Lecture Notes on Psoas & Adductors
by Robert Schleip
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Psoas as a medial rotator
"In thus inserting on the medial
side of the femur (the rotators insert more laterally), the psoas major can
function as a medial and internal rotator of the thigh, balancing external
rotators."
This statement from Ida Rolf on page 170 of
her book on Rolfing is in clear contrast to the majority of anatomy books,
which usually claim that the psoas is an external (or lateral) rotator of the
femur. Here’s a possible biomechanical explanation for Ida Rolf’s controversial
statement.
The
crucial point to understand is that the axis of femural rotation does not go
through the middle of the femur shaft but passes medial of it. So when the
lesser trochanter is pulled anteriorly this also moves the greater trochanter
forward (not backwards) since both of them are located lateral of the axis of
rotation (see Fig.1 and Fig.2). Of course this is all based on the standard
kinesiological assumption that the body is in the so-called anatomical position
and that all other hip movements besides rotation (e.g. hip flexion or
adduction) are artificially prevented. (If you want, you may imagine someone
hanging a slippery glass plate directly anterior and another one medial of the
femur to prevent any movement of the femur in those directions, and then see
how the femur adapts in response to a psoas contraction.)
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Fig.1: Psoas pulls lesser trochanter forward |
Fig. 2: If lesser trochanter is pulled forward
to rotate around the axis, then the greater trochanter will also be pulled
forward |
The
biomechanical reasoning then goes like this
- The axis of femural
rotation will be a straight line passing through the middle of the hip joint
and the middle of the knee joint (see Fig.2). This line will pass slightly
medial (!) of the lesser trochanter in the anatomical position. Which
means that both the lesser trochanter and the greater trochanter are
located lateral of the axis of femural rotation.
- If the pelvis is kept
fixed and the femur mobile (yet only for rotational movement), a
contraction of the psoas will tend to pull the lesser trochanter in the
direction of the eminentia iliopubica where its fibers make a significant
bend around the pelvic bone. In the so-called anatomical position this
eminentia is located anterior in relation to the lesser trochanter
(Fig.1). This means that a contraction of the psoas will tend to pull the
lesser trochanter forward.
- Since both the lesser
trochanter and the greater trochanter are located lateral in relation to
the axis of rotation, a forward movement of the lesser trochanter will
also move the greater trochanter forward in relation to the axis of
rotation.
- A forward movement of
the greater trochanter around the axis of rotation is an internal rotation
of the femur.
Of
course this rotational movement of the femur is a rather tiny and weak
movement. The primary movement vectors of the psoas in terms of hip
flexion/extension and adduction are definitely much stronger. So I don’t
believe that it is very helpful to think of the psoas of being a possible
direct mechanical cause for an internally rotated femur. Yet it seems quite
clear that the common claim of many authors that a short psoas could be a direct
mechanical cause for a chronic external femur rotation, is based on a faulty
understanding. Also several popular osteopathic techniques now appear to be at
least questionable in which the femur is rotated medially together with a
hipjoint extension in order to "pre-stretch the psoas."
Psoas as a hip joint
extensor
In
her chapter on the psoas Ida Rolf drove many of us readers crazy by claiming
that the contraction of the psoas could move the lumbar vertebrae backwards.
This seems to be in contrast to the usual textbook description of the psoas as
a hip joint flexor muscle (which would usually tend to tilt the pelvis
anteriorly and thereby move the lumbars forward into a lordosis).
Interestingly,
recent EMG measurements of the psoas have shown that in the human body a psoas
contraction is often used to hold the lumbars posteriorly (see Calais-Germain,
B., Anatomy for Movement, p.62; or Tortora and Anagnostakos, Principles of
Anatomy and Physiology). How can that be?
Let's
look at the body mechanics first in a position where it is easier to see, in
the supine position with knees up, as for example for a ‘pelvic roll’ movement
education. If the long fibers of the psoas then contract, they will tend to
pull the lesser trochanter and T12 closer towards each other. Since the thorax
is resting heavily on the floor and prevents the upper psoas attachment to
move, it will be the lower attachment first that will move towards the other
one. Under water or without gravity this would probably mean raising the whole femur
off the ground in order to bring the lesser trochanter closer to T12. Yet in
the gravity field the weight of the thigh and leg prevents quite a lot of
resistance against this adaptation.
Fig.3: Client lying on floor with knees up. Contraction of the long psoas
fibers can tilt the pelvis posteriorly.
Now
lets suppose that the pelvis is relatively mobile for rolling movements around its
transverse axis, i.e. to respond by rolling into a more anterior or posterior
pelvic tilt position. Of course this assumes that the lumbar spine is not stiff[1]
and the hip joints are not held tight by spurious muscular holding patterns.
We
then have the following mechanical conditions:
- the sacroiliac joint is
posterior in relation to the acetabulum
- the femur is fixated
(i.e. a moderate psoas contraction can not lift it off the ground)
- the lower thorax is
fixated (a moderate psoas contraction will not lift T12 off the ground)
- the hip joints and
lumbar joints are relatively mobile to allow the pelvis to roll on the
floor into a posterior tilt direction
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Fig. 4: Simplified profile view of standing
client. If femur and lumbo-dorsal junction are stabilized (against forward or
backward movements of them), a contraction of the long psoas fibers may tilt
the pelvis posterior, thereby bringing the two ends of the psoas closer
towards each other. |
In
other words: If the thorax, feet and sacrum are kept resting on the floor, and
the hip- and lumbar joints are kept relative mobile, then the pull of the lesser
trochanter towards T12 will tend to roll the pelvis into a posterior direction
so that the pubic symphysis and lesser trochanter move a bit closer towards the
lumbo-dorsal junction. Which means this kind of psoas contraction will result
in a hip joint extension.
Practical application:
The ‘Pelvic Roll’
In order to activate the
psoas, I often use the following movement exercise. In supine position with
knees up, the client is asked to slowly tilt her pelvis anteriorly and
posteriorly.
1. Her usual first attempt to do
so is by a visible contraction of the
rectus abdominis during the posterior tilt direction.
2. When asked to put her soft hand
on her belly and feel if she can find a smooth rolling movement which does NOT
go along with abdominal contraction, most of the clients will then be able to
learn to roll the pelvis by pushing/extending their feet slightly against the
ground.
3. Finally as a third step some
clients are able to further discover that they can roll the pelvis only
"from within" without abdominal contraction and also without slightly
increasing the pressure of their feet towards the ground. (According to the
mechanical analysis of this article, this third style is seen as an
antagonistically alternating action among psoas and iliacus: when the iliacus
shortens, the pelvis rolls into a more anterior tilt position; and when the
long fibers of the psoas shorten, the pelvis rolls into the opposite
direction).
Yet
quite likely those EMG measurements mentioned before were not done in lying on
the floor, but rather in the upright position. Let's look at the biomechanics
in this position. Again, a contraction of the long psoas fibers will tend to
move the lesser trochanter and T12 closer towards each other. In the gravity
field in standing the weight on top of the legs will prevent the femurs from
moving easily. Also if the pelvis is shifted anteriorly in relation to the
thorax (which is not uncommon in standing) the lumbo-dorsal junction area will
have some mechanical resistance against being pulled forward due to the weight
and resulting backwards vector of the thorax and upper body on top of it. Yet
if the hip- and lumbar joints are free for a sagital tilting adaptation of the
pelvis around its transverse axis, the pelvis might actually respond by a
posterior tilt movement in order to bring the two attachment points of the long
psoas fibers closer together.
Iliacus
and psoas as antagonists? Yes, I think they often are. This also matches with
the palpatory experience of several of us Rolfing instructors that in an
anteriorly tilted pelvis (or innominate bone in a pelvic torsion) it is often
the iliacus which is short and tight; whereas in a posteriorly tilted pelvis
(or innominate) it is more often the long psoas fibers [2].
Another level where this antagonism between psoas and iliacus makes sense is in
relation to their enervation. The long psoas fibers are innervated from a
relatively high level of the spinal cord via the ‘lumbar plexus’, together with
the quadratus lumborum. Whereas the iliacus is innervated by a leg nerve, the
femoral nerve, which it shares with the sartorius, tensor FL and rectus
femoris. So in terms of their functional groupings via the nervous system, it
seems that the iliacus is associated as a leg muscle which flexes the hip
joint, whereas the long psoas is organized as a trunk muscle which stabilizes
the lumbar spine.
Iliopsoas in relation to scoliosis and pelvic torsion
There
have been several speculations claiming that an unilateral short psoas might be
a frequent cause–or at least contributing factor--for a scoliosis. In terms of
side-bending one would then suspect the lumbar spine to sidebend towards the
side of the shorter psoas. In terms of rotation one would suspect the psoas
fibers attaching at the lateral sides of the vertebrae to rotate this side more
anteriorly, which would result in a general rotation of those vertebrae away
from the side of the short psoas. Yet according to the generally accepted
‘Freyette’s First Law’[3] the lumbar vertebrae tend to rotate as a
group in the opposite direction, i.e. with their vertebral bodies towards the
side of their convexity (in relation to the observer). This rotation is also
how just about all scioliotic spines appear in x-rays.
IF
a short iliopsoas would indeed function as a significant factor for the
sidebending of a lumbar scoliosis, this should be testable in the following
way: with the pelvis kept immobile a hip joint flexion on the side of the short
psoas would result in immediate decrease of the scoliosis, whereas bringing the
femur back to line would increase the scoliosis again. Definitely not what one
often sees in scoliotic people!
Further
proof against the ‘iliopsoas theory’ of scoliosis comes from the fact that
several surgical attempts to improve a severe scolosis by cutting the ‘short’
psoas have been reported to have never yielded to success.[4]
Interesting
detail: the right iliacus has usually a closer fascial connection with the
intestines (specifically the ileo-cecal junction) whereas the right psoas has
usually a closer fascial connection to the (descending) colon. This could mean
that the usually common right-anterior pelvic torsion pattern could be in some
cases an adaptation to visceral strain onto the musculo-sceletal system. Yet
since any pelvic torsion will influence the "vertical distance" (i.e.
difference in height) between the acetabulum and the sacroiliac joint, such a
‘viscerally triggered’ torsion pattern is only likely if in standing the sacral
base appears higher on the side of the more anteriorly rotated ilium[5].
Which in my experience is the case only in less than 30% of the pelvic torsion
people.
Adductors in action
The
latest edition of the book 'Muscles Alive - Their Functions Revealed by
Electromyography' by J.V.Basmajian & C.J. De Luca provides some
interesting insights about the adductors[6].
In
the first edition of this book it was still written that "a surprising
hiatus appears in our knowledge of the adductors. Forming an enormous mass on
the medial side of the upper thigh, they must have considerable importance. In
spite of this, their exact function is usually a matter of guess work."
Since
then lots of EMG studies (surface and needle) have been done by Basmajian,
V.Janda and other researchers. Here are some of their newer findings:
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Besides in adduction the adductors are active during
MEDIAL hip joint rotation (except for the long vertical fibers of the add.
magnus), thereby "settling a classic argument that usually leaned in the
other direction."
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Additionally they are activated in other movements:
- the long portion of the adductor magnus acts
like a hamstring muscle in hip extension
- the gracilis assists in knee flexion
- the pectineus often assists in hip flexion.
·
Important difference between children and adults: In hip
joint flexion almost all children engage the long adductors, whereas only few
of the adults do so too.
·
Same interesting difference with knee extension
against resistance: most children use their adductors, and most adults don't.
This feature I must admit has been a stimulating surprise for me. The authors
suggest that "this labile response of the adductors is related to
postural response" and "these muscles are facilitated through
reflexes of the gait pattern rather than being called upon as prime movers.")
My
preliminary conclusions for our Rolfing work:
1.
The adductor muscles are not just functional adductor muscles of the leg
(otherwise they would not be required to be built as large as they are). They
are also designed to assist in hip extension (adductor magnus), knee flexion
(gracilis) and hip flexion (pectineus). It does not make sense to try to
mechanically "separate the adductors from the hamstrings" or
from the quadriceps in terms of separating their myofascia. Anatomically the
adductor magnus for example is supposed to have a firm gluing with the vastus
medialis and a shared septum with the semimembranosus[7]
which I do not want to change.
2.
In order to help a chronically internally rotated femur to rotate more out, it
seems indeed useful to do some work on the adductors.
3.
Also for chronically extended hip joint structures--i.e. posterior pelvis
tilt--it makes sense to include some releasing work on the adductor magnus.
4.
Some new inspiration for the 'knee forward-knee back' active client movement
participation in our fourth hour side-lying Rolfing position while working on
the adductors: Based on the above described difference between children and
adults it makes sense to look for and to work for a 'knee forward'-movement
without much adductor participation--which Ida Rolf would have probably called
a "more mature" movement pattern. My work then focuses on a
"functional differentiation" of the adductors during hip flexion. Yet
for the hip extension movement such a functional differentiation is less clear
or convincing.
5.
I now also include KNEE extension movement in the fourth hour ("move your
lower leg forward while keeping your upper leg where it is"). E.g. when
doing this movement with my own "not so good leg" against resistance,
I can detect the above described children's feature of an accompanying adductor
contraction. Which could be a sign of a spurious or immature co-contraction. I
now get some of my clients to do this knee extension movement (against slight
resistance from one of my hands) while I work with my other hand on their
adductor tissues and help these fibers to stay long and easy.
Tests for chronic
shortness of iliopsoas and adductors
V.
Janda[8] has developed (or refined) the following
tests for chronic myofascial shortness. In the so-called ‘Thomas-Test’ the
client is lying with his trunk supine, sitbones just on the very edge of the
table, both of his knees and hip joints maximally flexed with knees towards the
chest (see Fig. 5). The client firmly holds both knees with his hands towards
the chest (in order to stabilize the pelvis) and the examiner also leans with
his waist firmly against the sole of the left foot of the client to support
that pelvic stabilization. The examiner then takes the right knee of the client
and slowly drops it in direction of the floor. If the knee drops back to about
180 degrees of hip joint extension[9]
this is considered ‘normal’[10].
If the knee does not drop to that level, some hip joint flexor muscles with
their related myofascia are too short.
Which
one it is, can be determined by what happens at the end of that range of
movement. Like a "Sherlock Holmes in the myofascial net" the
practitioner can then make clear inferences from his observations.
- For example if the knee
joint then extends (by extending the lower leg significantly forward), the
rectus femoris is the "sinner."
- If the thigh abducts in
this position, it might be the tensor FL [11].
- If neither adaptation
happens, then the iliospsoas is short.
- If the femur rotates
externally, then it is the sartorius[12].
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Fig. 5: The
Thomas-Test position allows detailed analysis if a hip flexor shortness
exists, and if so which of the following tissues are primarily short: iliopsoas,
rectus femoris, tensor FL, or sartorius. |
Practical Application
Working with an anterior pelvic
tilt
If the client has a chronically
anterior pelvic tilt in standing, this can have several mechanical reasons.
1. First of all it can just be a
habitual postural collapse pattern which is NOT caused by any chronic
myofascial shortness. This option will show up easily when the client lies
supine on a flat firm surface and her hipjoints then extend all the way (i.e. to
180 degrees) with little or no lumbar lordosis.
2. Second option is that the
anterior tilt is caused by a chronic shortness of the lumbar erectors which
hold the lumbar spine in a lordotic pattern. This usually shows in the form of
a lumbar lordosis in this same test position which does NOT decrease
significantly when the knees of the clients are moderately elevated (by the
examiner, not the client)[13].
3. Third option is that the anterior
tilt is caused by a hip flexor shortness. This will show by a decrease of the
lordosis when the knees are passively elevated. Additionally it shows up in the
‘Thomas Test’ (see Fig. 5) in the inability of the femur to drop to a 180
degrees hip joint extension position. The same test then can be used to
determine which one of the hip flexors is the primary restriction: iliopsoas,
rectus femoris, tensor FL, or sartorius.
Depending on the proper diagnosis,
different working strategies will be appropriate:
-
In the first option the client needs postural and movement education
(including sometimes tonifying tissue work).
-
In the other options the identified shortened tissues need to be
lengthened (by the Rolfer and/or the client).
Unfortunately
there is no generally accepted test to distinguish between iliacus and psoas
shortness. I developed one which helps me only sometimes: in the side-lying
position with both hip- and knee joints flexed, I slowly lift the leg on the
ceiling side of the client and move it backwards several times into hip
extension. With my other hand I palpate with the thumb the middle of the sacrum
plus simultaneously with the third fingertip the spinous process of L3 (or
possibly higher). When at the end of the hip extension movement the pelvis
tilts anteriorly, I try to palpate if the lumbars move exactly simultaneously
with the sacrum or if they move slightly after the pelvic tilt[14].
To
test the adductors the client lies supine with their right body side close to
the edge of the table. The examiner abducts the client’s right leg with
extended knee as far as easily possible (see Fig. 6). 40 degrees of hip joint
adduction is considered ‘normal’[15].
At the end of the range of motion in this direction one can then bend that knee
joint 90 degrees (i.e. dropping the lower leg down while holding the knee) and
see if this allows a significantly larger range of hip abduction. If this is
the case, then it is the gracilis which is the most short. If not, one suspects
the other (1-joint-) adductors.
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Fig.6: Normal range
of abduction is 40 degrees. If the
adductors are chronically short this might be less. If the gracilis
is the first restriction, then dropping that lower leg down (i.e. knee
flexion) will yield a few more degrees of leg abduction than without. |
"The greatest
of all pleasures is the pleasure of learning"
- Aristotle
Copyright 1998, R.Schleip
First published in ROLF LINES, November 1998
For a very valuable response to this article, please
read M.Morrison: Further Thoughts on Femur Hip
Rotation and the Hip Flexors Psoas and Iliacus