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To understand how crunches, sit-ups, and leglifts operate mechanically, as well as to lay the groundwork for discussing standing, backward bending, forward bending, twisting, and sitting postures in later chapters, we must look at the pelvis and its relationships with the spine and thighs in detail.

trie hip bones and sacrum: the pelvic bowl

We'll first examine the pelvic bowl, which is formed from the combination of the two pelvic bones (the hip bones) and the sacrum—the lowest of the four main segments of the spine. The pelvic bones have two roles: one is to link the vertebral column with the thighs, legs, and feet; the other is to define (in combination with the sacrum) the base of the torso and provide a skeletal framework for the pelvic cavity and the organs of elimination and reproduction.

In the fetus each hip bone is made up of three segments: the ilium, the ischium, and the pubis. We often speak of them individually, but in adults they are fused together into one piece, with one hip bone on each side. To the rear, the iliac segments of the pelvic bones form right and left sacroiliac joints with the sacrum (fig. 3.2-4).

To understand the three-dimensional architecture of the pelvic bowl, there is no substitute for palpating its most prominent landmarks. You can start by feeling the crests of the ilium on each side at your waistline. Then locate the ischial tuberosities (the "sitting bones") behind and below: these are the protuberances upon which your weight rests when you sit on a bicycle seat or on the edge of a hard chair.

To continue your exploration, locate the two pubic bones in front, just above the genitals. They join one another at the pubic symphysis, a fibrocartilaginous joint which keeps the two sides of the pelvis locked together in front (figs. 1.12 and 3.2—4); their rami (ramus means "branch") connect with the ilia and ischia on each side (figs. 3.2-4). First trace the upper margin uf ea°h pubic bone laterally. What you are feeling are the superior pubic farm, bony projections that extend into the groin toward the ilium on each

••'Opsoas mUSCleS (hip flexors) act as Rvnernis»«; tn hrarn tho nolvic

Agonist Prime Mover Muscle

abdominal muscles act as agonists (prime movers)

Crunch exercise, safely lifting up an<l forward

Crunch exercise, safely lifting up an<l forward bent knees.

abdominal muscles act as agonists (prime movers)

side. An inch or so lateral to the pubic symphysis, these projections a overlain by the iliacus and psoas muscles passing out of the pelvis to thi combined insertion on the front of the femur. And beyond the softness f these muscles, the superior pubic rami connect with the ilia, which a again easily palpable.

Next locate the inferior pubic rami, which connect to the ischia (figs. 3.2-To find them, stand with your feet wide apart and lcx:ate the bones tli t extend from the base of the pubic region inferiorly, laterally, and posterioi They form a deep upside-down Y About halfway back each inferior pu c ramus merges into the next component of the hip bone, the ischium. 1 s hard to locate the lateral border of the inferior pubic ramus because ,e tendons of the adductor muscles (figs. 2.8, 3.8-9, and 8.13-14) are in the w y. And in the male it is also difficult to palpate the inside, or medial, bor r of the inferior pubic rami because the penis is rooted in the converg g arms of the V In the female the medial borders of these bones are m e accessible. In either case, following them posteriorly will finally lead yoi o the ischial tuberosities.

Returning to the ilium, which continues laterally from each supe ir pubic ramus, you will find a prominent bony point, the anterior super >r iliac spine, and just below this protuberance, the less obvious anterior in ft >r iliac spine (figs. 3.2-4). If your abdomen is not in the way, you will bee le aware of the right and left anterior superior iliac spines when you lie pi le on a hard surface. From these landmarks, trace the crests of the ilia later ly along the waistline. If you are slender and not heavily muscled, you in poke your thumb inside the iliac crest and feel the top half inch or so of le inside of the pelvic bowl from which the diacus muscle originates. Thei as you follow the crest of the ilium around to the back, you will come to aid mass of muscle, the erector spinae, below which the ilium articulates v h the sacrum.

the sacroiliac joints and the spine

The two pelvic bones connect with the rest of the torso through the saci en at the two sacroiliac joints (figs. 3.2-4), which are formed on each sid of the sacrum at the junction of two rough but matching surfaces (figs. 3.3 nd 6.2)—the lateral surface of the sacrum and the medial surface of the pe dc bone. Even though these are movable synovial joints whose mating surf es are bathed in synovial fluid, and even though their matching L-sh; "d groove-and-rail architecture permits some movement in children - nd healthy young adults, heavy bands of deep fasciae and well defined sacroi ac and iliolumbar ligaments (fig. 3-4> bind the joints together on the out de and restrain their movement in most people over the age of 25. Athli >c young women are notable exceptions; their sacroiliac joints are gener; ly

.$. abdomihopflvk F.xmasHs 14.1

more mobile than those for men in comparable condition. We'll explain the nature of the complex movements that are possible at the sacroiliac joint in chapter 6.

Anatomical differences account for some of the variations in .sacroiliac mobility between men and women, along with the female hormones estrogen, progesterone, and relaxin. The latter all become especially important in the last month of pregnancy for loosening up the sacroiliac joints, along with the pubic connections in front. All must yield to permit the passage of the baby through the birth canal.

Internally, the sacroiliac joints sometimes become ankylosed, which means they have formed a partial or complete bony union. Older men are particularly apt to develop this condition, and once it begins, their sacroiliac components can slip relative to one another only with considerable difficulty and unpleasantness. Such slippage usually happens as a result of a fall, but any impact that disturbs the partially locked relationship between the two sides of the joint will traumatize the opposing surfaces and probably cause extreme pain. Sacroiliac sprains (tears) of the binding ligaments are yet another problem: in this case they are a common cause of lower back pain.

Upper Border First Sacral

top border of sacrum (mates with intervertebral disk between L5 and the sacrum right hipbone pubic symphysis crest of the right ilium

|'9hl ischial tuberosity (sitting bone)--

antenor interior iliac spine left acetabulum (socket for hip joint)

left superior pubic ramus left inferior pubic ramus a single fused bone, the hipbone includes 3 parts: the ilium/ •he pubis and the ischium left hipbone left sacroiliac joint anterior superior iliac spine k'fiure 3.2. The female pelvis, with sacrum and (wo hipbones. The sacrum articulates in the rear with the ilia al the sacroiliac joints, and the two hipbones articulate with one another in front (by way of the right and left pubic bones) at "^e fibrocartilagenous pubic symphysis. Also see fig. 1.12 (Sappey).

144 ANATOM) OF HATHA YOGA

Because the sacroiliac joints in adults bind the pelvic bones so firmly the sacrum, every tilt, rotation, and postural shift of the pelvis as a win affects the vertebral column, and with the vertebral column, the enl body. If you rotate the top of the pelvis posteriorly (which is by definitioi posterior pelvic tilt, or colloquially, a pelvic "tuck"), the top of the sacr is carried to the rear, and this causes the lumbar curvature to flatten a lose its lordosis (forward arch), or in the extreme to become rouin spinous process of C2

Articular Surface Ilium

articular surfé (sacral) of the sacroiliac join!

articular surface (ilial) the sacroiliac joint ischial tuberosity crest of the ilium anterior superior iliac spine anterior inferior iliac spine superior pubic ramus attachment site foi pubic symphysis inferior pubic ramus

Pubis Articular Surface

Figure 3.3. The vertebral column (far right) is viewed from its right side, and thus reveals the sacral articular surface of the right sacroiliac joint. The right hip bone (below and to the left) is disarticulated from the sacrum and flipped horizontally, thus revealing its inside surface and the ilial fare of the right sacroiliac joint (Sappey).

anterior superior iliac spine anterior inferior iliac spine superior pubic ramus attachment site foi pubic symphysis inferior pubic ramus spinous process of C2

crest of the ilium articular surfé (sacral) of the sacroiliac join!

articular surface (ilial) the sacroiliac joint ischial tuberosity

.i. ABIXMIIKOItl I IC EXIlKCIShS 14$

posteriorly. On the Other hand, pulling the top of the pelvis forward, which ¡s defined as an anterior pelvic tilt, increases the depth of the lumbar lordosis. And if you stand on one foot the tipped pelvis wUI create side-to-side deviations of the spine.

iliolumbar ligaments anterior superior iliac spine anterior inferior iliac spine superior pubic ramus

Iliac Pubic

left iliac crest acetabulum (hip socket)

inferior pubic ramus

, . . ischial tuberosity pubic symphysis '

left iliac crest inferior pubic ramus

, . . ischial tuberosity pubic symphysis '

transverse process, L4 vertebral body, L5

iliolumbar ligaments anterior superior iliac spine anterior inferior iliac spine superior pubic ramus left sacroiliac joint and sacroiliac ligaments from the front acetabulum (hip socket)

left ilium iliolumbar ligament from behind

Iliolumbar Ligament

right sacroiliac joint and ligaments shared border of anal and urogenital triangles sacrum tip of coccyx (tailbone)

left ischium left ischial tuberosity left ilium iliolumbar ligament from behind right sacroiliac joint and ligaments anterior superior iliac spine anterior inferior iliac spine tefl acetabulum (hip socket)

left ischium left ischial tuberosity shared border of anal and urogenital triangles sacrum tip of coccyx (tailbone)

'gure 3.4. Pelvic restraining ligaments from the front (above) and from the S|de and behind (below). The borders of the diamond-shaped anatomical Perineum are shown below, and include the anal triangle behind (dotted 'lr|e), and the urogenital triangle in front (dashed line), with a shared border (solid line) connecting the two ischial tuberosities (Sappey).

ANAmm or hatha jog.-i the hip joints and their prime movebs

Most people understand the hip joints intuitively so long as they are deal ing with a simple imperative such as "bend forward from the hips," understanding that a simple "hip replacement" involves replacing the hea of the femur with a steel ball that will lit into the hip socket, Questionc beyond that, most people will fall silent; they have no notion of what mak< up the socket or how movements take place. But now we have begun develop a distinct image of the pelvic bowl. We have seen how the two pch bones are united in front at the pubic symphysis and how the pelvic boiv articulate with the sacrum behind, and we have palpated several boi landmarks on each side. We only need a few more details to complete t> picture.

The acetabulum (socket) for each hip joint is located at the lateral a; 1 inferior aspects of the pelvic bowl (figs. 3.2 and 3.4-5). You can't feel t e acetabulum, but you can feel the bony protuberance just below the jo t that sometimes bumps into things—the greater trochanter of the fen r (figs. 3.5-6). If you stand up and locate this landmark near where y< r hands fall alongside your thighs, you will notice that it moves around s you swing your thigh back and forth.

neck of femur head of femur (ball) ilium

Figure 3.5. Right femur (on the left) as viewed from (he front, and right hip bone (on the right) as viewed from the side. The head of the femur fits snugly into the acetabulum, forming a ball-and-socket joint (Sappey).

neck of femur head of femur (ball) ilium

Head Femur Articulates With Hip

Figure 3.5. Right femur (on the left) as viewed from (he front, and right hip bone (on the right) as viewed from the side. The head of the femur fits snugly into the acetabulum, forming a ball-and-socket joint (Sappey).

ischial tuberosity inferior pubic ran is ischial tuberosity inferior pubic ran is iliac crest ilium rectus lemons tendon iliofemoral ligament anterior superior iliac spine anterior inferior iliac spine

Ilium Anterior Superior Iliac Spine

superior pubic ramus site of attachment of fibrocartilagenous pubic symphysis ilial surface of sacroiliac joint

'RUre 3.6. Right hip bone, femur, and joint capsule, with the iliofemoral and Pubofemoral ligaments visible in front, and the ischiofemoral ligament hidden "^bind. These three ligaments in combination become taut during hip extension, a"d loose during hip flexion (for example, when the knee is lifted); (from Sappey).

femur ischial tuberosity inffnor pubic pubofemoral ligament superior pubic ramus

'RUre 3.6. Right hip bone, femur, and joint capsule, with the iliofemoral and Pubofemoral ligaments visible in front, and the ischiofemoral ligament hidden "^bind. These three ligaments in combination become taut during hip extension, a"d loose during hip flexion (for example, when the knee is lifted); (from Sappey).

rectus lemons tendon gluteus minimus muscle, and attachment sile on greater trochanter

The pelvic bowl is the foundation for all movements of the thighs at the hip joints, including flexion, extension, abduction, adduction, and rotation. To flex the thigh in a leglift (figs. 3.15-17) you contract the psoas and iliacus muscles (figs. 2.8, 3.7, and 8.13), which, as we have seen, run from the pelvis to the upper part of the femur in the case of the iliacus, and from the lumbar spine to the femur in the case of the psoas. For activities such as lifting each knee (as in running in place), or for stepping forward (as in walking), the origins of these muscles are on the torso and their insertions are on the thighs, but for sit-ups and crunches (fig. 3.1), the origins and insertions are reversed the thighs are fixed and the entire body is pulled up and forward.

To extend the thigh actively in a posture such as the locust (figs. 5.15-19) you tighten thegluteus maximus muscle (figs. 3.8, and 8.9-10), which takes origin from the posterior surface of the ilium and which has two insertions, iliofemoral ligament site of attachment of fibrocartilagenous pubic symphysis femur ischial tuberosity inffnor pubic pubofemoral ligament anterior superior iliac spine anterior inferior iliac spine ilial surface of sacroiliac joint iliac crest ilium t.|H ANATOMY OF HATHA 1 CX.A

one on the femur (fig. 3.10b), and the other in a tough band of connectiv« tissue—the iliotibial tract—that runs all the way down past the knee to th< leg (figs. 3.8-y and 8.12). You can feel the activity of the gluteus maximum become pronounced if you stand up and pull the thigh to the rear whil< pressing against the gluteal region with your hand. By contrast, man other postures such as the camel (figs. 5.34-35) hyperextend the hip join passively and this is resisted both by the psoas and iliacus muscles (figs 2.8, 3.7, and 8.13), and by the rectus femoris component of the quadricep femoris muscle (figs. 3.9, 3.11, and 8.8-9).

To abduct the thigh, which you do when you lift the foot straight out t the side, you tighten the gluteus medius and gluteus minimus musclt (figs. 3.8, 3.ioa-b, 8.9-10, and 8.12), which take origin from beneath lh gluteus maximus and insert on the greater trochanter. To adduct th thighs, which you do by pulling them together, you tighten the adduct< muscles, which take origin from the inferior pubic rami and insert belo on the femurs and tibias (figs. 2.8, 3.9, and 8.13-14).

if the muscles of the hips and thighs are strong and flexible, and if y( are comfortable extending the thighs fully in any standing, kneeling, 1 prone posture, you'll finally encounter resistance to extension in a de( 1 spiral of ligaments that surround the ball and socket hip joint—tl right and left crura of respiratory diaphragm (cut ends)

right quadratus lumborum psoas minor psoas major iliacus

Psoas Quadratus

greater trochant twelfth transvers1 abdomin left quadrat lumborum crest of" f left ilium cut end of If 1 psoas mus< s superior put ramus left femui twelfth thoracic vertebra (T12)

intervertebral disk between L5 and the sacrum joint insertion of right iliopsoas combination

Figure 3.7. Deep dissection of the pelvis and lower abdomen revealing the psoas and iliacus muscles and their conjoined insertions on the femurs. Their contraction lifts the thighs, thus bringing about hip flexion (Sappey).

greater trochant right and left crura of respiratory diaphragm (cut ends)

right quadratus lumborum psoas minor twelfth transvers1 abdomin psoas major left quadrat lumborum iliacus crest of" f left ilium intervertebral disk between L5 and the sacrum cut end of If 1 psoas mus< s superior put ramus joint insertion of right iliopsoas combination left femui twelfth thoracic vertebra (T12)

Figure 3.7. Deep dissection of the pelvis and lower abdomen revealing the psoas and iliacus muscles and their conjoined insertions on the femurs. Their contraction lifts the thighs, thus bringing about hip flexion (Sappey).

i ABOOMIXOPFJ. VIC EXERCISES 149

iliofemoral, ischiofemoral, and pubofemoral ligaments (fig. 3.(1). You won't feel this spiral unless you know it is there, but it will become increasingly taut as the thighs are extended. When that happens, the head of the femur is driven into the acetabulum of the pelvic bone in a near-perfect fit, and the thigh will extend no more. The spiral will unwind as the thighs aie flexed. If this spiral is removed and the hip joint opened up, the head of the femur and the acetabulum become visible (fig. 3.5).

fascia overtying gluteus medtus iliac crest ^ 3.

right gluteus maximus muscle intact right gluteus maximus: origin (cut)

Right Femur Origin And Insertion

hamstnng muscles:

semitendinosui biceps femoris semimembranosus ductor muscles (*)

right gluteus maximus: insertion on femur right gluteus maximus:

insertion in iliotibial tract fascia overlying right side of sacrum greater trochanter ductor muscles (*)

piriformis superior gemellus obturator intemus infenor gemellus "

quadratics femoris hamstnng muscles:

semitendinosui biceps femoris semimembranosus right gluteus maximus: origin (cut)

right gluteus maximus: insertion on femur fascia overlying right side of sacrum greater trochanter piriformis superior gemellus obturator intemus infenor gemellus "

quadratics femoris

Quadriceps Femoris Muscle
lateral head of quadriceps , femoris muscle 'I'Otibial tract

•gure 3.8. Right gluteal region and upper thigh from behind, with superficial "'^section on the left (a) and deeper dissection on the right (b). The partial cutaway of the gluteus maximus on the right (b) exposes deeper muscles of the "P. as well as a clear picture of the dual insertion of the gluteus maximus to he "•o tibia I tract and the femur (Sappey).

150 ANATOMY Of HATHA YOGA

the quadriceps femoris muscle

The quadriceps femoris is the largest muscle on the front of the thigh (fig 1.2, 3.9, and 8.8-9) arid the foremost anti-gravity muscle in the body Thr-of its four components, or "heads," take origin from the femur and act c the tibia by way of the patellar tendon. Its fourth head, the rectus femoi (figs. 3.9, 3.11, and 8.8-9), takes origin from the front of the pelvis (the anter: inferior iliac spine, figs. 3.2-6) and joins the other three components belt The quadriceps femoris is the muscle, more than any other, that stands y up from a squatting position. You can test its strength by standing in a bent-knee position for 30 seconds with your back fiat against a wall a then slowly rising. For those who are older and in a weakened conditu iliacus psoas muscle ihotibial tract

Quadriceps Femon

intervertebral disk between L5 and L4

adductors patellar tendon

- sartorius quadriceps femons tei patella

Figure 3.9. Right side of pelvis (deep dissection), right thigh, and right knee, a-viewed from the front (Sappey).

iliacus psoas muscle intervertebral disk between L5 and L4

adductors patellar tendon ihotibial tract

- sartorius quadriceps femoris muscle (three of the four heads, including the rectus femoris. are visible in this superficial dissection); the fourth head of this muscle is located deep to these three quadriceps femons tei patella

Figure 3.9. Right side of pelvis (deep dissection), right thigh, and right knee, a-viewed from the front (Sappey).

I AlMUMIhOPU. I K. BM M isrs 1st this is the muscle that gives them pause when they want to climb up or down stairs without holding onto a handrail. It is also Waterloo for inexperienced skiers who are trying to negot iate a bowl of deep powder for the first time: they ai"e firmly (even though wrongly) convinced that they have to keep their weight back and their ski tips visible to avoid toppling over into the snow. Although that can indeed happen—it's called a "face plant" or "header"— most novices overcompensate for the possibility and quickly pay for their error: quadriceps femoris muscles that are soon burning with pain.

the hamstring muscles

On the back sides of the thighs are the hamstring muscles, most of which have their origin on the ischial tuberosities. Like the quadriceps femoris muscles, the hamstrings insert below the knee joint, in this case both medially and laterally (figs. 3.10, 8.10, and 8.12). Tight hamstrings are the bane of runners—thousands of repetitive strides make these muscles shorter and shorter until they are barely long enough to permit full extension of the knees.

As two-joint muscles that pass lengthwise across two joints instead of one (from the ischial tuberosities of the pelvis all the way to the proximal ends of the tibias and fibulas), the hamstrings contribute both to extension of the thighs at the hip joints and to flexion of the legs at the knee joints. This architectural arrangement facilitates walking and running beautifully, but it creates a problem in hatha yoga. Since the hamstrings reside on the back sides of two joints—the knee and the hip—each of which is crucial in its own way for forward bending, these muscles are major obstacles to such movements. It's obvious that you could relieve tension on the hamstrings in forward bends by easing up either on hip flexion or knee extension, but releasing flexion of the hips would be contrary to the whole idea. What everyone does naturally is to flex their knees slightly, insuring that the hamstring muscles don't tug so insistently on the base of the pelvis as one attempts to bend forward. This was the principle involved in chapter 1 when we bent the knees before pulling the torso down against the thighs m the standing hamstrings-quadriceps thigh pull, and this is why we keep the knees bent in crunches. It is also why the knees should be bent if you insist on doing high-speed sit-ups. Otherwise the hamstring muscles tug on the ischial tuberosities from below and create too much tension in the lower back as you jerk yourself up and forward.

iiif_spine and abdominal wall

^he pelvic bowl is not merely the link between the thighs and the upper half of the body , it is also the foundation for the torso. Knowing this, if you 'ook at a skeleton, even with one glance, you will sense an immediate cause

152 Avrmin of HA tha >IM;A

gluteus minimus and its nerve branches adductor muscles and some of their nerve branches cutaneous nerves (to skin)

semimembranosus muscle and its nerve branches piriformis (origin from the underside of the sacrum) and its nerve branches

Muscles Near The Sacrum

short head of bice s femoris and two c its nerve branche:

long head ol bice > femoris and its nc e branches main trunk of so 'C nerve common peroneal nr je gluteus medius and its nerve branches piriformis (insertion c greater trochanter) and its nerve branct gluteus maximus (insertions on feme and iliotibial tract) and nerve branche nerve branches le the lateral head e the gastrocnemiu muscle adductor muscles and some of their nerve branches cutaneous nerves (to skin)

short head of bice s femoris and two c its nerve branche:

long head ol bice > femoris and its nc e branches semimembranosus muscle and its nerve branches main trunk of so 'C nerve semitendinosus muscle and its nerve branches common peroneal nr je f igure 3.10a. Nerves to muscles of tbe back of the hip and thigh originate fror spinal segments L4, L5, S1, and S2, and run down the back of the thigh on the extensor side of the hip joint. The large sciatic nerve and associated branches > the gluteus maximus emerge from just underneath the piriformis muscle (shov • intact in fig. 3.8b, in two parts connected by the dotted lines here in fig. 3.10a and removed except for its tendon of insertion in fig. 3.10b). Nerves to the glute s medius, gluteus minimus, and piriformis are shown above, and nerves to the hamstrings, gastrocnemius, and adductors are shown below. A superficial bran > of the common peroneal nerve swings around to an anterior, subcutaneous, ai I vulnerable position just below the knee (chapter 10); (from Sappey).

gluteus minimus and its nerve branches gluteus medius and its nerve branches piriformis (insertion c greater trochanter) and its nerve branct where emerges from under neath the piriformis gluteus maximus (insertions on feme and iliotibial tract) and nerve branche gluteus maximus and nerve branches that emerge from beneath the piriformis (dotted line)

medial head, — and lateral head of gastrocnemius muscle, and their nerve branches nerve branches le the lateral head e the gastrocnemiu muscle piriformis (origin from the underside of the sacrum) and its nerve branches t \BlHMmoPEL\lC k\atOSES 153

for alarm: there are many bones and much skeletal density in the pelvis and lots of ribs and vertebrae in the upper torso, but there are only five lumbar vertebrae connecting the two regions (figs. 4.3-4). This arrangement could not provide adequate support to the torso if it were acting alone. It needs the help of the soft tissues, especially sheets of muscle and fasciae. To that end the skeleton is supported by a "tube" containing the abdominal organs, a tube that is bounded in front and on the sides by the abdominal muscles, braced posteriorly by the spine and deep back muscles, capped by the respiratory diaphragm, and sealed off below by the pelvic diaphragm. The tube runs all the way from the sternum to the pubis in front but is quite short laterally.

Figure 3.10b. Right thigh, knee joint and hamstring muscles from the rear. The nip dissection, now revealing the gluteus minimus, is even deeper than the one shown on the right side of "g- .J.8. The piriformis and gluteus medius are now removed except for their tendons of insertion on ,tl(> greater trochanter, and "'e only remaining part of jhe gluteus maximus is its ■ernoral attachment.

piriformis muscle occupied (his space superior gemellus obturator internus inferior gemellus semitendinosus semimembranosus

Semitendinosus Attachment

iliac crest gluteus minimus piriformis tendon insertion of gluteus medius on greater trochanter quadratus femoris femoral attachment of gluteus maximus long head of biceps femoris (Short head, with its origin on the femur, is located deep to long head)

(from Sappey)

Figure 3.10b. Right thigh, knee joint and hamstring muscles from the rear. The nip dissection, now revealing the gluteus minimus, is even deeper than the one shown on the right side of "g- .J.8. The piriformis and gluteus medius are now removed except for their tendons of insertion on ,tl(> greater trochanter, and "'e only remaining part of jhe gluteus maximus is its ■ernoral attachment.

(from Sappey)

and media! heads of gastrocnemius muscle

---fascia overlying the soleus muscle piriformis muscle occupied (his space superior gemellus obturator internus inferior gemellus semitendinosus semimembranosus iliac crest gluteus minimus piriformis tendon insertion of gluteus medius on greater trochanter quadratus femoris femoral attachment of gluteus maximus long head of biceps femoris (Short head, with its origin on the femur, is located deep to long head)

154 ANATOMi Oh HATHA Y(X7A

We have four pairs of abdominal muscles (figs. 2.7, 2.9, 3.11—13» and 8.13). Three of these form layers that encircle the abdomen, and th fourth is a pair of longitudinal bands. The external abdominal oblique laye runs diagonally from above downward in the same direction as the extei nal intercostal muscles. If you place your hands in the pockets of a shoi jacket with your- fingers extended, the fingers will point in the direction 1 the external abdominal oblique muscle fibers. The internal abdomirn oblique layer is in the middle. Its fibers also run diagonally but in the opp. site direction, from laterally and below to up and medially in the sari direction as the internal intercostal muscles. The innermost third layer, tl transversus abdominis, runs horizontally around the abdominal wall fro left stemocleidomast i muscle right clavicle nght trapezius deltoid muscle serratus anterior (five segments showing)

Male Anatomy Deltoid

pectoi s major latissir s dors I

left extei al abdorni il oblique muscle (outerm t layer of abdomii muscles spermatic ci d suspers y ligamen; >1 penis fascia overlying rectus abdominis muscles testis right sartorius muscle right rectus femoris

Figure 3.11. Torso, with superficial muscles of the chest and neck, fascia covering th rectus abdominis muscles, and Ihe external abdominal oblique muscles (Sappey).

deltoid muscle serratus anterior (five segments showing)

fascia overlying rectus abdominis muscles left stemocleidomast i muscle pectoi s major latissir s dors I

left extei al abdorni il oblique muscle (outerm t layer of abdomii muscles spermatic ci d suspers y ligamen; >1 penis testis right sartorius muscle right rectus femoris right clavicle nght trapezius

Figure 3.11. Torso, with superficial muscles of the chest and neck, fascia covering th rectus abdominis muscles, and Ihe external abdominal oblique muscles (Sappey).

i AUfxiMiKom. \q<: txrjtctsts 15^

back to front. These three layers together act as a unit, helping to support the upper body and contributing to bending, twisting, and turning 111 a logical fashion. They are also necessary Tor coughing, sneezing, laughing, and various yoga breathing exercises.

The fourth pair of abdominal muscles, the rectus abdominis muscles (rectus means "straight"), run vertically on either side of the midline between the pubic bone and the sternum. As discussed earlier in this chapter, the rectus abdominis muscles are the prime movers (agonists) for flexion of the spine in crunches, while the hip flexors serve as synergists for bracing the pelvis and lumbal- region. The roles are then reversed for old style sit-ups, in which the hip flexors become the prime movers for jerking the torso up and forward at tbe hip joints, and the rectus abdominis muscles serve as synergists for bracing the spine.

the cavities and internal organs

Within the "tube" of the torso are the thoracic, abdominal, and pelvic cavities, as well as most of the internal organs. The heart, lungs, and esophagus lie within the thoracic cavity, which is bounded externally by the rib cage and inferiorly by the respiratory diaphragm (figs. 2.6-9). The serratus anterior (five segments)

external abdominal oblique (right)

fascia covering rectus abdominis

External Intercostals Location

serratus anterior internal intercostals external intercostals two of three tendinous inscriptions exposed rectus abdominis internal abdominal oblique (middle layer of abdominal muscles; left side)

spermatic cord in inguinal canal figure 3.12. External abdominal oblique and rectus abdominis fascia on •he torso's right side, and internal abdominal oblique and exposed rectus abdominis muscle on the torso's left side (Sappey).

serratus anterior internal intercostals serratus anterior (five segments)

external abdominal oblique (right)

external intercostals two of three tendinous inscriptions exposed rectus abdominis fascia covering rectus abdominis internal abdominal oblique (middle layer of abdominal muscles; left side)

spermatic cord in inguinal canal figure 3.12. External abdominal oblique and rectus abdominis fascia on •he torso's right side, and internal abdominal oblique and exposed rectus abdominis muscle on the torso's left side (Sappey).

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Responses

  • niklas
    How does the rectus abdominis muscle connect pubic bone?
    8 years ago
  • Amaranth
    Where is the external intercostal?
    8 years ago
  • Benjamin
    What is the intercostals location?
    8 years ago
  • tuuli
    Where are external intercostal located?
    8 years ago
  • Lelia
    Which has a rail sacrum or ilium?
    8 years ago
  • gisella mazzanti
    Which pair of muscles have their insertion on the iliotibial tract?
    8 years ago
  • DEREK
    Is the pubic rami the same as the iliac crest?
    8 years ago
  • jonna
    What is location of abdomen externally?
    8 years ago
  • Niklas
    What organs lie in front of L4, L5?
    7 years ago

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