arrangement
Conversely,
the
of
AND
Reference
MACCONAILL,
having
the
have
mechanics
about.
j oint
any
give
Effects
upon
A.
BONES
Particular
Department
bodies
which
confused.
the
particular
features
OF
analysis
articles
frequently
attention
of concern
to
surgeon.
Movements
and
examining
our
displacements-Let
patients
permit
these
movements.
ment
is rather
more
us
The
simple
define
then,
: displacement,
distinction
than
the
movement
will
be
is not
as
what
hair-splitting
mechanics
what
takes
we
place
; for
of displacement
at
the
observe
the
when
joints
mechanics
and
is at
which
of move-
first
more
easily
understood.
KINDS
There
are
adduction,
used
in
the
one
joint
an axis
which
absolute
intervenes
swings
best
we may
by
1)
call
performing
Conjunct
an account
side
that
Take
an
arrow
with
the
head
a parasagittal
out
the
2)
Swing
to
3)
say
prevent
bring
Swing
at
Irish
The
(Fig.
upper
the
first
been
This
is clearly
arm
is now
abducted
so
other
and
a rotation.
Since
object
arrow
forearm
the
is to
external
in rotation
one
other.
No
rotation
The
working
upon
the
similar
this
of
synergic
about
seem
shown
to
that
action
with
can
experiment
be
two
of
the
successive
be appreciated
Let
the
is adapted
from
1946a).
right
tail
upper
and
its
and
is to be kept
is semi-pronated
In
turns
would
be
conjoined
(MacConaill
form.
forwards
surface
rotation
sense
rotation.
shoulder.
description
Science
joint
unless
of conjunct
living
in the
(lateral)
it will
is, as it were,
extension,
understood
distinction
Nevertheless
rotation
Flexion,
be
limb
hang
The
arrow
backwards.
in this
by
position
the
lies
in
through-
1).
upwards
the
the
and
flexion.
backwards
because
of
pointing
anatomical
in
to
2) rotations.
and
by
this
rotation.
and
rotation
; but
‘ ‘
experiment
limb
in
the
accompanied
it.
or some
term
(medial)
the shoulder-The
Journal
of Medical
of the
it into
arrow
general,
it conjunct
experiment
The
322
in
to
The
perpendicular
a swing
are,
plane.
the
upon
‘ ‘
between
: 1) swings,
swings.
is internal
slides
a simple
rotation
in the
all
room-that
or
MOVEMENT
of movement
are
surface
swings
muscles
kinds
is normal
as
successive
chief
abduction
dissecting
swings,
so
two
and
OF
in the
same
order
to
plane
as
plane
bring
until
arrow
horizontal
position
scapular
in
forwards
The
it
and
it
would
it is in
is now
until
the
have
then
rotated
back
into
THE
a horizontal
pointing
arrow
been
its
plane;
vertically
is in the
if
the
that
is
upwards.
scapular
pendent
plane.
limb
had
laterally
through
a right
angle.
original
pendent
position,
with
JOURNAL
OF
BONE
AND
JOINT
SURGERY
THE
the
arrow
plane
pointing
but
also
The
forwards,
medially
result
followed
of the
of the
shoulder
followed
flexion
have
of the
been
is a general,
let
the
by
the
forward
bearing
into
rather
than
experiment
Having
the
whole
5)
Repeat
the
6)
Verify
that
of
the
with
7)
the
becomes
the
scapular
flexion
of the
shoulder
shoulder
conjoined
be shown
that
horizontal
plane
free
upper
the
latter
scapulo-humeral
the
of
is the
equivalent
limb.
These
being
Such
with
abduction
but
study
neither
shows
movements.
facts
concerned
ligaments,
matter.
of articular
at
the
in
that
it
First,
however,
pendent
position
unless
the
limb
the
to
acquired.
3 on
once
shoulder
jointtile
experiment.
adduct
it has
1 to
impossible
the
it can
(1937),
experiment,
repeated
in
end.
which
be
the
rotation
described
of operations
can
adducted
that
of
of the
Johnston
proper
be
saying
in the
rotation
of
Conjunct
positions
six
arm
phenomenon
its
to
manoeuvres
geometry
rotation
cycle
abduction
of the
1 to 3 of the
lateral
cycle
shoulder
the
the
laterally
only.
the
A
rotated
stage
is
is
rotated
limb
limb.
reached
when
medially
full
flexion
pan
passz
flexion.
Bring
then
stages
undoing
by
of
and
323
JOINTS
have
summarised
tension
to
1-6.
first
only
medial
(1910)
AND
angle.
similar
with
continued
completed
without
By
fundamental
Figs.
the
4)
be
an exceptional,
be
not
a right
swing
upon
the
would
limb.
Fick
BONES
equivalent
conjoined
by
adventured
is the
upper
shoulder
with
writer
free
discussed
especially
limb
may
swing
rotation
OF
through
experiment
backward
lateral
of
the
rotated
of the
by
MOVEMENTS
the
limb
attempt
flexion
diminishes
with
flexion.
Show
medial
rotation.
the
it
VOl..
30 B,
that
NO.
to
of
the
the
2,
to
1948
original
shoulder.
of
this
double
MAY
its
amount
that
If it is possible
upon
back
lateral
limitation
secure
cycle
position
(i.e.,
Observe
rotation
holds
a ligamentous
of
that
movements
stage
the
1 above).
amount
imposed
also
when
preparation
(1
to
upon
the
limb
of the
6 above)
Rotate
of flexion
the
limb
is
about
and
is permitted
before
subjected
scapulo-humeral
brings
it laterally
which
attempting
to
joint,
a twisting
previous
verify
and
324
M.
tightening
of the
still.
Show
the
of
that
scapula)
The
part
a similar
along
a
Fig.
Consider
and
the
until
this
arrow
I)e
rotated
be
to
90
UI)
Plishel
the
arrow
during
for
from
\\‘
tO
effect
of
tvo
curved
in
the
would
S.
the
along
\‘ay
S\\’-\\’E,
common.
J)ath,
and
is
la’,
that
namely
l)\’. rotation
us
this
and
The
stated
bone
about
is
ap)liec1
a minor
corollary
the
all
of
(leals
with
of
this
point
have
of view,
Again,
the
one
of
the
equator
south
until
pole.
the
Imagine
arrow
arrow
at
which
rotation
with
meridian
E will
has
has
been
been
accom-
the
upon
two
path(\V)
in
a diadochal
a
diadochal
arrow-sphere
working
long
ways:
point
The
the
of
a general
FIG.
is accompanied
axis
unless
the
of course
rotation.
rotation,
i)iadochal
panie(l
since
it
7
movement
rotation
by
Let
movement.
SE-EW,
of
the
conjunct
about
isthe accornbone
of
its
long
axis.
what
is
is
\\‘e
shoulder
a clockwise
abduction
contained
have
form
of
to
ask:
nature
its
conjunct
to
rotation
sense
movement
followed
by
movement.
So
arm
Look
at
also,
the
right
from
not
nature,
Fig.
was
been
his
point
shoulder
THE
necessary
path.
for
The
the
diadochal
rotation.
as
from
is lateral
by
forward
BONE
AND
a
on anti-
respectively.
is,
of view,
OF
is,
Expressed
is clockwise
arm
followed
JOURNAL
is
‘‘
understanding
1.
on anti-clockwise
the
of
forces
a clockwise
movement
of
of
an
been
kinds
anti-clockwise-that
diadochal
swing
has
possible
of the
theorem
which
we are now considering.
at
arrow
a diadochal
is clockwise
backward
part
case
have
new
for
is
again
of our
the
wit/i
it
that
would
of
but
particular
rotation
rotation
the
is needed
consider
rotation.
associated
diadochal
to
of all
parallelogram
‘ ‘
theorem
in the
conjunct
; the
which
theorem
account
surfaces,
is
of the
; the
sense
of the
articular
general
takes
them
the
of
necessary
be illustrated
a
This
upon
general
is
It can
in
1946b).
movement
the
like
as the
right
are
of
path
been
according
arm.
in
be called
types
\\‘hat
examine
generalisation:
the
will
most
surfaces.
been
the
only
(MacConaill
diverse
the
of
having
questions
the
Had
flexion
a two-leg
diadochal
The
is a clockwise
clockwise
E
along
kilids
paper.
then,
vould
this
begin
the
study.
to Prevent
of it.
S\\’-\\’E
it
To
along
that
the
of its
apart.
E;
back
body
SE ; or
its
these
path
path
sphere,
is clear
that
a portion
longitude
along
with
picture
case
rigid
a
movement
elsewhere
convex
First,
the
simple
conjunct
possible
working
))1rposes
from
S to
of
with
to
proved
and
clear
It
actually
so.
as
of
at the
of swing
not
amount
its
surface,
SE.
compared
be
well
to slide
shown
arcs
is
degrees
of this
arrow
meridian
direction
careful
diadochal
the
answers
and
the
surface
at the
movement
case
every
rotation
is
eastwards
made
again
successive.)
conjoined
‘hat
to slide
pathway
special
a
mechanically
is then
corresponding
of the
call
legs
diadoclios,
counter-force
SOfl1C
It
from
1)ath
a two-leg
experiment
made
of
repay
moved
tvo
the
shoulder
to the
surface
as
90
the
is a very
will
be
(Gr.
movement.
distal
\\‘to
direct
Such
rotation
it to
shown
are
It is then
(lisplacements
the
is
‘ ‘
which
upon
along
example
and
pole
WS)
sliding
movement
from
no rotation
if it were moved
successive
can
to a stand-
(or converse
possible
in considering
pole.
Look
the
This
‘ ‘
arrow
It is also
simple
show
This
south
‘ ‘
humerus
of all
movement.
(ES,
a clockwise
S.
from
arrow
either
of
northwards
of the
sum
south
ES.
slid
part
the
equator.
degrees
surface,
The
at
meridian
directly
moved
Its
a small
of
the
is brought
humerus
The
of generality
meridians
westwards
original
humerus
of the
any
of
loss
of a sphere.
it reaches
the
of the
of swing.
sphere
is no
of two
that
arc
‘‘
there
half
)ointing
it reaches
flexion
rotation
all know
displacement
it is J)laced
S\V
but
7 is a picture
(\\‘E)
passive
or medial
line-the
surface-the
sphere
MACCONAILL
effect.
a curved
curved
()f a true
equator
so that
lateral
analysed-We
moves
constitutes
fibres
previous
has
experiment
joint
a
capsular
also
A.
Thus,
the
subject’s
rotation
swing
JOINT
of
of the
SURGERY
THE
arm
is,
from
rotation
the
subject’s
Secondly,
what
Fig.
1.
whole
figure
angles.
In
In this
angles
less
is the
is equal
by the two
the
bony
plane
of
reader
between
is referred
to
In
the
right
and
paper
cited
cut
and
other,
sum
direct
“
of
the
for
stage
two,
justification
at
this
from
right
angles.
of conjunct
of the
thefirst
to
of
of
easily
angle
between
the
path.
The
diadochal
of the
formed
and last positions
the
the
rotation
triangle
approximation.
It
is
self-evident.
THE
The
studied
limbs.
Detailed
of
will
the
rotation
actions
industrial
physiology
consideration
of the
the
law
of
OF
has
a bearing
of individual
; 3) the
first
conjunct
CONJUNCT
upon
three
and
muscle
and
therapy
muscles
diagnosis
and
second
rotation
is
When
the
and
When
the
arm
hangs
lateral
is swung
movement
the
first
side
long
an
topics
must
clear.
In
is independent
and
of the
or
and
that
The
cerebro-cortical
limb,
limb.
and
The
more
general
particular
its
by
muscle
simple
rotators
lateral
that
“
of effort
of
conjunct
be
to test
and
returning
the
the
imposed
rotation
30 B,
G
“
NO.
the
the
general
the
shoulder
to
which
can
be
which
spasticity
would
1948
of this
Arthur
Lynch
muted,
carried
be
of
out
than
into
anatomy
same
the
have
which
is largely
of the
the
set
back
of spinal
teres
that
in
exceeding
that
at
once
is
of teres
of the
deltoid
in one
another
which
to
around
position
position
is capable
sub-cortically,
or
lateral
movement
part
minor
of
earth.
business
nerves
nerves
the
axis
second
seen
that
leads
be
mind
comes
of the
to the
We
of movement
humerus
is to
deep
plane
a certain
of
of adding
it
requires
whereas
the
differentiation
when
has
directed
cortical
carried
play
in
for
extra
between
adjunct
by
as that
carrying
of spasticity.
performs
which
it ! There
(Lynch
a completely
a
or
“active”
and
nervous
the
of
is none
1923)
subject,
synergic
relaxa-
mechanism
which
rotation.
conversely.
passive
diadochal
it started;
inability
and
diadochal
relaxed
The
by
out
of
consciousness
Furthermore,
musculature.
muscles,
from
relaxation
is no
attention
upon
out
deep
he
activity.
the
be
muscles
synergic
There
writer
passively
are
sign
requires
permitted.
relaxing
therefore,
of descriptive
2, MAY
flexed
rather
must,
that
limb
a
however
arm
backwards,
the
to the
by
is controlled
concept
‘‘
: the result
that
a rate
say
of antagonism.
in the
is inhibiting
from
muscles
VOL.
even
rotation
“rotator”
possible
not
accompaniment,
part
This
types
rotation
cortex
in
affair.
two
of
the
differs
at
lateral
rotation
in
of
of
the
words
of spinal
fact
of slack
swing
rotation,
sense
up
set
in the
contraction
taking
backward
lateral
tion
but
mechanism
rotation
by
different
lies
if conjunct
is the
whom
and
is realised
“
largely
active
The
is a cortical
which
in
and
statement
of synergy,
The
that
another
slack.”
contraction
types
picture
‘‘
of this
rotation
up
medial
of
by
proof
conjunct
taking
adjunct
move-
affections
deferred
is to
axis.
one
two
of
to
; 2) the
perpendicular
then
business
to
of interest
groups
example
‘ ‘
vertical
muscle.
the
matters
limb-that
normal
brought
about.
When
the arm hangs
by the side lateral
minor ; when it is in a horizontal
plane it is largely
the
the
be
The
upwards,
around
other
of the
axis
axis
and
a swing
produced.
axis
the
with
forwards
is actually
is thereby
a standard
by
rotation-coincides
limb
backward
of
ROTATION
serve.
medial
rotation
)
: I
in
significance
SIGNIFICANCE
of conjunct
surgeons
ments
joint
PRACTICAL
phenomenon
orthopaedic
“
solution
magnitude
is equal
first
the
by
between
magnitude
plane
conjunct
contained
angles
is three
is to say three
right
of the angles
path
“
the
understood
two
: the
the
case
precise
be
sum of its
90 degrees-that
was
the
above
each
the
this
The
it can
generalised
this
the
?
but
and
angles
practice,
and
ES
be
In
arm.
rotation
interest,
can
path
swing
“
conjunct
and
325
JOINTS
of the
triangle,
rotation
result
two
considered.
direct
“
the
WE,
This
AND
movement.
rotation
practical
S\V,
of the diadochal
“
point
the
lines
angles.
difference
legs
“
the
BONES
anti-clockwise
of
than
SWE
is a spherical
this case the conjunct
right
to the
an
amount
rather
figure,
two
OF
is, medial
is of theoretical
The
right
not
viewpoint,
is anti-clockwise-that
problem
of
MOVEMENTS
Now
Hence
movements
to
the
it may
maintain
326
M. A. MACCONAILL
Rehabilitation
exercises-The
phenomenon
of conjunct
rotation
of exercising
muscles
which
are too weak to raise the limb as they
diadochal
movement
demonstrates
that
the action
of flexors,
adductors
includes
passively,
of
the
widely
have
a rotator
in the
bed
joint
which
used
already,
component,
or convalescent
is moved.
and
a mechanically
There
all
this
follows
will
is no
that
rational
it
chair,
that
call
need
writer
rotations
forth
to
carried
contractions
enlarge
wishes
appears
to offer a means
should
normally
do. Since
extensors,
abductors,
and
upon
to
show
one
and
upon
the
out
of all the
actively
muscle
this
device
; it
is that
such
simple
or
fibres
is no
doubt
exercises
basis.
SUMMARY
1. Two successive
movements
at a joint,
diadochal
movement.
2. Diadochal
movements
impose
conjunct
This
may
3.
All
4.
Upon
be countered
muscles
the
by a rotation
of a given
basis
joint
of these
if
not
rotation
of opposite
are,
therefore,
principles
in
the
same
bone
plane,
which
has
constitute
been
moved.
sense.
rotators
diagnostic
in some
and
degree.
therapeutic
suggestions
are
made.
REFERENCES
FICK,
R.
(1910):
T.
JOHNSTON,
Handbuch
B.
(1937):
A.
(1923):
MACCONAILL,
M.
A.
MACCONAILL,
M.
A.
LYNCH,
der
Anatomie
British
Principles
(l946a):
(l946b):
Journal
of
und
Psychology,
Irish
Irish
Journal
Journal
Mechanik
of Surgery,
London;
of
Medical
of Medical
der
25,
Gelenke,
Bd.
2,
Jena.
G.
Fischer.
252.
G.
& Sons.
6, 190.
Bell
Science,
Science,
THE
6,
JOURNAL
223.
OF
BONE
AND
JOINT
SURGERY
a