Roja ramani vasamshettyMPT II

Because the force of gravity is constantly acting on the body, an ideal posture is one in which the body segments were aligned vertically and LOG passes through all joint axes. Normal body structure makes such an ideal posture impossible to achieve; but it is possible to attain a posture that is close to the ideal one.

•In normal optimal standing posture, the LOG falls close to but not through, most joint axes.

•Therefore in normal optimal standing posture the gravitational torques are small and can be balanced by counter torques generated by passive ligamentous tension, passive muscle tension and minimal amount of muscle activity.

•If faulty postures are habitual and assumed continually on daily basis, the body will not recognize these faulty postures as abnormal and over time, structural adaptation such as ligamentous and muscle shortening or lengthening will occur.

ANALYSIS OF POSTURE

The effect of external forces on body segments in the sagittal plane is determined by the location of LOG in relation to axis of motion of body segments.

When the LOG passes directly through a joint axis, no gravitational torque is created around that joint.

However, if LOG passes at a distance from the axis, a gravitational torque is created.

This torque will cause rotation of the superimposed body segments around that joint axis unless it is opposed by a counterbalancing internal torque.

The magnitude of gravitational moment of force increases as distance between LOG and joint axis increases.

•If the gravity line is located anteriorly to the joint axis, the torque will tend to cause anterior motion of the proximal segment of the body supported by that joint and vice versa.

•In a postural analysis, external gravitational torques producing sagittal plane motion of the proximal joint segments are referred to either flexion or extension moments.

•Skilled observational analysis of posture involves identification of location of body segments relative to LOG.

•A plumb line or a line with a weight on one end is used to represent LOG.

•More sophisticated analysis may be performed using radiography, photography, EMG, electrogoniometry, force plate or 3D computer analysis.

Sagittal plane: contd

Joints LOG Gravitational moment

Passive opposing force Active opposing force

Atlanto-occipital

AnteriorAnterior to Transverse axis for flexion and extension

Flexion 1. Ligamentum nuchae2. Tectorial membrane

Posterior neck muscles

Cervical Posterior Extension 1. Anterior longitudianal ligament

Thoracic Anterior Flexion 1. posterior longitudianal ligament

2. ligamentum flavum3. supraspinous ligament

Extensors

Lumbar Posterior Extension 1. Anterior longitudianal ligament

Sacroiliac joint

Anterior Flexion type motion

1. Sacrotuberous ligament2. Sacrospinous ligament3. Sacroiliac ligament

Hip joint Posterior Extension 1. Illiofemoral ligament Iliopsoas

Knee joint Anterior Extension 1. Posteripor joint capsule

Ankle joint

Anterior Dosrsiflexion Soleus

Deviation from optimal alignment in sagittal plane:•Minimizing energy expenditure and stress on supporting structures is one of the primary goals of any posture.

•Any changes in position or malalignment of one body segment will cause changes to occur in adjacent segments as well as changes in other segments as body seeks to adjust or compensate for the malalignment.

•If stresses are maintained over long periods of time:

Muscle may shortened: lose sacromeres, prevent full ROM

Muscle may lengthened: add sacromeres altering length-tension relationship

Stretching of ligament: reduces its ability to provide sufficient tension to protect or stabilize joints

Shortened ligaments: will limit ROM

•Prolong weight bearing stresses on joint surface increase cartilage deformation and interferes with nutrition of cartilage leading to early degenerative changes.

Foot and toes:

•Claw toes: characterized by hyperextension of MTP combined with flexion of PIP & DIP.

The proximal phalanx may subluxate dorsally on metatarsal head. A callus may develop on dorsal aspect of flexed phalanges.Causes: restrictive effect of shoes, ineffectiveness of intrinsic muscles, muscular imbalance, neuromuscular disorders and age related deficiency in plantar structures.

Hammer Toes: characterized by hyperextension at MTP, flexion at PIP and hyperextension at DIP.Flexor are stretched over MTP joint and shortened over IP joints.Extensors are shortened over MTP and lengthened over IP joints.If long and short toe extensors and lumbricals are paralyzed, the intrinsic and extrinsic toe flexors acting unopposed will buckle the PIP and DIP joints causing deformity

Flexed knee posture: LOG falls posterior to knee joint axes creating a flexion moment at knee.

Flexed knee erect standing postures are related to ankle and hip. It is accompanied by hip flexion and ankle dorsiflexion, the location of LOG also will be altered in relation to these joint axes. At hip, it lies anterior and at ankle it shifts slightly away from the joint axes.

Hyperextended knee posture (Genu recurvatum)LOG is located considerably anterior to knee joint axes, which tends to increase the extent of hyperextension and puts posterior joint capsule under considerable tension stress.

Prolong posture leads to lengthening of posterior capsule and cruciate ligaments leading to unstable joint.

Abnormal compression at anterior portion of knee joint may lead to degenerative changes.

Hyperextension at knee is usually caused by limited DF at ankle or by a fixed PF position of foot and ankle called equinus

Pelvis

Excessive anterior pelvic tilt:

•In a posture in which pelvis is excessively tilted anteriorly, lower lumbar vertebrae are forced anteriorly while upper lumbar vertebrae are forced posteriorly increasing lumbar anterior convexity.•Similarly, posterior convexity of thoracic and anterior convexity of cervical increases to bring the head over sacrum.•Lumbar discs are subjected to tension anteriorly and compression posteriorly.

Vertebral column:•Lordosis: abnormal increase in normal anterior convexities in either the cervical or lumbar regions of the vertebral column.

•Kyphosis: abnormal increase in posterior convexity of thoracic vertebral column.

It may develop as result of oPoor posture habitsoAs compensation for an increase in lumbar lordosisoDiseases such as TB and AS

Gibbus or hump back deformity: occurs as result of TB which causes vertebral fracture. It is easily recognized by Gibbus (hump) which forms by sharp posterior angulation in upper thoracic vertebral column.

Dowager’s hump is easily recognizable kyphotic condition found most often in post menopausal women having osteoporosis. The anterior aspect of bodies of a series of vertebrae collapse as a result of osteoporotic weakening. The vertebral body collapse causes an immediate lack of anterior support for a segment of thoracic vertebral column, which bends forward, causing an increase in posterior convexity and compression on anterior aspect of vertebral bodies.

Head:Forward head posture: •The head is positioned anteriorly at an increased distance from LOG and the normal anterior cervical convexity is increased with the apex of lordotic curve at a considerable distance from LOG compared to optimal posture.In forward head posture, the scapulae may rotate medially, and thoracic kyphosis may develop and overall body height may be shortened

Body segment LOG location Observation

Head Passes through middle of the forehead, nose and chin

Eyes and eras should be level and symmetrical

Neck/ shoulder Right and left angles between shoulders and neck should be symmetrical. Clavicles also should be symmetrical

Chest Passes through the middle of the xyphoid process

Ribs on each side should be symmetrical

Abdomen/ hips Passes though the umbilicus Right and left waist angles should be symmetrical

Hips/ pelvis Passes on a line equidistant from the right and left ASIS. Passes through the symphysis pubis

ASIS should be level

Knees Passes between knees equidistant from medial femoral condyles

Patella should be symmetrical and facing straight ahead.

Ankles/ feet Passes between ankles equidistant from the medial maleoli

Malleoli should be symmetrical and feet should be parallel.

Toes should not be curried, over lapping or deviated to one side.

Frontal plane analysis:

Body segment LOG location Observation

Head Passes through middle of the head, Head should be straight with no lateral tilting.

Angles between shoulder and neck should be equal

Arms Arm should hang naturally so that palms of the hand are facing sides of the body

shoulder./spine Passes along vertebral column in straight line which should bisects back into two equal halves

Scapula should lie flat against the rib cage, be equidistant from LOG and separated 4” in adult

Hips/ pelvis Passes though gluteal cleft of buttock and should be equidistant from PSIS

PSIS should be level, gluteal fold should be level and symmetrical

Knees Passes between knees equidistant from medial joint aspects

Knees are level

Ankles/ feet Passes between ankles equidistant from the medial maleoli

Heel cord should be vertical and malleoli should be level and symmetrical

Frontal plane analysis: post view

Deviations from optimal alignment

Pes Planus:•Flat foot characterized by a reduced or absent arch, may be either rigid or flexible•Rigid flat foot: medial longitudinal arch is absent in non-weight bearing, toe standing and normal weight-bearing situation.•Flexible flat foot: arch is reduced during normal weight bearing situation but reappears during toe standing or non-weight bearing situation.•In either type of pes planus, talar head is displaced anteriorly, medially and inferiorly. The displacement of talus causes depression of navicular bone, tension in plantar calcaneonavicular ligament and lengthening of tibilais posterior muscle.

Pes Cavus:

•A high medial longitudinal arch is called Pes Cavus, which is more stable position of than pes planus.

•Weight in pes cavus is borne on lateral border of foot and the lateral ligaments and peroneus longus muscle may be stretched.

•The cavus foot is unable to adapt to the supporting surface because the subtalar and transverse talar joints tend to be near or at locked supinated position.

Hallux Valgus:•In which there is a medial deviation of first metatarsal at tarsometatarsal joint and lateral deviation of phalanges at metatarsophalangeal joint•Most common cause is abnormal pronation in combination with forefoot adductors.

Genu Valgum (knock knee)•In genu valgum, the mechanical axes of lower extremities are displaced laterally.•The medial knee joint structures are subjected to abnormal tensile or distraction stress and lateral structures are subjected to abnormal compressive stress.•Patella may be laterally displaced and therefore predisposed to subluxation.

Genu Varum (bow leg)•This is a condition in which knees are widely separated when the feet are together and malleoli are touching.•Cortical thickening on medial concavity of both the femur and tibia may be present as a result of increased compressive force.•Patella may be displaced medially.•More commonly seen in Vit-D deficiency, renal rickets, osteochondritis and epiphyseal injury.

Squinting or Cross-eyed Patella•Patella is tilted or rotated a position, where the superior medial pole of patella faces medially and inferior pole points laterally.•It may be a sign of increased medial femoral tension.

Grasshopper eyed patella•It refers to a high laterally displaced position of the patella in which patella faces upward and outward.•The medially rotated position of patella is due to either feomarl retroversion or lateral tibial torsion.

Scoliosis:

•In optimal posture, the vertebral structures: ligaments and muscles are able to maintain the column in vertical alignment with little stress or energy expenditure.

•If one or more medial-lateral structures failed to provide adequate support, the column will bend to the side.

•The lateral bending will be accompanied by the rotation of the vertebrae because lateral flexion and rotation are coupled motion below the level of C2

vertebrae

•Consistent lateral deviations of a series of vertebrae from the LOG in one or more regions of the spine may indicate the presence of lateral spinal curvature in frontal plane called scoliosis.

•They are classified as functional and structural

The vertebral deviations in scoliosis may cause asymmetrical changes in body structures which can be detected through simple observation of body contours like: unequal waist angles, unequal shoulder level or unequal scapulae, rib hump and obvious lateral spinal curvature

Effects of age, pregnancy, occupation and recreation on posture:

Infants and children:

•Postural control in infants develops progressively during the first year of life from control of head, to control of body in sitting and then in standing.

•The child learns to maintain a certain posture usually through co-contraction of antagonist and agonist muscle around a joint and then is able to move in and out posture.

•Controlled mobility refers to the ability to move within posture where as skill refers to performance of activities like running, walking and hopping.

•The erect standing posture in infancy and early childhood differs somewhat from postural alignment in adult but by the time child reaches age of 10-11 years, postural alignment in erect standing position should be similar to adult alignment.

Elderly:

•Postural alignment in elderly shows a more flexed posture than in young adult.

•The flexed posture observed in some elderly is probably due to a number of factors that may be attributed to the aging process, to a combination of aging and sedentary life style.

•In kyphosis, the anterior trunk flexor muscles shorten as posteriorly located trunk extensors lengthen.

•Additional characteristics of posture in the elderly may be a forward head, which causes an increase in flexion in cervical region and increase in extension at atlanto-occipital joint.

•ROM at knees, hips, ankles and trunk may be restricted because of muscle shortening and disuse atrophy.

•Balance time and torque production decrease significantly with age.

Pregnancy:

•Normal pregnancies are accompanied by a weight gain, an increase in weight distribution in breast and abdomen, and softening of ligamentous and connective tissues.

•The location of woman’s COG changes because of the increase in weight and its distribution anteriorly.

•Consequently postural changes in pregnancy include an increase in lordotic curves in cervical and lumbar areas of vertebral column, protraction of shoulder girdle, anterior pelvic tilt and hyperextension at knees.

Occupation and recreation:

•Each particular occupational and recreational activity has unique posture and resulting in associated injuries.

•Bricklayers, surgeons, carpenters, and cashiers assume and perform tasks in standing postures for a majority of the working days.

•Secretaries, accountants, computer operators and receptionists assume sitting posture for a large portion of the day.

•Performing artists often assume asymmetrical posture while playing a musical instrument, dancing, or acting

•Many of the injuries sustained during both occupational and recreational activities falls into the category of “overuse injuries”. This type of injury is caused by repetitive stress that exceeds physiological limits of the tissues: muscles, ligaments, tendons are vulnerable to the effects of repetitive tensile forces, where as bones and cartilage are susceptible to injury from application of excessive compressive force.

It can be static or dynamicStatic balance test: double limb stance, single

limb stance, tandem stance, Romberg’s test, and sharpen Romberg’s test.

Dynamic posture control includes standing up, walking, turning, stopping and starting. Graded on 3 point ordinal ranking.

Standardized test for postural control are: functional reach testBerg balance scalePerformance orientated mobility assessmentGet up and go testTime up and go test

August 26, 2009