POSTURE

Definition: It is attitude or position of the body , the relative arrangement of body parts for a specific activity, or a characteristic manner of bearing one s body. It is attitude assumed by body either with support during muscular inactivity or by means of co- ordinate action of many muscles working to maintain stability or to from an essential basis which is being adapted constantly to the movement which is superimposed upon it.

Types of posture: 1.Inactive posture: Attitude adopted for resting or sleeping 2.Active posture: Integrated action of many muscles is required to maintain active posture. -static posture -dynamic posture

Static Posture: Static posture refers to the body and its segments are aligned and maintained in certain positions. E.g. standing, sitting, lying, and kneeling. Dynamic Posture: Dynamic posture refers to postures in which the body or its segments are moving E.g. walking, running, jumping, throwing, and lifting.

Primary goals of posture: Minimizing energy expenditure Minimizing stress on supporting structures Any change in position or mal alignment of one body segment will cause changes to occur in adjacent segments, as well as changes in other segments, as the body seeks to adjust or compensate for the mal alignment

Pattern of posture: Good posture : it is defined as state of musculoskeletal balance which protect the supporting structure of the body against injury or progressive deformity ,irrespective of attitude in which these structure are resting or working. Poor posture : it is defined as faulty relationship of the various parts of the body which produces increased strain on supporting structure & less balance of the body over base of support. by posture committee of american acedemy of orthopedic surgeon

Postural fault: It is posture that deviate from normal alignment but has no structural limitation. Postural dysfunction: It is posture that deviate from normal alignment with adaptive shortening of soft tissues & muscle weakness.

Various factor affecting posture: Age: Postural pattern change during life cycle. As position of lower extremity joints,development of spinal curves. Gender: Higher % of fat & wide pelvis in women Nutritional factor: Required for good structural & functional development , affect the growth before maturation &lead to fatigue after maturation , thus affect posture

Emotional status: Habits: poor postural habits Disease & disability: Occupation& recreation:

Postural Control Definition: It is a person s ability to maintain stability of the body and body segments in response to forces that threaten to disturb the body s equilibrium. Maintenance and control of posture depend on the integrity of the CNS, visual system, vestibular system, and musculoskeletal system

Reactive(compensatory) responses occur as reactions to external forces that displace the body s CoM . Proactive (anticipatory) responses occur as reactions to internally generated destabilizing forces that displace the body s CoM .

Goals of postural control1. To maintain the body s CoM over the BoS, 2. To control the body s orientation in space, 3. To stabilize the head with regard to the vertical so that the eye gaze is appropriately oriented.

Postural sway In the erect standing posture, little or no acceleration of the body occurs, except that the body undergoes a constant swaying motion called postural sway or sway envelope. With 4 inches base,12 in the sagittal plane , 16 in the frontal plane sway

Kinetics & kinematics of Posture In response to perturbations ,active internal forces employed to counteract the external forces that affect the equilibrium and stability of the body The external forces are inertia, gravity, and ground reaction forces(GRFs). The internal forces are produced by muscle activity and passive tension in ligaments, tendons, joint capsules, and other soft tissue structures

Ground Reaction Forces: Whenever the body contacts the ground, the ground pushes back on the body. This force is known as the GRF. The vector representing it is known as the ground reaction force vector (GRFV). Having three components: A vertical component force (along the y-axis), two force components directed horizontally in a medial-lateral direction (along the x-axis) & other horizontal force in an anterior-posterior direction (along the z-axis)

Coincident Action Lines : When the LoG passes directly through a joint axis, no external gravitational torque is created around that joint. if the LoG passes at a distance from the axis, an external gravitational moment is created. it is opposed by a counterbalancing internal moment

If the LoG is located anterior to a particular joint axis, the gravitational moment will tend to cause anterior motion of the proximal segment of the body. If the LoG is posterior to the joint axis, the moment will tend to cause posterior motion of the proximal segment of the body.

Equipment: Postural board with foot prints Plumb line Folding ruler with spirit level Set of blocks for limb length measurement Marking pencil Tape measure Test for muscle length & strength

Analysis of Posture Standing posture: A plumb line, or line with a weight on one end, dropped from the ceiling and passing through the external auditory meatus of the ear, used to represent the LoG.

Atlantooccipital Cervical Thoracic Lumbar Sacroiliacjoi nt Hip joint Knee joint Ankle joint

Anterior

Flexion

Posterior Anterior Posterior Anterior

Extension Flexion Extension Flexion

Posterior Anterior Anterior

Extension extension dorsi Flexion

Ankle: In the optimal erect posture, the ankle joint is in the neutral position, or midway between dorsiflexion and plantarflexion. The LoG passes slightly anterior to the lateral malleolus creates an external dorsiflexion moment & opposed by an internal plantarflexion moment EMG studies have demonstrated that soleus and gastrocnemius

Knee: In optimal posture, the knee joint is in full extension. the LoG passes anterior to the midline of the knee and posterior to the patella. creates an external extension moment & counterbalancing internal flexion moment created by passive tension in the posterior joint capsule and hamstring.

Hip: In optimal posture, the hip is in a neutral position. When the LoG passes slightly posterior to the axis of the hip joint, through the greater trochanter creates an external extension moment at the hip & opposed by internal flexion moment. EMG studies have shown activity of the iliopsoas muscle

Pelvis: in the optimal position, the pelvis is level with no anterior or posterior tilt In a level pelvis position, lines connecting the symphysis pubis and the anterior-superior iliac spines(ASISs) are vertical, and the lines connecting the ASISs and posterior-superior iliac spines (PSISs) are horizontal.

Sacroiliac Joints: in the optimal position, the LoG passes slightly anterior to the sacroiliac joints. The external gravitational moment cause the anterior superior portion of the sacrum to rotate anteriorly and inferiorly, whereas the posterior inferior portion tends to move posteriorly and superiorly opposed by passive tension in ligaments.

Lumbosacral Joints: The average lumbosacral angle measured between the bottom of the L5 vertebra and the top of the sacrum (S1) is about 30 In the optimal posture, the LoG passes through the body of the fifth lumbar vertebra & creates a slight extension moment at L5 to S1 opposed primarily by the anterior longitudinal ligament and the iliolumbar ligaments.

The Vertebral Column: the LoG passes through the bodies of the lumbar and cervical vertebrae and anterior to the thoracic vertebrae in the optimal posture. the gravitational moments tend to increase the natural curves in the lumbar, thoracic, and cervical regions.

Head: The LoG in relation to the head passes slightly anterior to axis of rotation for flexion and extension of the head creates an external flexion moment & counteracted by internal moments generated by activity of the neck extensors

Deviations from Optimal Alignment In the Sagittal Plane: Foot and Toes: Claw Toes The toes characterized by hyperextension of the metatarsophalangeal (MTP) joint & flexion of the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints Hammer Toes hyperextension of the MTP joint, flexion of the PIP joint, and hyperextension of the DIP joint.

Knee: Flexed Knee Posture The LoG passes posterior to the knee joint axes. Other consequences of a flexed-knee erect standing posture are related to the ankle and hip. Because knee flexion in the upright stance is accompanied by hip flexion and ankle dorsiflexion.

Hyperextended Knee Genu Recurvatum The LoG is located anterior to the knee joint axis. Increase in the external extensor moment at the knee and puts the posterior joint capsule under considerable tension stress & consequently, result in a more unstable joint.

Pelvis: Excessive Anterior Pelvic Tilt: pelvis is excessively tilted anteriorly, the lower lumbar vertebrae are forced anteriorly. The upper lumbar vertebrae move posteriorly to keep the head over the sacrum, thereby increasing the lumbar anterior convexity. The posterior convexity of the thoracic curve increases and becomes kyphotic to balance the lordotic lumbar curve and maintain the head over the sacrum. Similarly, the anterior convexity of the cervical curve increases to bring the head back over the sacrum.

Vertebral Column:

Lordosis and Kyphosis The term lordosis refers to the normal sagittal plane anteriorly convex curves in the cervical and lumbar regions of the vertebral column. The term kyphosis refers to the normal sagittal plane posteriorly convex curves in the thoracic and sacral regions of the vertebral column.

Head: Forward Head Posture the head is positioned anteriorly and the normal anterior cervical convexity is increased

Frontal Plane Optimal AlignmentAnterior Aspect Passes through middle of the forehead, nose and chin. Passes through the middle of the xyphoid process. Passes through the umbilicus (navel). Passes on a line equidistant from the right and left anterior superior iliac spines. Passes through the symphysis pubis. Passes between knees equidistant from medial femoral condyles. Passes between ankles equidistant from the medial maleoli.

Posterior Aspect Passes through middle of head. Passes along vertebral column in a straight line. Passes through gluteal cleft of buttocks and should be equidistant from posterior superior iliac spines. Passes between the knees equidistant from medial joint aspects. Passes between ankles equidistant from the medial malleoli.

Deviations from Optimal Alignment in the frontal plane: Foot and Toes Pes Planus (Flat Foot) characterized by a reduced or absent medial arch Pes Cavus The medial longitudinal arch of the foot is unusually high.

Genu valgum (knock knee) the mechanical axes of the lower extremities are displaced laterally. The patella may be laterally displaced and therefore predisposed to subluxation. Genu varum (bowleg ) knees are widely separated when the feet are together and the malleoli are touching. the patellae may be displaced medially.

Squinting or cross-eyed patella: patella that faces medially Grasshopper-eyes patella refers to a high, laterally displaced position of the patella in which the patella faces upward and outward. In both,patella tracking may be affected

Vertebral Column Scoliosis the vertebral column is vertically aligned and bisected by the LoG. lateral deviations of a series of vertebrae from the LoG in one or more regions of the spine indicate the presence of a lateral spinal curvature in the frontal plane called a scoliosis

Common impairment/problems associated with postural dysfunction: Pain : from stress to sensitive structure & from muscle tension Decrease range of motion : From flexibility imbalance Muscle weakness & poor muscle endurance : From sustained faulty posture or disuse Altered kinesthetic awareness of normal alignment & control: from prolonged faulty postural habits

Treatment goals & plan of care:Treatment goal Relieve pain & muscle tension Plan of care External postural support if necessary. Muscle relaxation

Restore range of motion Restore muscle strength , endurance & function

Specific stretching & flexibility exercise Specific resistive exercises Endurance exercises

Retrain kinesthetic awareness & control of normal alignment

Reinforcement techniques

Kypho-lordotic posture

Postural fault Forward head

Anatomical position of joint Cervical spine hyperextension

Muscle in shortened position

Muscle in lengthened position

treatment

Cx spine Cx spine flexor extensors, upper trepezius &levator Serratus Middle & lower anterior, trapezius pectoralis minor, upper trapezius Shoulder adductor, pectoral minor, upper tapezius, inter costal Lower back erector spinae, hip flexor Middle & lower Trapezius, thoracic spine extensor Abdominals, hip extensor

Forward shoulder

Scapulae abducted & elevated

Steretching of tight muscles & strengthening of weak muscles

kyphosis

Thoracic spine flexion

lordosis

Lumber spine hyperextension, pelvis anterior tilt,hip joint flexion

Flat back posture

Postural fault

Anatomical position of joint

Muscle in shortened position

Muscle in lengthened position

treatment

Flat back posture

Lumber spine flexion Pelvis posterior tilting Hip joint extension

abdominals, hip extensor

Lower back erector spinae, hip flexor

Lower back & hip flexor strengthening

Sway back posture

Postural fault

Anatomical position of joint

Muscle in shortened position

Muscle in lengthened position Lower abdominals, hip flexor

treatment

Sway back posture

lumber spine upper flexion abdominals, Pelvis posterior hip extensor, tilting, Inter costal Hip joint extension

Lower abdominals & hip flexor strengthening

POSTURE acronym for easy reference: P: Pelvis in neutral, with weight distributed O: on the whole foot. S: Stable joints; T: Tight abdominals; U: upright ribs; R: retracted shoulders and E: ear over shoulder.

Millitary/lordotic posture

Postural fault

Anatomical position of joint

Muscle in shortened position

Muscle in lengthened position

treatment

Hyperextended Of knee

Knee hyperextension Ankle planter flexion Knee flexion,ankle dorsiflexion

Qudriceps, soleus

hamstring

Strengthening of hamstring

Flexed knee

hamstring

Qudriceps, soleus

Check length of hip flexor,stretching of knee flexor if tight

Postural fault of feet

Anatomical position of joint

Muscle in shortened position

Muscle in lengthened position

treatment

Pronation

Foot eversion

Peroneal & toe extensor

Tibials posterior & long toe flexor peroneal

Inner wedges on heels & strengthen inverters Outer wedges on heels &strengthen everters

Supination

Foot inversion

tibialis

Eyes and ears should be level and symmetrical. Right and left angles between shoulders and neck should be symmetrical. Clavicles also should be symmetrical. Ribs on each side should be symmetrical. Right and left waist angles should be symmetrical. Anterior superior iliac spines should be level. Patella should be symmetrical and facing straight ahead. Malleoli should be symmetrical, and feet should be parallel. Toes should not be curled, overlapping, or deviated to one side. In anterior view of the human body, the LoG, in optimal posture, divides the body into two symmetrical parts.

Head should be straight with no lateral tilting. Angles between shoulders and neck should be equal. Arms should hang naturally so that the palms of the hands are facing the sides of the body. Scapulae should lie flat against the rib cage, be equidistant from the LoG, and be separated by about 4 inches in the adult. The posterior superior iliac spines should be level. The gluteal folds should be level and symmetrical. Look to see that the knees are level. The heel cords should be vertical and the malleoli should be level and symmetrical.

Basic elements of postural control: Muscle Synergies / postural responses : Synergies are centrally organized patterns of muscle activity that occur in response to perturbations of standing postures they are involuntary reaction. perturbation It is sudden change in conditions that displaces the body posture away from equilibrium. The perturbation can be sensory or mechanical.

Muscle Synergies: 1) Fixed-Support Synergies: Patterns of muscle activity in which the BoS remains fixed during the perturbation and recovery of equilibrium. Stability is regained through movements of parts of the body, but the feet remain fixed on the BoS .

The ankle synergy The ankle synergy consists of discrete bursts of muscle activity on either the anterior or posterior aspects of the body that occur in a distal-to-proximal pattern in response to forward and backward perturbation. The hip synergy The hip synergy consists of discrete bursts of muscle activity on the side of the body opposite to the ankle pattern in a proximal-to-distal pattern of activation in response to forward and backward perturbation.

2) Change-in-Support Strategies The change-in-support strategies include stepping (forward, backward, or sidewise) and grasping (using one s hands to grab a bar or other fixed support) Only synergies that are maintaining stability in case of a large perturbation

3) Head-Stabilizing Strategies used to maintain the head during dynamic tasks modification of head position in responce to displacements of the body s CoG. The HSS strategy is one in which the head position are independent of trunk motion. The HST strategy is one in which the head and trunk move as a single unit.