EVERY MAN IS A BUILDER OF A TEMPLE CALLED HIS BODY.
—HENRY DAVID THOREAU
IN THE FIRST yoga class I took with B. K. S. Iyengar, he began by teaching us Tadasana. What was so exciting was the way he integrated the philosophy of yoga into the actions of the body as he instructed the pose. He spoke of how the feet were bhakti yogis, that they served us by supporting us selflessly all day long. He pointed out that the thighs were karma yogis, that they did the work of walking. Throughout the class he clarified the actions and power of the lower extremities in asana by emphasizing the standing poses. Since then I have had a deeper appreciation for the importance of the legs and feet and their contribution to our practice.
The word pelvis means “basin,” which is exactly what the pelvis is: a basin to hold the organs of digestion, assimilation, elimination, and reproduction. The pelvis is also the pot out of which the spine grows; thus the position of the pelvis is critical for creating spinal alignment and health. The pelvis joins with the vertebral column through the sacrum and simultaneously balances itself through the hip joints, thus becoming a central fulcrum for the movements of asana.
To the yoga practitioner, in addition to its anatomical significance, the pelvis is the site of the lower three chakras, spiritual wheels that fuel the arising of kundalini energy and contribute to spiritual evolution. It is said that apana,the feminine energy living in all people regardless of gender, has its home in the pelvis. The pelvic floor is important too, as it is not only the site of important muscles that help to support the organs of the pelvis but also where aspirants focus techniques, such as Mulabandha (Root Lock), to control the movement of their energy.
The hip joint is important for so many asana that understanding its movements and limitations is key to teaching standing poses and forward bends, in particular.
8.1 ANTERIOR PELVIS, WITH THE ANTERIOR HIP LIGAMENTS
BONES
The pelvis is made up of three bones, the largest of which is the ilium, which forms the broad, flat bone of the pelvis. On the medial side of the ilia is a fossa known as the iliac fossa, where the iliacus muscle originates. The top of the ilia is called the iliac crest; it can be felt at the lower side waist (Figure 8.1).
The ability to locate the bony landmarks on the pelvis, both visually and tactilely, can make helping your student easier. Two important bony landmarks are found on the ilia. In the front of the body is the knobby anterior superior iliac crest. You can feel this at the lateral side of the low abdomen; sometimes when you lie on your belly it will poke the floor. The other landmark is the posterior superior iliac crest. It is found just over the sacroiliac joint on the posterior side of the body. Below each of these prominences is found a smaller crest, the anterior and the posterior inferior iliac crest, respectively (Figure 8.2).
The ischium makes up one-third of the pelvis and provides the two, rounded, firm ends of the pelvis on which we sit, the ischial tuberosities. Another important bony landmark on the ischium is the greater sciatic notch, made up in part of the ischium and the ilia. The greater sciatic notch is the passageway for the sciatic nerve to exit the pelvis. Distal to the greater sciatic notch is the lesser sciatic notch. This latter notch is converted into a true foramen by the sacrotuberous and sacrospinous ligaments; it allows for the passage of the tendon of the obturator internus muscle as well as nerves and blood vessels. The greater sciatic notch provides the opening for the passage of the sciatic nerve as well as for the piriformis muscle.
The third bone of the pelvis is the pubic bone, which also makes up one-third of the pelvis. The two rami (arms) of the pubis join with the ischium. On the anterior portion of the pubic bone is the pubic tubercle, a prominence that serves as the attachment for muscles. A rami of the pubic bone and a rami of the ischium join to create the obturator foramen. The obturator vessels and nerves exit the pelvis through this opening.
The front lower wall of the pelvis is created by the pubic symphysis, which is the union of the left and right anterior pubic rami. The pubic symphysis is composed of strong ligaments which hold the pubic rami together but which soften during pregnancy due to hormones and which separate slightly to allow for the passage of the baby from the pelvis.
8.2 POSTERIOR PELVIS, WITH THE POSTERIOR HIP LIGAMENTS
There are two ways to classify the opening in the central pelvis. The greater or false pelvis is the opening made up of the most superior aspects of the pelvis and is, of course, open on the anterior side. The lesser or true pelvis is the deeper cavity and is bounded by bony walls. The inlet of the lesser pelvis allows for the baby’s head to drop during the last part of pregnancy or during the early stages of labor. The pelvic outlet is the bony opening for the birth of the baby and is bounded in part by the pubic symphysis and the rami of the pubic bones, the sacrum, the coccyx, the inner ischium, and the lower inner ilium.
Gender Differences in the Pelvis. The male and female pelvis differ in a number of ways. These can be seen in the fetus as early as the fourth month. The differences are of course related to obstetric considerations. The female pelvis is more delicate, the ilia flare out more, and the acetabula and ischial tuberosities are farther apart. The superior inlet of the female pelvis is rounder, the cavity of the pelvis is shallower and wider, and the sacrum is wider and shorter. The coccyx is more movable. The acetabula are smaller and project more anteriorly, and the pubic symphysis is less deep. One interesting fact about the pelvis is that its size, unlike other bones, is not necessarily influenced by the size of the individual skeleton. In other words, even in tall people, the pelvis is not necessarily proportionally bigger.
Femur. The femur is the largest, longest, and strongest single bone in the body. It has a slight anterior curve that improves its ability to bear weight. The head of the femur presents a full rounded surface, which forms one half of the hip joint where it joins with the acetabulum (see the Joints section in this chapter).
The head of the femur tapers into a thin neck, which is the most vulnerable part of the upper femur. This is the most common site of fracture from falls in the elderly. Fractures happen to women more frequently due to the increased occurrence of osteoporosis at this site. In fact, some physical therapists believe that a spontaneous fracture of the femoral neck occurs first, resulting in a subsequent fall.
The neck of the femur has an angle of about 125 degrees to the shaft of the femur. The greater trochanter is a projection to be found at the site where the neck and the body of the femur join. It serves as an attachment point for muscles. It is easy to find the greater trochanter on your body. Stand in Tadasana, and feel the lateral uppermost femur. The greater trochanter will be that bony knob projecting laterally and slightly anteriorly.
The lesser trochanter can be found on the posterior side of the femur, at the base of the neck. It is a major site for the insertion of the psoas major muscle, which cannot practically be palpated from the outside.
The intertrochanteric line runs in an oblique angle between the greater and lesser trochanters and serves as an attachment point for soft tissue.
The long shaft, or body, of the femur curves not only anteriorly but medially, to bring the distal femur underneath the hip joint proper. In women, because the acetabula tend to be wider apart, there tends to be more of a medial curve than in men. On the posterior surface of the shaft is a raised line that runs most of the length of the bone and is called the linea aspera. It provides a place for the attachment of various muscles of the hip joint.
The distal end of the femur forms two major prominences called the medial and lateral condyles. These form the superior surfaces of the knee joint and are joined together on the anterior surface and separated more distinctly on the posterior surface. (The knee joint is discussed in detail in chapter 9). The medial condyle is the larger; it projects a proximal prominence called the medial epicondyle, which serves as a site for the attachment of connective tissue, the medial collateral ligament of the knee. The lateral epicondyle is not as large as the medial one; it is the site of connection of the fibular collateral ligament of the knee joint.
JOINTS
One of the key joints of the pelvis is the sacroiliac joint, which is discussed in detail in chapter 7. The other key joint of the pelvis is the hip joint.
The hip joint is formed by the union of the head of the femur with the acetabulum (Figure 8.3). The acetabulum is a deep, circular joint formed by the fusing of the ilium, the ischium, and the pubic bone in the following proportions: two-fifths from the ilium and the ischium and one-fifth from the pubic bone. The pelvis proper and the acetabulum are completely fused by the twenty-fifth year of life.
The femur sits in the acetabulum at an angle that may at first seem counterintuitive. Many yoga teachers think of the head and neck of the femur joining at the hip joint in the frontal plane, but this is not so. There is an angle to this relationship called femoral anteversion. In other words, the neck of the femur points anteriorly about 10 to 25 degrees, using the frontal plane as the point of reference.
Another way to understand anteversion is to visualize observing your student as if you were over the top of her head, looking down on her like she was a column. Because of the normal position of anteversion of the femoral neck, you would clearly be able to see that her femoral heads are anterior to her hip sockets, not parallel to them.
This means that the greater trochanter is anterior of the actual hip joint (acetabulum and femoral head) when it is in the neutral position. If the student stands with her greater trochanter in the frontal plane, parallel with her hip socket, she is actually standing in external rotation. However, if this anteversion is more than about 30 degrees, she will probably demonstrate a lack of external rotation.
The opposite of anteversion is femoral retroversion. This occurs when the angle of the femoral neck and head as it enters the acetabulum is less than 10 degrees. In this case, the student will demonstrate an extreme limitation of internal rotation.
The position of most stability in the hip joint is not this neutral or Tadasana position. Instead, the position of most stability for the hip joint is when the femur is in slight abduction, flexion, and external rotation. You can experience this position for yourself. Stand up and imagine that you are going to pick up a heavy load. As you imagine yourself doing this, you will no doubt separate your feet, turn your feet slightly out, and bend your knees and flex your hips. This is the position that professional weightlifters use when lifting. It is also the position of stability created in such poses as Utthita Trikonasana and Ardha Chandrasana.
If you do the opposite—that is, internally rotate the femurs instead—you will move the head of your femurs out of their sockets slightly (adduction), thus reducing the congruence of the head of the femur and the acetabulum. In fact, after total hip replacement surgery, the doctor recommends that the patient not ever cross her legs with the involved leg on top. If she does so, sitting in flexion, adduction, and internal rotation with the involved leg, she will be moving the head of the femur out of the socket and into the position of dislocation. Remember that the angle the neck of the femur has in neutral is a slightly forward position, so it is easier than you might think to move the head of the femur away from the acetabulum.
CONNECTIVE TISSUE
The ligaments of the hip joint are some of the strongest in the body. As a whole, they tend to limit abduction. The first is the iliofemoral, which lies on the anterior surface of the joint and runs from the anterior femur, around the neck of the femur, to insert on the intertrochanteric line. This ligament is also called the Y ligament of Bigelow. This ligament can limit back bending asana if the student externally rotates and abducts her femurs. In back bending the ligament is stretched. If the student internally rotates during back bends, the ligament will be less stretched.
The pubofemoral ligament runs from the superior ramus of the pubis to the distal iliofemoral ligament. Finally the ischiofemoral ligament originates from the ischium and blends with the hip joint capsule to insert. All three of these ligaments serve to reinforce and support the hip capsule.
8.3 HEAD OF THE FEMUR IN ACETABULUM, WITH THE LIGAMENTUM TERES
The ligamentum teres has another special function, in addition to helping to hold the joint together. The head of the femur is nourished by a single blood vessel that passes through the acetabulum inside a ligament called the ligamentum teres. Because this blood vessel and ligament are somewhat delicate, injury to them can disrupt the blood supply to the femoral head and cause avascular necrosis of the femoral head.
The acetabulum has a fibrocartilaginous rim that creates a lip around the joint. Not only does this deepen the joint, but it also protects the bony rim of the acetabulum. The center of the socket itself is bone, but there is a ring of cartilage around the outer periphery of the acetabulum. This cartilage, as does all cartilage, protects bony surfaces and facilitates easy movement; it may be as much as 9 mm thick. A distinct difference has been found in the formation and thickness of this cartilage when comparing physically inactive cultures and those in which people are very physically active from a young age.
Another significant connective structure that affects the hip joint is the fascia lata. This fascial sheath runs along the most lateral surface of the thigh; it arises from the pelvic bone, the thoracolumbar fascia, the inguinal ligament, and external abdominal fasciae. It travels down the outside of the thigh, connects with a variety of muscles, and finally inserts into multiple sites at the region of the distal femur.
8.4 ANTERIOR ILIAC AND THIGH MUSCLES
Finally, over the area of the greater trochanter, the aponeurosis of the gluteus maximus muscle blends into the fascia lata and is called the iliotibial band.
NERVES
The nerves of the pelvic region originate from the lumbar and sacral nerve plexuses. They are discussed in detail in chapter 6.
MUSCLES
The muscles of the pelvis and thigh are some of the strongest and most important in the body. They anchor the spine to the pelvis and the pelvis to the femur, help to form the floor of the pelvis, and allow us to stand and locomote. The charts that follow will help you to learn about these muscles. They are grouped by location and muscle action.
Anterior iliac and thigh muscles: hip flexors and knee extensors. The muscles of the anterior thigh are some of the biggest in the body (Figures 8.4 and 8.5). They work together to initiate the first part of locomotion and to maintain the extension of the knee joint during walking and standing. Also known in part as the “quads,” these muscles are strengthened by standing poses and are stretched by lunges and back bends
8.5 ANTERIOR ILIAC AND THIGH MUSCLES
8.6 GLUTEAL MUSCLES
Gluteal muscles: hip extensors, abductors and external rotators. The muscles of the gluteal region are at the core of movements of the hip joint (Figures 8.6 and 8.7). They contribute to the poses that require strength and are absolutely necessary for standing on one leg. The piriformis, both obturators, and the gemelli are together called the external rotators. They are strengthened by standing poses, back bends, and balancing poses.
8.7 GLUTEAL MUSCLES
Medial thigh muscles: adductors and internal rotators. These powerful muscles help to keep the femur from abducting too much during the swing phase of walking (Figures 8.8 and 8.9). In other words, as you are standing on your left leg and swing your right leg through to step on the right foot, the right adductors help to keep your right leg moving straight ahead instead of wandering off to the right as it swings through, thus creating a more efficient gait. The adductors are strengthened and stretched by standing poses and certain seated poses in which the thighs abduct. Examples include Prasarita Padottanasana, Upavistha Konasana, and Baddha Konasana.
8.8 MEDIAL THIGH MUSCLES
Posterior thigh muscles: hip extensors and knee flexors. Even beginning yoga students become highly aware of their hamstring muscles early in their practice, as they are generally taught to stretch them from the very first class (Figures 8.10 and 8.11). This muscle group is much smaller than the hip flexor-knee extensor group, but it usually receives more attention in yoga class. The hamstrings are strengthened during hip extension against gravity, such as in Urdhva Dhanurasana. They are stretched by hip flexion, especially when the knee is extended. All forward bends stretch the hamstring muscles when the knee is held straight and the hip joint flexed. One example is Paschimottanasana.
8.10 POSTERIOR THIGH MUSCLES
8.9 MEDIAL THIGH MUSCLES
8.11 POSTERIOR THIGH MUSCLES
Pelvic floor muscles. The pelvic diaphragm covers the lower opening at the base of the pelvis to support the abdominal organs and gives support to the pelvic organs (Figures 8.12 and 8.13). The pelvic floor has several openings, including openings for the anus, the urethra, and the vagina. These are the muscles used in Kegel exercises, asvini mudra, and mulabandha. The following muscles contribute to the pelvic floor: levator ani, coccygeus, deep transverse perineus, sphincter urethrae, ischiocavernosus, bulbospongiosus, superficial transverse perineus.
8.12 PELVIC FLOOR MUSCLES
8.13 PELVIC FLOOR MUSCLES
KINESIOLOGY
During the practice of Urdhva Dhanurasana, teachers sometimes notice that their students turn their feet and knees out instead of keeping them straight ahead. This occurs when the students are not using their adductor muscles. Here’s what is happening. In order to push up into hip extension into the pose against the downward pull of gravity, the gluteus maximus must be used. The gluteus maximus is a hip extensor and has a secondary action of external rotation as well. When the gluteus maximus contracts, it extends the hip joint and externally rotates it at the same time. In order to counteract this secondary component of the gluteus maximus, the external rotation component must be neutralized by internally rotating.
The adductors are the internal rotators. In order to press the knees toward each other in a straight line, you must activate your adductor muscles. This neutralizes the external rotation component of the gluteus maximus and makes it easier for the pelvis to rotate backward over the femoral heads in the back bend. This is what happens in asana class when a teacher asks you to place a lightweight foam block between your knees in Urdhva Dhanurasana. By pressing on the block, you activate the adductors and thus neutralize the external rotation component of the gluteus maximus.
EXPERIENTIAL ANATOMY
For Practicing
8.14 TADASANA
Applied Practice 1: Experiencing Tight External Rotators in Forward Bends
Prop: 1 nonskid mat
Take Care: If you have any problems with balance, try this near the wall.
ONE OF THE PERSISTENT difficulties yoga students encounter is a limitation of hip flexion because of tightness of the hamstring muscles. Some students find that even with diligent practice the ability to bend forward does not seem to improve very much. Part of the reason could be the tightness of the external rotators.
Here’s how it works. While most teachers rightly assume that the action of the external rotators is to externally rotate the femur, these muscles act in another way in daily life. The most common job of the external rotators is to stabilize the pelvis during the swing phase of walking. In other words, when you step out on your right foot, as you transfer your weight onto that foot, there is a period of time in which you are standing on one leg. As your right foot and leg take the weight of your body, the external rotators of the right hip contract to keep the pelvis level to the floor as you swing your left leg through to step on it.
Try it yourself. Stand in Tadasana on your nonskid mat (Figure 8.14). Step on your right foot, and place your fingers over your right rotators, just posterior to the right greater trochanter. As you feel your left leg lift and swing through, you will feel a strong contraction in the right rotators. Therefore every step you take is one in which the external rotators must contract. This strengthens and tightens the rotators, as do poses in which you stand on one leg or strongly externally rotate, as in many standing poses and back bends.
To understand directly how the rotators interfere with hip flexion, try this. Stand in Tadasana and turn your feet out, contracting the external rotators strongly and pressing your buttocks together. Now hold this position of your femurs and try to bend forward into Uttanasana. It will be very difficult, if not impossible. This is simulating the situation of tight external rotators.
Now internally rotate your femurs. This action is the opposite of external rotation and thus will stretch the external rotators. You will find that bending forward is much easier (Figure 8.15). This is because when stretched, the rotators no longer hold the pelvis back, preventing it from rotating over the femoral heads so that hip flexion can occur. Therefore, to improve your forward bends, stretch not only your hamstrings but also your external rotators.
8.15 UTTANASANA
8.16 EXTERNAL ROTATOR STRETCH, WITH BOLSTER
Applied Practice 2: Stretching the External Rotators
Props: 1 nonskid mat a bolster (or a blanket folded to 1” x 21” x 28” and rolled firmly from its short end)
Take Care: Skip this practice if it causes pain in your knee joint.
PLACE YOUR BOLSTER crosswise on the mat. Step across the bolster with your right leg, and sit in Eka Pada Rajakapotasana, with your right buttock and upper right thigh resting on the bolster (Figure 8.16).
Your back leg should be straight and internally rotated and your front tibia placed exactly parallel to the short edge of your mat. Pay special attention to this; most students bring the heel in too far instead of making the right tibia parallel to the mat at both the upper and lower tibia.
Make sure that you roll your weight toward the left, lifting your right buttock until it barely presses the bolster, while keeping your right femur firmly on the bolster. This should cause a strong stretch in the right external rotators, especially if you bend forward. Remember to keep breathing as you stretch and to repeat on the other side.
Why this works may be perplexing at first. The rule states that when you want to stretch a muscle, you need to do the opposite of what that muscle does when it contracts. Thus to stretch an external rotator, you need to internally rotate, moving in the opposite direction of the muscle’s action. So why are the external rotators stretched in a position of external rotation? This position stretches the external rotators because they are on the posterior surface of the body, and, when you bring the femur into flexion, you begin to stretch the structures on the posterior side.
For Teaching
8.17 TADASANA
Applied Teaching 1: Neutral Hip Position in Tadasana
Prop: 1 nonskid mat
Take Care: Make sure that your student’s feet are pointing forward and are not turning in or out.
HAVE YOUR STUDENT stand in Tadasana and first just observe his hip joints from the side and from the front (Figure 8.17). Look at the point where his thighs join his trunk on the anterior side of the body. There should be a small indentation there if the hip joints are in true neutral. Remember, this means that his trochanters are forward of the hip sockets. When he stands with his femurs slightly externally rotated, there will be less or no indentation there.
Now stand behind him, and, after asking permission to touch, place your hands on his greater trochanters. They should be facing slightly anteriorly, due to anteversion of the femoral head in the acetabulum. If they are not, suggest that he slightly internally rotate to bring them into a neutral position.
8.18 SUPTA PADANGUSTHASANA
Applied Teaching 2: Improving Hip Flexion for Supta Padangusthasana
Prop: 1 nonskid mat
Take Care: Do not lie on your back if you are more than four months pregnant. ASK YOUR STUDENT to lie down on her mat for Supta Padangusthasana (Figure 8.18). First observe as she raises her straight leg up to an angle of 90 degrees. Many students raise the leg with an action that appears as if they are lifting the whole femur at once. Watch this action several times. Now suggest that she lift her femur in a different way: have her imagine that the head of her femur is descending just as she begins the action, in order to allow the rest of the femur to lift. It is as if the femoral head rolls down, back, and out as she raises the thigh and leg up. This way of thinking about the action is more in harmony with what the head of the femur actually does in the movement. Instead, most students just pick up the whole lower extremity and lift it. This way of moving does not allow for the femoral head to move deep into the joint for a mechanically sound movement with increased congruence. This type of movement does not follow the concave- convex law for this joint.
8.19 PASCHIMOTTANASANA
Applied Teaching 3: Improving Forward Bends with Internal Rotation
Prop: 1 nonskid mat
Take Care: Make sure your student is moving from the hip joints to minimize strain to the lower back.
DURING SEATED forward bends, such as Paschimottanasana (Figure 8.19), suggest that the student that internally rotate. One way to do this is to move the inner thigh down firmly toward the floor. When he does this, he will keep the femur in a more neutral position as he bends forward, thus facilitating flexion.
LINKS
Asvini mudra is a seal that is practiced to direct energy in the body. Mudras are practiced to help to channel energy that is moving in one direction in the body to move in another way. Asvini refers to the anal sphincter of a horse as it contracts and releases during defecation; mudra means “seal.” During the practice of yoga poses, Asvini mudra is the contraction of the pelvic floor. This is what women do when they practice Kegel exercises to improve continence and sexual functioning. Asvini mudra also happens spontaneously during the practice of many asana—for example, Urdhva Dhanurasana—due to the strong action of the adductor muscles spilling over to include pelvic floor contraction.
Mula means “root”; Mulabandha is the strong contraction and elevation of the pelvic floor, especially using the pubococcygeus muscle. The difference between Asvini mudra and Mulabandha is twofold. Asvini mudra is a contraction of the pelvic floor to prevent the body’s subtle energy from moving down. Mulabandha is the lifting of the pelvic floor, not only to stop energy from moving down but to actively move it upward. The point of Mulabandha is to move the apana, or downward feminine energy of the pelvis, upward so it can be maintained in the kunda, or vessel of the trunk, and thus will be available for spiritual work.
Mulabandha is usually employed during advanced pranayama techniques, but some systems of yoga deliberately employ it during asana practice. Other systems of hatha yoga believe that this bandha occurs naturally during the practice of asana when alignment of the body is perfected.