The Psoas Psubstitutes, Part 4

By Thomas Myers

Illustrations by Andrew Mannie

Originally published in Massage Bodywork magazine, August/September 2001.
Copyright 2003. Associated Bodywork and Massage Professionals. All rights reserved.

This is the last of four columns on the psoas and its functions. In this issue we turn our attention to the neighbors of the psoas to see how they both duplicate and supplement its functions.

Locals and Expresses
First, let's begin by thinking a moment about single-joint muscles and their multi-joint counterparts -- a concept I have named "locals" and "expresses." If we think of the muscles as the motivating "trains" linked together by the fascial "tracks" (see "Anatomy Trains," Massage Bodywork, April/May 2000), then some trains are multi-joint "expresses," while the "locals" only cross a single joint.

The concept of expresses and local was introduced to Massage and Bodywork readers several years ago when we looked at the idea of the fourth hamstring. Here we see the biceps femoris on one side, with the underlying middle part of adductor magnus linking to the short head of the biceps shown on the other side.
In the human body, these expresses and locals often display a specific set of relationships. The hamstrings, for example, are expresses, in that they cross both the hip and the knee and act on both joints. Lift the hamstrings, however, and you will see two single-joint muscles which recapitulate the hamstrings' actions on each of the joints: the middle portion of the adductor magnus comes from the ischial ramus about halfway down the linea aspera, and acts to extend the hip like the hamstrings; and the short head of the biceps femoris which takes off from the same place on the linea aspera, continuing down below the knee to the fibular head, flexing the knee like the hamstring (Fig.1). We described this "fourth hamstring" in this magazine several years ago (Massage Bodywork, Fall 1998).

A similar example can be seen in the arm with the biceps brachii. The biceps itself comes from the scapula and runs down the superficial inside aspect of the arm to attach into the radius. It thus crosses three joints: the gleno-humeral joint at the shoulder, the ulno-humeral joint at the elbow and radio-ulnar joint in the lower arm (Fig. 2). The biceps is thus active in diagonal flexion and adduction of the shoulder, flexion of the elbow and supination of the lower arm. Look under the biceps and see the coracobrachialis crossing only the shoulder, leading to the brachialis which only flexes the elbow, and finally the supinator which only supinates the radius on the ulna. Once again, we see the multi-joint express lying on the surface, with the single-joint locals, each of which duplicate on the functions of the express, lying deep to it.

In the arm we see a parallel structure - the biceps brachii on one side, and the two locals underneath it - coracobrachialis and brachialis - on the other.
This is a fairly consistent pattern across the body -- think of the erectors, where the most superficial expresses cover many segments of the spine, while the shorter muscles lie closer to the spine itself (Fig. 3). The very shortest are the deepest, lying right next to the spine and covering only one segment.

Though there are exceptions to this pattern in the lower arm and leg, where the deepest muscles reach out to the tip of the fingers and toes, we could find examples of this "superficial express-deep local" pattern all over the body. The principles say that the muscle on the surface covers several joints, and that smaller, one-joint muscles can be found underneath, singling out the individual functions of the express. A second principle, which makes our discussion more relevant to practice, is that, in my experience, postural patterns are held in the deeper single-joint locals, and not so much in the multi-joint expresses. Expresses coordinate motion and make acceleration of complex actions smooth and even. In other words, chronic flexion of the elbow is not usually held in the biceps on the surface, but more often in the underlying brachialis. Real myofascial shortness (as opposed to just chronic muscular tension) in the biceps would limit the movement in all three joints, and render the muscle incapable of coordinating the complex movements of the arm.

The spinal muscles show another complex of superficial expresses acting over many segments of the spine, with the ever-deeper and ever-shorter locals covering fewer and fewer segments, down to the deepest which only cover a single segment.
Since massage training often highlights the surface muscles, and neglects the details of the deeper underlying muscles, I find additional training is often necessary for massage therapists to be able to locate these deeper locals consistently and easily. For example, the postural pattern where elbows are held close to the body and the hands face thumb or palm forward could be thought of as a chronic shortness in the biceps muscle. But work on the biceps alone rarely resolves this pattern. Rather, it requires the therapist be able to identify and specifically treat the coracobrachialis. If your training taught you to make that distinction, you are ahead of most of your colleagues.

Likewise, when looking at a postural extension of the hip or posterior tilt, the therapist is often referred to the hamstrings, but seldom to the underlying middle part of adductor magnus. The adductor magnus can be chronically tight without disturbing the function of the hamstrings. The hamstrings, in turn, can be chronically short, but are seldom responsible for postural positioning of the pelvis because they also are required to work the knee.

"Wasn't this column supposed to be about the psoas?" Okay, let's look at the psoas in the light of this "locals" and "expresses" idea. The psoas is clearly a multi-joint muscle. Starting from its distal attachment, it crosses the hip joint, the sacro-iliac joint and any number of lumbar spinal joints, depending on which part of the psoas you follow.

"But you just spent the last three columns talking about the postural effects of the psoas. Surely you are not going to backtrack now and say the psoas isn't a postural muscle? And besides, you said the expresses are on the surface and the locals lie deep to them, and there ain't nothing deep to the psoas."

Relax. Of course the psoas is a deep, postural muscle. But our point this time around is this: if we want to see real and lasting postural and movement change in our clients, we simply cannot ignore the locals, which duplicate the psoas' actions.

The Locals for the Psoas Express
The psoas express goes from the lesser trochanter to the 12th thoracic. To identify a set of locals, we will have to find muscles or fascial structures which cover similar territory in terms of start and finish, which are fascially or mechanically continuous, and which run more or less in a straight line, so pull from one to the other is plausible.

Here's the skinny -- the psoas has two sets of locals and they lie essentially beside, or around the psoas, not deep to it. This is cool, because that means we can reach them easily -- well, not that easily, but at least we don't have to go underneath the psoas to find them.

In the arm we see a parallel structure - the biceps brachii on one side, and the two locals underneath it - coracobrachialis and brachialis - on the other.

The Iliacus--QL Connection
If we start from the lesser trochanter end, the identity of our first local is not hard to guess because the psoas shares a tendinous insertion with the iliacus. If we follow the iliacus north to its proximal attachment, we see it go over the pectineal ridge of the pelvis, lateral to the psoas, and attach all along the inside surface of the iliac fossa, and especially right along the inner edge of the iliac crest (Fig. 4).

Now, what else attaches along that inner ridge of the hip bone? The tranversus abdominis shares an attachment with iliacus, but the direction of the fibers of tranversus is 90 degrees from iliacus, so it would not qualify as a set of locals because of the radical change of direction of the pull from muscle to the other. There is another muscle which attaches to the inside of the iliac crest, and this one keeps going in the same direction as the iliacus fibers -- the quadratus lumborum (QL).

A lot of people are surprised when they realize how deep the QL is, both literally and in terms of fascial planes. The QL, if you dissect this area of the body, is in fact continuous fascially with the inner pelvis and the iliacus. The fiber direction is largely the same. The QL starts from the iliac crest, where the iliacus ends, and goes up to the 12th rib and lumbar transverse processes, which is not exactly where the fibers of the psoas end, but very nearly. So these two muscles together form a "mini-psoas" or "quasi-psoas" divided into two sections: one that crosses the hip only and assists the hip flexion function of the psoas, and another which spans the lumbar spine and assists the spinal function of the psoas, especially lateral flexion. So the basic idea is this: if you are looking at a body and see it is pulled short from lower back to lesser trochanter, you might want to look not only at the psoas itself, but also at the iliacus-QL complex just lateral to it.

A cross-section through the lumbars shows how deep the quadratus lumborum is, and how difficult it would be to affect from the back.

Palpating the Iliacus and Quadratus Lumborum
A lot of folks announce they are going to work on the QL, and then proceed to put their fingers on the backside of the body between the iliac crest and the 12th rib, and attempt to open the tissues back there by getting their fingers well into the space under the 12th rib. I ought to know; I was taught it that way and did it myself for years. A look at Fig. 5 will show us how unlikely we are to affect the QL from back there, due to the large number of fascial and muscular layers between the back surface and the QL. The latissimus and the lumbodorsal fascia, the many layers of the erectors and their associated fascia, and even the fascia of the transversus and the rest of the abdominals come between my searching fingers and the QL. Approaching the body from this point of access, we are likely to affect the erectors, and may succeed in doing some nice work to lengthen the lower back through opening these tissues, but we are unlikely to have done much for the QL.

The QL fascia sweeps out and down from the 12th rib, and can be felt on the inner edge of the iliac crest at or just behind the body's midline.
The QL can be reached with certainty with the client in a side-lying position. Standing below the client's hip and facing the head, hook your fingers around the inside edge of the iliac crest, at or just forward of the midline. Now follow this inside edge backward. Somewhere at or just posterior to the body's lateral midline, you will find an edge that is carrying your fingers up toward the outer edge of the 12th rib. This is the outer edge of the QL fascia. Please note you must stay on the inner edge of the iliac crest to feel this. If you are on the top or the outside edge, your fingers will follow the curve of the top of the hip bone right back to the PSIS (posterior superior iliac spine), that big lump of bone near your sacrum with the dimples on top. The QL fascia can feel like a fabric layer in some well-stretched-out people, but in many of us couch potatoes or weekend warriors, it can be surprising how much this outer edge of the QL fascia feels like bone. The other surprise for students when they are directed to this structure for the first time, is how far lateral the QL fascia goes -- almost to the body's coronal midline. The anatomy texts most often show the QL muscle as going straight up and down between the 12th rib and the iliac crest (as shown in Fig. 3), but the fascial reality is the fascia connected with the muscle spreads, down and out from the 12th rib to the lateral iliac crest (Fig. 5B). Working the myofascia up from this outer edge, and from the tiny Petit's triangle between the leading edge of the latissimus and the trailing edge of the external oblique, will yield more certain results on the QL itself. This tiny muscle is very central, having effects on:

- breathing, through the QL's connection to the 12th rib and the diaphragm;
- the lumbar spine and walking, because of the way the fibers span and affect the lumbar transverse processes;
- and the kidneys, since these organs lie just in front of the QL and have some reflex connections with these muscles.

The iliacus can be more easily found, but is harder to work in its entirety. Again, curling your fingers around the iliac crest, you can feel the iliacus lining the inside of the ilium. It is easiest to feel near the ASIS (anterior superior iliac spine), but can be traced back with care (avoiding the coecum on the right and the sigmoid colon on the left) toward the anterior part of the sacroiliac joint at the posterior edge of the inner ilium. Having the client flex the hip will excite the iliacus into action, and having the client extend the hip will stretch it out from under your fingers. The client resting with the knees up (hips flexed, either side-lying or supine) will give you the easiest access to the farther reaches of the iliacus.

These two muscles together can form a fascial continuity from the lesser trochanter to the 12th rib and first lumbar. Most of the actions we ascribed to the psoas in previous articles could be applied to this set of locals, and sometimes we should turn to these smaller muscles when work on the psoas does not seem to be having the desired results. Chronic postural flexion of the hip, especially, is too often ascribed exclusively to the psoas, when in fact the iliacus, being a single-joint muscle of the hip, is the more likely culprit. Lateral flexion patterns of the lumbars, including unilateral high hips, should draw our attention to the QL.

The other psoas psubstitute includes the pectineus and the psoas minor.

The Pectineus -- Psoas Minor Connection
Unusually (but the psoas is nothing if not unusual), the psoas has two sets of locals: the one we have just described which runs lateral to and a bit behind the psoas, and the one we turn to now, which runs medial to and a bit in front of the psoas. This set of locals consists of the pectineus muscle connected up to the psoas minor muscle (Fig. 6). The pectineus runs from the lesser trochanter (and just below it -- the tendinous insertion is a band, not a point) widening up to the outside edge of the upper pubic bone. The psoas minor starts from the upper reaches of the psoas (meaning it has attachments to the 12th thoracic body) and runs down the front and inside of the psoas to attach onto the upper edge of the pubic bone. Again, there is a fascial continuity of these two structures. I say structures, because the psoas minor structure is only present as a muscle in about 50% of us, but is represented fascially in nearly everyone I touch. The psoas minor, when present as a muscle, pulls the pubic bone closer to the 12th thoracic, and is thus involved in lumbar flexion and posterior pelvic tilt. The psoas minor can be felt as a slick, tendinous strand on the anterior surface of the psoas, moving down onto the medial side of the psoas as you move lower on the muscle.

The pectineus pulls the pubic bone down into flexion, but also has an adduction component to its pull. This means the pectineus could either pull the femur into adduction, or, as in standing when the femur is fixed, it could pull the pubic bone toward the femur to create a pelvic rotation. Though its role in pelvic rotation has not been emphasized, we find it very involved, and treatment of this myofascia can be very effective in helping to untwist a pelvis where the pubic bone is not squarely set between the two femurs.

The area of the pectineus can be a touchy one, so it is best to start finding and working with it on yourself or someone you know well. Going into the groin or "leg pit" can be difficult for anyone. Touching the groin area with uncertainty or lack of confidence is bound to communicate through your hands, and will not bring good results. I often preface my work with a comment such as, "I need to work on the outside edge of your pubic bone now, so tell me if it gets too uncomfortable." Then, with the client supine and his knees up, I sit or stand next to the client with their knee under my armpit, such that the thigh is stabilized between my ribs and my arm. I put the flat of my palm against the inner thigh, with the fingers pointing into the groin. By having the client pull his knee against my arm, I locate the round, obvious tendon of the adductor longus, the one you can nearly always see when you sit cross-legged, and that you can certainly twang most easily on the inner thigh. I put my ring finger just on, or in front of, this tendon, and slide into the pocket right at the top inner part of the leg, just below the inguinal ligament. Sometimes I need to pull the skin a little bit one way or the other to have the necessary slack to get into the pocket.

Now my fingers are in the leg pit, just lateral to the pubic bone. I need to be sure I am not on anything that pulses, as this could be the femoral artery, which I do not wish to occlude. For this reason, this is an "endangerment site," but sensitive workers who avoid hurting their clients or pressing on things that press back rhythmically will be fine. Now I straighten (extend) my fingers and find the side of the pubic bone with the fingernail side of the tips. This is the attachment of the pectineus, but I prove it to myself by having the client lift their foot off the table, bringing their knee toward the opposite shoulder. This combination of flexion and adduction is sure to raise the pectineus, and, when I am on it, this action pops my fingers right out, assuring me I am in the right place. If you do not feel popped out by this strong muscle, have your client replace his foot, reposition your fingers next to the pubic bone just in front of the round adductor longus tendon, and try again. But you have to be fairly deep in the pocket of the femoral triangle to feel it.

Once you are sure you are situated correctly, gently pin the muscle and have the client slide his heel straight out toward the end of the table (if your primary concern is hip flexion) or lean the knee out past your body (if your primary concern is adduction or pelvic rotation). There is no question stretching this muscle can produce a lot of sensation in the client. It is a strong muscle, and sits in an ignored area with sexual and self-protective overtones, so proceed with caution and compassion. But don't ignore it, because if it is too short, it limits hip extension and abduction, as well as sometimes harboring stored emotional feelings.

While any lunge stretches groin tissues, turning the leg in emphasizes the iliacus-QL track, while turning the leg out will bring in the pectineus - psoas minor track.

Stretches for the Psoas Psubstitutes
If getting into either of these places is too difficult for you or the client, you can somewhat isolate these various tracks through lunging stretches, which are useful for assessment, or for client homework. If we take a simple, straightforward lunge, such as occurs in the yoga warrior poses or salute to the sun, we can see the hip flexors in the extended leg will be stretched. If, in the stretched-back leg, the heel is straight up, the psoas major will take the major part of the stretch. If the heel falls inward (and the weight comes onto the big toe side) then the pectineus-psoas minor track will also be included in the stretch. If the heel is allowed to fall to the outside (medial rotation of the femur, weight on the little toe side), then the stretch will include the iliacus-QL track. If you are steady on your feet in this position (or use a table to support yourself), you can move slowly from a medial rotation to a lateral rotation of the leg and feel the stretch move progressively along these three tracks. It is a matter of degree, of course -- all three tracks are stretched in hip extension -- and there will be some differences among individuals, but it's a good test for which track to work, and a good hip opener for those who have trouble getting their pelvis to sit squarely on their legs (Fig. 7).

This completes our tour of the psoas major and surrounding muscles. We hope you have enjoyed this speculative journey through its many functions and aspects. Next issue, we will turn our attention away from the hip and toward the shoulder, to consider the bodyworker's nemesis, the levator scapulae.

Thomas Myers, Certified Advanced Rolfer(R), LMT, NCTMB, studied directly with Drs. Ida Rolf and Moshe Feldenkrais, and has practiced integrative bodywork for more than 25 years in a variety of cultural and clinical settings. Myers directs Kinesis, Inc., which develops and runs training courses internationally for manual and movement therapists. He served as a founding member of the NCBTMB, and as chair of the Rolf Institute's Anatomy faculty. His articles have appeared in a number of magazines and journals, and a book is now available on his "Anatomy Trains" Myofascial Meridians approach. Myers retains a strong interest in perinatal and developmental issues around movement. His practice in Boston combines structural integration, physiological rhythmic sensitivity and movement. He lives, writes and sails on the coast of Maine.

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