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tremity and hip; and movement in the posterior direction for the knee, ankle and toes.

Extension is movement in the direction opposite flexion (i.e., in a posterior direction) for the head, neck, trunk, upper extremity and hip; and movements in an anterior direction for the knee, ankle and toes.

The difference occurs because the developmental pattern of the lower extremities differs from that of the upper extremities.

At an early stage, the limbs of the embryo are directed ventrally, the flexor surfaces medially, and the great toes and thumbs cranially. With further development, the limbs rotate 90° at their girdle articulation so that the thumbs turn laterally and the flexor surfaces of the upper extremities ventrally, while the great toes medially and the flexor surfaces of the lower extremities dorsally. As a result of this 90° rotation of the limbs in opposite directions, movement that approximates the hand and the anterior surface of the forearm is termed flexion, because it is performed by flexor muscles. Movement that approximates the foot and anterior surface of the leg is termed extension, because it is performed by extensor muscles. (For alternate terms regarding ankle motion, see p. 371).

Ankle

Extension Flexion

Shouldei

Elbow

Hip joint Wrist

Fingers Knee

Ankle

Extension Flexion

ABDUCTION AND ADDUCTION

A sagittal axis extends horizontally from front to back and lies in the sagittal plane. If the sagittal plane could bend at one of its axes, it would only bend sideways. It would not bend forward or backward or twist on itself.

The sagittal plane cannot bend, but the body can bend. In moving sideways from this plane (i.e., in a coro

nal direction), the movements of adduction and abduction and lateral flexion take place.

Abduction is movement away from, and adduction is movement toward, the midsagittal plane of the body for all parts of the extremities except the thumb, fingers, and toes (9). For the fingers, abduction and adduction are movements away from and toward the axial line that extends through the third digit. For the toes, the axial line extends through the second digit. For the thumb, see specific definitions on p. 258.

LATERAL FLEXION

Lateral flexion denotes lateral movements of the head, neck, and trunk. It occurs about a sagittal axis in a sideways (i.e., coronal) direction.

GLIDING

Gliding movements occur when joint surfaces are flat or only slightly curved and one joint surface slides across the other. The translational motion of the scapula on the thorax is an example of a gliding movement.

CIRCUMDUCTION

Circumduction is movement that successively combines flexion, abduction, extension, and adduction in which the part being moved describes a cone. The proximal end of the extremity forms the apex of the cone, serving as a pivot, and the distal end circumscribes a circle. Such movements are possible only in ball-and-socket, condy-loid and saddle types of joints.

MOVEMENTS IN THE TRANSVERSE PLANE

ROTATION

A longitudinal axis is vertical, extending in a cranial-caudal direction. Rotation refers to movement around a longitudinal axis, in a transverse plane, for all areas of the body except the scapula and clavicle.

In the extremities, rotation occurs about the anatomical axis except in the case of the femur, which rotates about a mechanical axis. (See p. 428.) In the extremities, the anterior surface of the extremity is used as a reference area. Rotation of the anterior surface toward the midsagittal plane of the body is medial rotation, and that away from the midsagittal plane is lateral rotation.

Because the head, neck, thorax and pelvis rotate about longitudinal axes in the midsagittal area, rotation cannot be named in reference to the midsagittal plane. Rotation of the head is described as rotation of the face toward the right or the left. Rotation of the thorax and pelvis generally are described as being clockwise or counterclockwise. With the transverse plane as a reference and 12 o'clock at midpoint anteriorly, clockwise rotation occurs when the left side of the thorax or pelvis is more forward than the right, and counterclockwise rotation occurs when the right side is more forward.

TILT

Tilt describes certain movements of the head, scapula, and pelvis. The head and pelvis may tilt in an anterior or posterior direction about a coronal axis. Anterior tilt of the head results in flexion (flattening) of the cervical spine, and posterior tilt results in extension. With the pelvis, however, the opposite occurs: Posterior tilt results in flexion (flattening) of the lumbar spine and anterior tilt results in extension.

The head and pelvis may tilt laterally, moving about a sagittal axis. Lateral tilt of the head may be referred to as lateral flexion of the neck. Lateral tilt of the pelvis is termed high on one side or low on the other.

Because the pelvis moves as a unit, tilts may be viewed as an anterior, posterior, or lateral tilting of the transverse plane, as seen in the accompanying illustration. There may be rotation of the pelvis along with the tilt, but this occurs more often with anterior and lateral tilt than with posterior tilt. (See p. 146 for movements of the neck, and p. 372 for movements of the pelvis.)

With the scapula in neutral position, there may be anterior tilt but not posterior tilt, except that return from anterior tilt may be referred to as such. (See movements of the scapula, p. 303.)

Shoulder / Medial

Lateral ^X-

Pronation Supination | Forearm is in supination)

Shoulder / Medial

Lateral ^X-

Pronation Supination | Forearm is in supination)

Longitudinal

Counterclockwise t rotation

Clockwise rotation

Medial rolatio pronation ol lorearrr eversion ot loot.

.supination ol lorearm; inversion ot foot

Eversion

Longitudinal

Counterclockwise t rotation

Clockwise rotation

Medial rolatio pronation ol lorearrr eversion ot loot.

.supination ol lorearm; inversion ot foot

Eversion

As is true in all testing, there must be a standard when evaluating postural alignment. The ideal, or standard, skeletal alignment involves a minimal amount of stress and strain and is conducive to maximal efficiency of the body. It is essential that the standard meet these requirements if the whole system of posture training that is built around it is to be sound. Basmajian states that "among mammals, man has the most economical of antigravity mechanisms once the upright posture is attained. The expenditure of muscular energy for what seems to be a most awkward position is actually extremely economical" (11).

In the standard position, the spine presents the normal curves, and the bones of the lower extremities are in ideal alignment for weight bearing. The "neutral" position of the pelvis is conducive to good alignment of the abdomen and trunk and of the extremities below. The chest and upper back are in a position that favors optimal function of the respiratory organs. The head is erect and in a well-balanced position that minimizes stress on the neck musculature. (See p. 65.)

The body contour in the illustrations of the standard posture shows the relationship of skeletal structures to surface outline in ideal alignment. Variations occur in body type and size, and the shape and proportions of the body are factors in weight distribution. Variations in contour are correlated, to some degree, with variations in skeletal alignment (12,13). This is essentially true regardless of body build. An experienced observer should be able to estimate the position of the skeletal structures by observing the contours of the body (14,15).

The intersection of the midsagittal and coronal planes of the body forms a line that is analogous to the gravity line (16). Around this line, the body is hypothetically in a position of equilibrium. Such a position implies a balanced distribution of weight and a stable position of each joint.

Various machines are available for use in evaluating postural alignment. The complicated machines, however, often introduce variables that are difficult to control. NASA noted that " [c] ommercially available movement/ posture evaluation systems require extensive data collection procedures, rigid camera calibrations, and referencing points" (17).

Fortunately, accurate postural examinations can be done with simple equipment at minimal cost.

When viewing a standing posture, a plumb line is used as a line of reference. Why a plumb line? Because it represents a standard. Based on nature's law of gravity, it is a tool in the science of mechanics. The simple device of a plumb line enables one to see the effects of the force of gravity. Invisible, imaginary lines and planes in space are the absolutes against which variable and relative positions as well as movements are measured.

In the study of body mechanics, plumb lines represent the vertical planes. With the anatomical position of the body as the basis, positions and movements are defined in relation to these planes. Body mechanics is the science that is concerned with the static and dynamic forces acting on the body. It is not an exact science, but to the extent that it is possible and meaningful, standards and precision must be incorporated in its study. The ideal alignment of the body is the standard.

The plumb line is a cord with a plumb bob attached to provide an absolutely vertical line. The point in line with which a plumb line is suspended must be a standard fixed point. Because the only fixed point in the standing posture is at the base, where the feet are in contact with the floor, the point of reference must be at the base. A movable point is not acceptable as a standard. The position of the head is not stationary; therefore, using the lobe of the ear as a point in line with which to suspend a plumb line is not appropriate.

The plumb line test is used to determine whether the points of reference of the individual being tested are in the same alignment as the corresponding points in the standard posture. The deviations of the various points of reference from the plumb line reveal the extent to which the subject's alignment is faulty.

For the purpose of testing, subjects step up to a suspended plumb line. In back view, they stand with the feet equidistant from the line. In side view, a point just in front of the lateral malleolus is in line with the plumb line.

Deviations from the plumb alignment are described as slight, moderate, or marked rather than in terms of inches or degrees. During routine examinations, it is not practical to try determining exactly how much each point of reference deviates from the plumb line.

The standing position may be regarded as a composite alignment of a subject from four views: front, back, right side and left side.

With ideal alignment as the standard, the positions of the head, neck, shoulder, upper back, lower back, pelvis and lower extremities are described and illustrated on the following pages.

Postural examination consists of three parts:

1. Examination of alignment in standing.

2. Tests for flexibility and muscle length.

3. Tests for muscle strength.

IDEAL PLUMB ALIGNMENT: SIDE VIEW

IDEAL PLUMB ALIGNMENT: BACK VIEW

Slightly anterior to axis of knee joint

Slightly posterior to apex of coronal suture

Through external auditory meatus

Through odontoid process of axis

Midway through the shoulder

Through bodies of lumbar vertebrae

Through sacral promontory

Slightly posterior to center of hip joint

Slightly anterior to axis of knee joint

Slightly anterior to lateral malleolus

Through calcaneocuboid joint

Slightly anterior to lateral malleolus

Through calcaneocuboid joint

In side view, the standard line oireference in the drawings and the plumb line in the photographs represent a projection of the gravity line in the coronal plane. This plane hypothetically divides the body into front and back sections of equal weight. These sections are not symmetrical, and no line of division is obvious on the basis of anatomical structures.

In back view, the standard line oi reference in the drawings and the plumb line in the photographs represent a projection of the gravity line in the midsagitlal plane. Beginning midway between the heels, it extends upward midway between the lower extremities, through the mid-line of the pelvis, spine, sternum, and skull. The right and left halves of the skeletal structures are essentially symmetrical, and by hypothesis, the two halves of the body exactly counterbalance (18).

HEAD AND NECK

The ideal alignment of the head and neck is one in which the head is in a well-balanced position that is maintained with minimal muscular effort. In side view, the line of reference coincides with the lobe of the ear, and the neck presents the normal anterior curve. In posterior view, the line of reference coincides with the midline of the head and with the cervical spinous processes. The head is not tilted upward or downward, and it is not tilted sideways or rotated. The chin is not retracted.

Good alignment of the upper back is essential for good alignment of the head and neck; faulty alignment of the upper back adversely affects the alignment of the head and neck. If the upper back slumps into a rounded position when sitting or standing, a compensatory change will occur in the position of the head and neck.

If the head position were to remain fixed with the neck held in its normal anterior curve as the upper back flexed into a position of round upper back, the head would be inclined forward and downward. However, "eyes seek eye level," and the head must be raised from that position by extending the cervical spine. In normal extension of the cervical spine, there is an approximation of the occiput, and the seventh cervical vertebra. As the head is raised to seek eye level, the distance between the occiput and the seventh cervical is reduced remarkably. Compared to the separation between the two points in ideal alignment, there may be as much as 2 or 3 inches of difference between the two positions.

The forward head position is one in which the neck extensors are in a shortened position and are strong, and the potential exists for the development of adaptive shortening in these muscles. The anterior vertebral neck flexors are in an elongated position and give evidence of weakness when tested for strength. (See radiographs on pp. 152 and 153.)

UPPER BACK

In ideal alignment, the thoracic spine curves slightly in a posterior direction. Just as the positions of the head and neck are affected by the position of the thoracic spine, so the thoracic spine is affected by the positions of the low back and pelvis. With the pelvis and lumbar spine in ideal alignment, the thoracic spine can assume the ideal position. If a normally flexible individual assumes a position of lordosis of the low back (i.e., increased anterior curve), the upper back tends to straighten, decreasing the normal posterior curve. On the other hand, habitual positions and repetitive activities may give rise to the development of a lordotic-kyphotic posture, in which one tends to compensate for the other. In a sway-back posture, the position of increased posterior curvature of the upper back compensates for a forward deviation of the pelvis.

SHOULDER

In ideal alignment of the shoulder, the side-view line of reference passes midway through the joint. However, the position of the arm and shoulder depends on the positions of the scapulae and upper back. In good alignment, the scapulae lie flat against the upper back, approximately between the second and seventh thoracic vertebrae, and approximately 4 inches apart (more or less depending on the size of the individual). Faulty positions of the scapulae adversely affect the position of the shoulder, and malalignment of the glenohumeral joint can predispose to injury and chronic pain.

A drawing of the standard posture appears on the facing page. Legends indicate the skeletal structures that coincide with the line of reference. For comparison, beside the drawing is a photograph showing a subject whose alignment closely approaches that of the standard posture.

In a side-view drawing of the standard posture, the artist has attempted to present a composite of male and female pelves, and to show an average in regard to shape, and length of sacrum and coccyx.

PELVIS AND LOW BACK

The relationship of the pelvis to the line of reference is determined to a great extent by the relationship of the pelvis to the hip joints. Because the side-view line of reference represents the plane passing slightly posterior to the axes of the hip joints, the pelvis will be intersected at the acetabula. However, these points of reference are not sufficient to establish the position of the pelvis, because the pelvis can tilt either anteriorly or posteriorly about the axes through the hip joints.

It is therefore necessary to define the neutral position of the pelvis in the standard posture. The neutral position used as the standard in this text is one in which the anterior-superior iliac spines are in the same horizontal plane and in which the anterior-superior iliac spines and the symphysis pubis are in the same vertical plane. From the standpoint of the action of muscles attached to the anterior iliac spines and the symphysis pubis, opposing groups of muscles have an equal mechanical advantage in a straight line of pull. The rectus abdominis, with its attachment on the pubis, extends upward to the stemum, and the rectus femoris, sartorius, and tensor fasciae latae, with their attachments on the anterior iliac spines, extend downward to the thigh.

Because of the structural variations of the pelvis, it is not practical to describe a neutral position on the basis of a specific anterior point and a specific posterior point being in the same horizontal plane. The anterior-superior iliac spines and the posterior-superior iliac spines are approximately in the same plane, however.

In neutral position of the pelvis, there is a normal anterior curve in the low back. In anterior tilt of the pelvis, there is a lordosis. In posterior tilt of the pelvis, there is a flat back.

Without minimizing the importance of proper foot positions that establish the base of support, it may be said that the position of the pelvis is the key to good or faulty postural alignment. The muscles that maintain good alignment of the pelvis, both anteroposteriorly and laterally, are of utmost importance in maintaining good overall alignment. Imbalance between muscles that oppose each other in the standing position changes the alignment of the pelvis, and adversely affects the posture of the body parts both above and below.

HIPS AND KNEES

The standard side-view line of reference through the lower extremities passes slightly posterior to the center of the hip joint and slightly anterior to the axis of the knee joint and represents a stable position of these joints.

If the center of the weight-bearing joint coincides with the line of gravity, there is an equal tendency for the joint to flex or to extend. However, this on-center position of the joint is not a stable one for weight bearing The slightest force exerted in either direction will cause it to move off center unless it is stabilized by constant muscular effort. If the body must call on muscular effort to maintain a stable position, energy is expended unnecessarily.

If the hip joint and knee joint moved freely in extension as well as in flexion, there would be no stability, and constant effort would be required to resist movement in both directions. A stable off-center position for a joint is dependent on limitation of joint motion in one direction. For the hip and knee, extension is limited. Ligamentous structures, strong muscles, and tendons are the restraining forces preventing hyperextension. Stability in the standing position is obtained by this normal limitation of joint motion.

Exercises or manipulations that tend to hyperextend the knee or hip joint or that excessively stretch muscles such as hamstrings should be scrutinized carefully. The normal restraining influence of the ligaments and muscles helps to maintain good postural alignment with a minimum of muscular effort. When muscles and ligaments fail to offer adequate support, the joints exceed their normal range, and posture becomes faulty with respect to the positions of knee and hip hyperextension. (See pp. 72, 81, and 84.)

ANKLE

The standard line of reference passes slightly anterior to the outer malleolus and approximately through the apex of the arch, designated laterally by the calcaneocuboid joint. Normally, dors i flex ion at the ankle with the knee extended is approximately 10°. This means that standing barefoot with feet in a position of slight out-toeing and with knees straight, the lower leg cannot sway forward on the foot more than about 10°. Forward deviation of the body (dorsiflexion at the ankle) is checked by the restraining tension of strong posterior muscles and ligaments. However, this element of restraint is materially altered with changes in heel height that place the ankle in varying degrees of plantar flexion, and it is appreciably altered if the knees are flexed.

FEET

In the standard posture, the position of the feet is one in which the heels are separated approximately 3 inches and the forepart of the feet are separated so that the angle of out-toeing is approximately 8° to 10° from the midline on each side, making a total of 20° or less.

This position of the feet refers only to the static and barefoot position. Both elevation of the heels and motion affect the position of the feet.

In establishing a standard position of the feet—and in determining where, if at all, out-toeing should occur—it is necessary to consider the foot in relation to the rest of the lower extremity. The out-toeing position cannot occur at the knee, because there is no rotation in extension.

In ideal alignment, the axis of the extended knee joint is in a frontal plane. With the knee joint in this plane, out-toeing cannot take place from the hip-joint level. There can be a position of out-toeing as a result of outward rotation of the hip. In this case, however, the entire extremity would be outwardly rotated, and the degree of out-toeing would be exaggerated.

This makes the question of whether there should be rotation of the foot into an out-toeing position dependent on the relationship of the foot to the ankle joint. The ankle joint permits flexion and extension only; it does not permit rotation. Unlike the knee joint, the ankle joint is not in a frontal plane. According to anatomists, it is in a slightly oblique plane. The line of obliquity is such that it extends from slightly anterior at the medial malleolus to slightly posterior at the lateral malleolus. The angle at which the axis of the ankle joint deviates from the frontal plane suggests that the foot is normally in a position of slight out-toeing in relation to the lower leg.

The foot is not a rigid structure. Movements of the subtalar and transverse tarsaljoints permit pronation and supination of the foot as well as abduction and adduction of the forefoot. The combination of pronation and forefoot abduction is seen as eversión of the foot and the combination of supination and forefoot adduction as inversion. Passive or active movements of the foot and ankle reveal that the foot tends to move outward as it moves upward and to move inward as it moves downward.

In the standing position, the foot is not fully dorsi-flexed on the leg, nor is it in full eversión. However, the person who stands with flexed knees and marked out-toeing of the feet will be in dorsiflexion and eversión—a position that results in stress and strain on the foot and leg.

It is not possible to determine the degree of eversión or inversion of the foot that corresponds with each degree of dorsal or plantar flexion. The two are not so correlated that an exact relationship exists, but it may be assumed that the movement from eversión in the dorsiflexed position to inversion in the plantar-flexed position is relatively uniform.

When influenced by shoes with heels, the standing position represents varying degrees of plantar flexion of the foot, dependent on the heel height. As heel height increases, the tendency toward a parallel position, or in-toeing, also increases.

The relationship of heel height to out-toeing or in-toeing of the foot is analogous to the position of the foot in standing, walking and running. When standing barefoot, a slight degree of out-toeing is natural. Standing with heels raised or walking fast, the feet tend to become parallel. As speed increases from walking to sprinting: The heels do not contact the ground, and the weight is borne on the anterior part of the foot entirely. There is then a tendency for the print of the forefoot to show in-toeing.

Ideal alignment. Kyphotic-lordotic posture

FOUR TYPES OF POSTURAL ALIGNMENT

The normal curves of the spine consist of a curve that is convex forward in the neck (cervical region), a curve that is convex backward in the upper back (thoracic region), and a curve that is convex forward in the low back (lumbar region). These may be described as slight extension of the neck, slight flexion of the upper back, and slight extension of the low back. When there is a normal curve in the low back, the pelvis is in a neutral position. In Figure A, the bony prominences at the front of the pelvis are in a neutral position, as indicated by the anterior-superior iliac spines and the symphysis pubis being in the same vertical plane.

Flat Back Posture
Flat-back posture Sway-back posture.

In a faulty postural position, the pelvis may be in an anterior, posterior, or lateral tilt. Any tilting of the pelvis involves simultaneous movements of the low back and hip joints. In anterior pelvic tilt, as shown in Figure B, the pelvis tilts forward, decreasing the angle between the pelvis and the thigh anteriorly, resulting in flexion of the hip joint; the low back arches forward, creating an increased forward curve (lordosis) in the low back. In posterior pelvic tilt, as shown in Figures C and D, the pelvis tilts backward, the hip joints extend, and the low back flattens. In lateral pelvic tilt, one hip is higher than the other, and the spine curves with convexity toward the low side. (For lateral pelvic tilt, see pp. 74, 75. 112.434. 435, and 439.)

IDEAL SEGMENTAL ALIGNMENT: SIDE VIEW

Head: Neutral position, not tilted forward or back. (Slightly forward in the photograph.)

Cervical Spine: Normal curve, slightly convex anteriorly.

Scapulae: As seen in the photograph, appear to be in good alignment, flat against the upper back.

Thoracic Spine: Normal curve, slightly convex posteriorly.

Lumbar Spine: Normal curve, slightly convex anteriorly.

Pelvis: Neutral position, anterior-superior spines in the same vertical plane as the symphysis pubis.

Hip Joints: Neutral position, neither flexed nor extended.

Knee Joints: Neutral position, neither flexed nor hyper-extended.

Ankle Joints: Neutral position, leg vertical and at a right angle to the sole of the foot.

Back Extensors

Hip Extensors

Back Extensors

Hip Extensors

Tensor fasciae latae

Rectus femoris

Abdominals

Rectus abdominis External oblique Hip Flexors

Psoas major lliacus

Tensor fasciae latae

Rectus femoris

In lateral view, the anterior and posterior muscles attached to the pelvis maintain it in ideal alignment. Anteriorly, the abdominal muscles pull upward, and the hip flexors pull downward. Posteriorly, the back muscles pull upward, and the hip extensors pull downward. Thus, the anterior abdominal and hip extensor muscles work together to tilt the pelvis posteriorly; the low back and hip flexor muscles work together to tilt the pelvis anteriorly.

KYPHOTIC-LORDOTIC POSTURE

Head: Forward.

Cervical Spine: Hyperextended. Scapulae: Abducted.

Thoracic Spine: Increased flexion (kyphosis).

Lumbar Spine: Hyperextended (lordosis).

Pelvis: Anterior tilt.

Hip Joints: Flexed.

Knee Joints: Slightly hyperextended.

Ankle Joints: Slight plantar flexion because ward inclination of the leg.

Elongated and Weak: Neck flexors, upper back erector spinae, external oblique. Hamstrings are slightly elongated but may or may not be weak.

The rectus abdominis is not necessarily elongated, because the depressed position of the chest offsets the effect of the anterior pelvic tilt.

Hip flexors are in a shortened position in both the sitting posture and the lordotic posture in standing (as illustrated above). However, low back muscles may or may not be tight. In sitting the back may flatten. This combination of circumstances has a bearing on the fact that low back muscle shortness is less prevalent than hip flexor short-of back- ness in this type of posture.

Short and Strong: Neck extensors and hip flexors. The low back is strong and may or may not develop shortness.

Drawing Figure

Head: Neutral position.

Cervical Spine: Normal curve (slightly anterior).

Thoracic Spine: Normal curve (slightly posterior)

Lumbar Spine: Hyperextended (lordosis).

Pelvis: Anterior tilt.

Knee Joints: Slightly hyperextended.

Ankle Joints: Slightly plantar flexed.

Elongated and Weak: Anterior abdominals. Hamstring muscles are somewhat elongated but may or may not be weak.

Short and Strong: Low back and hip flexor muscles.

Head: Forward.

Cervical Spine: Slightly extended.

Thoracic Spine: Upper part, increased flexion; lower part, straight.

Lumbar Spine: Flexed (straight).

Pelvis: Posterior tilt.

Hip Joints: Extended.

Knee Joints: Extended.

Ankle Joints: Slight plantar flexion.

Elongated and Weak: One-joint hip flexors.

Short and Strong: Hamstrings.

Frequently, abdominal muscles are strong. Although back muscles are slightly elongated when the normal anterior curve is eliminated, they are not weak. Sometimes, knees are slightly flexed rather than hypefe; tended along with the flat-back posture.

Figure A shows a marked anterior deviation of the body in relation to the plumb line, with the body weight being carried forward over the balls of the feet. It is seen most frequently among tall and slender individuals. Subjects who habitually stand this way may exhibit strain on the anterior part of the foot, with calluses under the ball of the foot and even under the great toe. Metatarsal arch supports may be indicated along with correction of the overall alignment. The ankle joint is in slight dorsiflex-ion because of the forward inclination of the leg and the slight flexion of the knee. Posterior muscles of the trunk and lower extremities tend to remain in a state of constant contraction, and the alignment must be corrected to achieve effective relaxation of these muscles.

Figure B shows a marked posterior deviation of the upper trunk and head. The knees and pelvis are displaced anteriorly to counterbalance the posterior thrust of the upper part of the body.

Figure C shows a counterclockwise rotation of the body from the ankles to the cervical region. The deviation of the body from the plumb line appears to be different when viewed from the right and left sides in subjects who have such rotation. The body would be anterior from the plumb line as seen from the right, but it would show fairly good alignment from the left. From both sides, however, the head would appear to be forward.

EXTERNAL OBLIQUE IN RELATION TO POSTURE

The muscles that hold the pelvis in posterior tilt during leg lowering are chiefly the rectus abdominis and external oblique. In many instances, abdominal strength is normal on the trunk-raising test, but the muscles grade very weak on the leg-lowering test. Because the rectus must be strong to perform the trunk curl, the inability to keep the low back flat during leg lowering cannot be attributed to that muscle. It is logical to attribute the lack of strength to the external oblique, not to the rectus. Furthermore, the postural deviations that exist in persons who show weakness on the leg-lowering test are associated with elongation of the external oblique.

Two types of posture exhibit this weakness: anterior tilt (lordotic posture) and anterior displacement of the pelvis with posterior displacement of the thorax (sway-back posture). The lateral fibers of the external oblique extend diagonally from the posterolateral rib cage to an-terolateral pelvis. By this line of pull, they are in a position to help maintain good alignment of the thorax in relation to the pelvis or to restore the alignment when there is displacement. (See photographs on facing page.)

The difference in grades between the trunk-raising test and the leg-lowering test is often very marked. Examination frequently reveals leg-lowering grades of only fair (5) to fair+ (6) in persons who can perform many curled trunk sit-ups. It becomes very clear in such situations that the trunk-raising exercise does not improve the ability to hold the low back flat during leg lowering. Indeed, it appears that repeated and persistent trunk-flexion exercises may contribute to continued weakness of the lateral fibers of the external oblique. (See p. 201.)

The type of postural deviation that occurs depends to a great extent on associated muscle weakness. In the anterior tilt, or lordotic posture, there is often hip flexor tightness along with the abdominal weakness; in the sway-back posture, there is hip flexor weakness, specifically of the iliopsoas.

The type of exercise indicated for strengthening the obliques depends on what other muscles are involved and what postural problems are associated with the weakness. The manner in which movements are combined in exercises determines whether they will be therapeutic for the individual. For example, alternate leg raising along with pelvic tilt exercises would be contraindicated in cases of hip flexor shortness but would be indicated in cases of hip flexor weakness.

To correct anterior pelvic tilt, posterior pelvic tilt exercises are indicated. The movement should be done by the external oblique, not by the rectus or by the hip extensors. The effort must be made to pull upward and inward with the abdominal muscles, making them very firm, particularly in the area of the lateral external oblique fibers. (See p. 215.)

To exercise the external oblique in cases of a sway-back posture, the same effort should be made to pull upward and inward with the lower abdominal muscles, but the pelvic tilt is not emphasized. This type of faulty posture already has a posterior pelvic tilt along with the hip flexor weakness. Contracting the lateral fibers of the external oblique in standing must be accompanied by straightening, not flexing, the upper back because these muscles act to shift the thorax forward and the pelvis back by the diagonal line of pull. Properly done, this movement brings the chest up and forward and restores the normal anterior curve in the low back. (See below.)

When properly done, the wall-sitting and the wallstanding exercises (p. 116) stress the use of the muscles of the lower abdomen and lateral fibers of the external oblique.

Expressions such as "make the lower abdomen cave in," or "hide the tummy under the chest." or in the vernacular of the military, "suck in your gut" are all used to encourage the subject to exert strong effort in the exercise.

Proper exercise of abdominal muscles should be a part of preventive medicine and physical fitness programs. Good strength in these muscles is essential to the maintenance of good posture, but one must avoid overdoing both the trunk curl and the pelvic tilt exercises. The normal anterior curve in the low back should not be obliterated in the standing posture.

LENGTH OF OBLIQUE ABDOMINAL MUSCLES IN RELATION TO POSTURE

Note the similarity between the lordotic and the sway- sway-back curve might be referred to as lordosis which back curves in the back. Without careful analysis of the it is not. differences in plumb alignment and pelvic tilt, the

Good Postural Alignment: Pelvis is in neutral position.

Dots representing the external oblique are 6 inches apart with the subject in good alignment.

Dots representing the internal oblique are 6 inches apart with the subject in good alignment.

Lordotic Posture: Pelvis is in anterior tilt.

Flat-Back Posture: Often, the external oblique is strong in this type of posture.

Sway-Back Posture: Pelvis is in posterior tilt.

Dots representing the internal oblique are 5 inches apart with the subject in sway-back posture.

Dots representing the external Dots representing the external oblique are 7 inches apart with the oblique are 7'/2 inches apart with subject in a lordotic posture. the subject in sway-back posture.

72

SWAY-BACK POSTURE SWAY-BACK POSTURE

Hyperlordose Der Halswirbels Ule

Head: Forward.

Cervical Spine: Slightly extended.

Thoracic Spine: Increased flexion (long kyphosis) with posterior displacement of the upper trunk.

Lumbar Spine: Flexion (flattening) of the lower lumbar area.

Pelvis: Posterior tilt.

Hip Joints: Hyperextended with anterior displacement of the pelvis.

Knee Joints: Hyperextended.

Ankle Joints: Neutral. Knee joint hyperextension usually results in plantar flexion of the ankle joint, but that does not occur here because of anterior deviation of the pelvis and thighs.

Elongated and Weak: One-hip joint flexors, external oblique, upper back extensors, neck flexors.

Short and Strong: Hamstrings, upper fibers of the internal oblique.

Strong but Not Short: Low back muscles.

The pelvis is in posterior tilt and sways forward in relation to the stationary feet, causing the hip joint to extend. The effect is equivalent to extending the leg backward with the pelvis stationary. With posterior pelvic tilt, the lumbar spine flattens. Hence, there is no lordosis, although the long curve in the thoracolumbar region (caused by the backward deviation of the upper trunk) is sometimes mistakenly referred to as a lordosis. (The term sway-back posture is an appropriate label and requires that the word sway-back not be used synonymously with lordosis.)

Head: Neutral position, neither tilted nor rotated. (Slightly tilted toward the right in the photograph.)

Cervical Spine: Straight in drawing. (Slight lateral flexion toward right in photograph.)

Shoulders: Level, not elevated or depressed.

Scapulae: Neutral position, medial borders essentially parallel and approximately 3 to 4 inches apart.

Thoracic and Lumbar Spines: Straight.

Pelvis: Level, both posterior superior iliac spines in the same transverse plane.

Hip Joints: Neutral position, not adducted or abducted.

Lower Extremities: Straight, not bowed or knock-kneed.

Feet: Parallel or slight out-toeing. Outer malleolus and outer margin of the sole of the foot in same vertical plane so that the foot is not pronated or supinated. (See p. 80.) Tendo calcaneus should be vertical when seen in posterior view.

Laterally, the following groups of muscles work to-er in stabilizing the trunk, pelvis and lower extrem-

Right lateral trunk flexors Right hip adductors Left hip abductors Right tibialis posterior Right flexor hallucis longus Right flexor digitorum longus Left peroneus longus and brevis

Left lateral trunk flexors

Left hip adductors

Right hip abductors

Left tibialis posterior

Left flexor hallucis longus

Left flexor digitorum longus

Right peroneus longus and brevis

Head: Erect, neither tilted nor rotated. (Slightly tilted and rotated right in the photograph.)

Cervical Spine: Straight.

Shoulder: Right low.

Scapulae: Adducted, right slightly depressed.

Thoracic and Lumbar Spines: Thoracolumbar curve convex toward the left.

Pelvis: Lateral tilt, high on the right.

Hip Joints: Right adducted and slightly medially rotated, left abducted.

Lower Extremities: Straight, neither bowed nor knock-kneed.

Feet: In the photograph, the right is slightly pronated, as seen in the alignment of the tendo calcaneus. The left is in a position of slight postural pronation by virtue of the deviation of the body toward the right.

Elongated and Weak: Left lateral trunk muscles, right hip abductors (especially posterior gluteus medius). left hip adductors, right peroneus longus and brevis, left tibialis posterior, left flexor hallucis longus, left flexor digitorum longus. The right tensor fasciae latae may or may not be weak.

Short and Strong: Right lateral trunk muscles, left hip abductors, right hip adductors, left peroneus longus and brevis, right tibialis posterior, right flexor hallucis longus. right flexor digitorum longus. The left tensor fasciae latae is usually strong, and there may be tightness in the iliotibial band.

The right leg is in "postural adduction," and the position of the hip gives the appearance of a longer right leg.

This posture is typical of right-handed individuals.

Head: Erect, neither tilted nor rotated.

Cervical spine: Straight.

Shoulder: Elevated and adducted.

Shoulders Joints: Medially rotated, as indicated by position of the hands facing posteriorly.

Scapulae: Adducted and elevated.

Thoracic and Lumbar Spines: Slight thoraco-lumbar curve convex toward the right.

Pelvis: Lateral tilt, higher on the left.

Hip Joints: Left adducted and slightly medially rotated, right abducted.

Lower Extremities: Straight, neither bowed nor knock-kneed.

Feet: Slightly pronated.

Elongated and Weak: Right lateral trunk muscles, left hip abductors (especially posterior gluteus medius), right hip adductors, right tibialis posterior, right flexor hallu-cis longus, right flexor digitorum longus, left peroneus longus and brevis.

Short and Strong: Left lateral trunk muscles, right hip abductors, left hip adductors, left tibialis posterior, left flexor hallucis longus, left flexor digitorum longus, right peroneus longus and brevis. With the elevation and adduction of the scapulae, the rhomboids are in a shortened position.

Right-handed

Left-handed

HANDEDNESS PATTERNS

Each of the above figures illustrates a typical pattern of posture as related to handedness. Figure A shows the pattern typical of right-handed individuals. The right shoulder is lower than the left, the pelvis is deviated slightly toward the right, and the right hip appears to be slightly higher than the left. Usually, there is a slight deviation of the spine toward the left, and the left foot is more pronated than the right. The right gluteus medius is usually weaker than the left.

Handedness patterns related to posture may begin at an early age. The slight deviation of the spine toward the side opposite the higher hip may appear as early as 8 or 10 years of age. There tends to be a compensatory ibV shoulder on the side of the higher hip. In most cases, the low shoulder is less significant than the high hip. Usually,, shoulder correction tends to follow correction of lateral pelvic tilt, but the reverse does not necessarily occur.

Figure B shows the opposite pattern, which is topical of left-handed individuals. Usually, however, the low shoulder is not quite as marked as in this subject. (See also page 95.)

FAULTY POSTURE: SIDE AND BACK VIEWS

Figure A is an example of posture that appears to be good in back view but is very faulty in side view.

The side-view posture shows marked segmental faults, but the anterior and posterior deviations compensate for each other so that the plumb alignment is quite good. The contour of the abdominal wall almost duplicates the curve of the low back.

Figure B shows a posture that is faulty in both side and back views. The back view shows a marked deviation of the body to the right of the plumb line, a high right hip and a low right shoulder. The side view shows that the plumb alignment is worse than the segmental alignment. The knees are posterior, and the pelvis, trunk and head are markedly anterior. Segmen-

tally, the anteroposterior curves of the spine are only slightly exaggerated. The knees, however, are quite hyperextended.

This type of posture may result from the effort to follow such misguided but common admonitions as "Throw your shoulders back" and "Stand with your weight over the balls of your feet."

The result in this subject is so much forward deviation of the trunk and head that the posture is most unstable and requires a good deal of muscular effort to maintain balance. The anterior part of the foot shows evidence of strain.

An individual with this type of fault might appear as someone with good posture when fully clothed.

Shoulders and Scapulae, Good Position: This subject illustrates a good position of the shoulders and scapulae.

The scapulae lie flat against the thorax, and no angle or border is unduly prominent. Their position is not distorted by unusual muscular development or misdirected efforts at postural correction.

Scapulae, Abducted and Slightly Elevated: In this subject, both scapulae are abducted, with the left one more than the right. Both are also slightly elevated. The abduction and elevation are accompanied by forward shoulders and round upper back. (For side view of this subject, see p. 153, Figure D.)

Shoulder Elevated, Scapulae Adducted: In this subject, both shoulders are elevated, with the right slightly higher than the left. The scapulae are adducted. The upper trapezius and other shoulder elevators are tight.

Shoulders Depressed, Scapulae Abducted: In this si ject, the shoulders slope downward sharply, accentuating their natural broadness. The marked abduction of the scapulae also contributes to this effect.

Exercises to strengthen the trapezius muscles, espe cially the upper part, are needed to correct the fault) posture of the shoulders.

Scapulae, Adducted and Elevated: In this subject, the scapulae are completely adducted and considerably elevated.

The position illustrated appears to be held by voluntary effort, but if this habit persists, the scapulae will not return to the normal position when the subject tries to relax.

This position is the inevitable end result of engaging in the military practice of "bracing" the shoulders back.

Scapulae, Abnormal Appearance: This subject shows abnormal development of some of the scapular muscles with a faulty position of the scapulae.

The teres major and rhomboids are clearly visible, and form a V at the inferior angle. The scapula is rotated so that the axillary border is more nearly horizontal than normal. The appearance suggests weakness of either the serratus anterior, or the trapezius, or both.

Abducted and Slightly Winged Scapulae: This subject shows a degree of scapular prominence that is rather frequent among children at this age (8 years). Slight prominence and slight abduction need not be a matter of concern at this age. This subject is borderline, however, and there is a difference in the level of the scapulae that might indicate additional muscle imbalance.

Abducted Scapulae and Forward Shoulders: This 9-year-old girl is rather mature for her age. The forward position of the shoulders is typical of that assumed by many young girls during the beginning development of the breasts. When such a postural habit persists, however, it may result in a fixed postural fault. (For side view of this subject, see p. 98, Figure B.)

fxim

Good Alignment of Feet and Pronation of Feet and Medial Ro-

Knees: The patellae face directly tation of Femurs: The distance be-forward, and the feet are neither tween the lateral malleolus and the pronated nor supinated. foot board indicates a moderate pronation of the feet, and the position of the patellae indicates a moderate degree of medial rotation of the femurs.

Pronation of Feet and Knock-

Knees: The feet are moderately pronated; there is slight knock-knee position but no medial or lateral rotation.

Feet Good, Knees Faulty: The alignment of the feet is very good, but medial rotation of the femurs is indicated by the position of the patellae. This fault is harder to correct by use of shoe corrections than one in which pronation accompanies the medial rotation.

Supinated Feet: The weight is borne on the outer borders of the feet, and the long arches are higher than normal. The perpendicular foot board touches the lateral malleolus but is not in contact with the outer border of the sole of the foot.

It appears as if an effort were being made to invert the feet, because the anterior tibial muscles are so prominent. However, the position shown is the natural posture of this subject's feet.

Lateral Rotation of the Legs: 1

eral rotation of the legs, as seen in this subject, is the result of lateral rotation at the hip joint.

This position is more typical of boys than of girls. It may or may ret have serious effects, although persistence of such a pattern in walking as well as in standing puts undue strain on the longitudinal arches.

GOOD AND FAULTY POSTURE OF KNEES AND LEGS

Knees, Good Alignment: In good alignment of the knees, as in this side view, the plumb line passes slightly anterior to the axis of the knee joint.

Knee Flexion, Moderate: Flexion of the knees is seen less frequently than hyperextension in cases of faulty posture. The flexed position requires constant muscular effort by the quadriceps. Knee flexion in standing may result from hip flexor tightness. When hip flexors are tight, there must be compensatory alignment faults of the knees, the low back, or both. Attempting to reduce a lordosis by flexing the knees in standing is not an appropriate solution when hip flexor stretching is needed.

Knee Hyperextension: With marked hyperextension of the knee, the ankle joint is in plantar flexion.

Good Alignment of Legs and Feet. Bowlegs: This figure shows a mild degree of structural bowlegs (genu varum).

Knock-Knees: This figure shows a moderate degree of structural knock-knees (genu valgum).

POSTURAL BOWLEGS AND KNOCK-KNEES

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