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| a pathology frequently produces patterns of movement or applied force that are | clearly different |
| to walk, the locomotor system must be able to accomplish: | each leg in turn must be able to support the body weight without collapsing - balance must be maintained during single leg stance - the swing leg must be able to advance to a position where it can take over the supporting role - sufficient power must be provided to make the necessary limb movements. in normal walking, all of these are performed without any apparent difficulty and with modest energy consumption |
| in many forms of patholgical gait locmotor system can only accmplish things needs to to walk by means of | abnormal movements that usually increase energy consumption |
| a functional abnormality exists when | the tissues do not allow sufficient passive mobility for the individual to attain the normal postures and ranges of motion used in walking |
| pathological gait may result from...and may also result from | a disorder in any part of the system (i.e. brain, spinal cord, nerves, muscles, joints, etc.). pathological gait may also result from the presence of pain |
| it is important to note that an abnormal movement may be performed for one of two reasons: | - the subject has no choice, the movement being ‘forced’ on them by weakness, spasticity or deformity - the movement is a compensation which the subject is using to correct for some other problem that needs to be identified |
| contracture | reduction in the range of motion of a joint due to a restriction by elastic connective tissue |
| spasticity | involuntary resistance of muscles to being stretched |
| paralysis | loss of ability to contract a muscle voluntarily |
| lateral trunk bending | bending the trunk towards the side of the supporting limb during the stance phase is known as ipsilateral lean or Trendelenburg gait Lateral Trunk Bending |
| purpose of lateral bending | the purpose of this maneuver is generally to reduce the forces in the abductor muscles and hip joint during single leg stance |
| during double double support | the trunk is generally upright but as soon as the swing leg leaves the ground, the trunk leans over towards the side of the stance leg returning to upright at the beginning of the next double support phase |
| for double double support to work 4 conditions must be met which are. if one ore more of these conditions is not met the subject may compensate with.. | absence of significant pain on loading - adequate strength of the hip abductors - a sufficiently long moment arm for the hip abductors - a solid and stable fulcrum in or around the hip joint. compensate with lateral trunk bending |
| Conditions In Which lateral trunk bending Is Adopted | hip pain (as in osteoarthritis or rheumatoid arthritis) - pain experienced usually depends on the force transmitted though the joint - lateral trunk bending reduces the total joint forces - thus Trendelenburg gait usually adopted • hip abductor weakness - abductor muscles may be unable to stabilize pelvis during stance - lateral trunk bending reduces the joint moment |
| abnormal hip joint (ltb) | three conditions will lead to difficulty in stabilizing the pelvis (congenital dislocation of the hip, coxa vara and slipped femoral epiphysis) - in each of these, the effective length of the gluteus medius is reduced ( i.e. greater trochanter moves upwards towards the pelvis brim) - since muscle is shortened, it is unable to function efficiently and thus cannot generate sufficient tension - in CDH and slipped femoral epiphysis, the normal hip joint is effectively lost (i.e. abnormal joint is more laterally placed producing a reduced lever arm for the abductor muscles) - in many cases, the false hip joint becomes arthritic |
| wide walking base (ltb) | - if the walking base is abnormally wide, there is generally a problem with stability during single leg stance - rather than tip the whole body to maintain balance, lateral bending of the trunk is used to keep COM over the support limb - this is usually done during stance phase on both sides leading to bilateral trunk bending (waddling gait) |
| unequal leg length (ltb) | with an unequal leg length, the pelvis tips downwards on the side of the shortened limb as the body weight is transferred to it - the pelvic obliquity is accompanied by a compensatory lateral bend of the trunk |
| other infirmities leading to lateral trunk bending | adductor contracture, scoliosis, stroke |
| anterior trunk bending | in bending the trunk forward, the subject flexes their trunk forwards early in the stance phase |
| if only one limb affected in anetior turnk bending the turnk is | if only one limb is affected, the trunk is straightened again around the time of opposite initial contact |
| if both limbs are affected in anterior trunk bending | the trunk is kept flexed throughout the gait cycle |
| anterior trunk bending is genrally a compenstation for | an inadequacy of the knee extensor. |
| posterior trunk bending is...and is a compensation for | in early stance, the whole trunk bends backward.is a compensation for ineffective hip extensors |
| incrased lumbar lordosis | only an abnormality if the lordosis is used to aid walking in some way. |
| functional leg discrepancy | one or both legs are unable to adjust to the appropriate length for a particular phase of the gait cycle |
| to overcome a functional leg length discrepancy, an individual may adopt four closely related abnormalities | circumduction, hip hiking, steppage and vaulting |
| circumduction adoption | swing phase of other limb is usually normal • usually occurs with weak hip flexors • uses hip abductors to act as hip flexors while the hip joint is extended |
| hip hiking | pelvis is lifted on side of swinging limb • pelvis lifted by contraction of spinal muscles and the lateral abdominal wall • advancing the limb may also be helped by posterior trunk bending • commonly used in slow walking with weak hamstrings since the knee tends to extend prematurely thus making the leg too long towards the end of the swing phase |
| steppage | consists of exaggerated knee and hip flexion to lift foot higher than usual for increased ground clearance • used to compensate for foot drop |
| vaulting | increased if the subject goes up on the toes of the stance phase limb • causes an exaggerated vertical movement of the trunk • vaulting is a stance phase modification • commonly used in slow walking with hamstring weakness as the knee tends to extend too early in the swing phase |
| abnormal hip rotation | an abnormal rotation of the hip involves the whole leg with the foot showing an abnormal adduction or abduction alignment • may involve both stance and swings phases • results from one of three causes: - problem with the muscles producing hip rotation - fault in the way the foot contacts the ground - as a compensation to overcome another problem |
| mbalance of medial and lateral hamstrings is another common cause of | hip rotation. weakness of biceps femoris or spaticity of medial hamstrings will cause internal rotation - spasticity of biceps femoris or weakness of medial hamstrings will cause external rotation |
| a number of foot disorders can produce an | abnormal rotation of the hip. foot inversion will internally rotate whole limb on weight bearing - foot eversion will externally rotate the limb Kin 311 – Anatomy of Human Motion • external rotation may be used as a compensation for quadriceps weakness to alter the direction of the line of force through the knee • may be used as an alternative to anterior trunk bending • external rotation may also be used to facilitate hip flexion using the adductors as flexors (if hip flexors are weak) • individuals with weak triceps surae may externally rotate the limb thus permitting the use of the peroneals as plantar flexors |
| pes equinus | forefoot is fixed in plantar flexion usually through spasticity of the plantar flexors pes equinus • in less severe cases, the foot is placed on the ground flat but in more severe cases, the heel never touches the ground • GRF vector is displaced anteriorly, an increased external extensor knee moment occurs |
| pes valgus | excessive medial contact as a result of a weakness of the invertors or spasticity of the the evertors • medial side of the foot drops and takes most of the body weight • can be due to a valgus deformity of the knee |
| pes equinovarus | excessive lateral foot contact in which the medial border of the foot is elevated or the lateral border is depressed • combines equinus with varus producing a curved foot with all of the load borne by the outer border of the forefoot • this deformity is sometimes referred to as club foot |
| insufficient push off | • weight primarily taken on the heel and there is no push off phase • the whole foot is lifted off the ground at once • the main cause is a problem with the triceps surae or the achilles tendon • weakness or paralysis of the intrinsic muscles of the foot may prevent the foot from taking the load on the forefoot • may result from just about any foot deformity • may result from pain in forefoot |
| Abnormal Foot Rotation | pathological toe in or toe out may be produced by deformity of the foot or the internal or external hip rotation • results in GRF to be in an abnormal position relative to the leg • if foot is internally rotated, the GRF is more medial than normal generating external adductors moments at the ankle and knee • with toeing in or out, the GRF during terminal stance and preswing will be more posterior than normal • this reduces the lever arm for the triceps surae to produce an internal plantar flexion moment |
| asymmetric rhythmic disturbance shows | a difference in the timing between one stride and the next |
| irregular rhythmic disturbance shows differences between | one stride and the next |
| an antalgic gait patter is a | is a modification that reduces the amount of pain that is experienced (usually as little time as possible is spent on the painful limb and a longer time on the pain-free limb) |
