Disorders That Immobilize Lower Limbs

Many types of orthopedic disorders can cause such severe paralysis of the lower limbs that the use of a wheelchair or similar device is required to achieve locomotion. The two types of such disorders a physical therapist most frequently encounters are traumatic spinal cord injuries and spinal bifida.

Injury to the spinal cord affects the innervations of muscles. The higher the level of injury, the less will be the amount of muscle movements available to the affected person. Because groups of muscles are innervated from nerves emerging at particular level of the spinal column, it is possible to specify the limits of muscle action remaining to individuals who suffer spinal cord injury at a specific vertebra.

When the cord is severed at or above the third cervical vertebra, then death results. Partial lesion in this area creates weakness over the entire body.

Complete severance of the cord above the second thoracic vertebra (T-2) results in involvement of the upper and lower limbs. The term for this condition is quadriplegia, meaning all limbs are affected. Complete severance at the second thoracic vertebra (T-2) or below results in paraplegia (involvement of only the lower trunk and legs).

The person with n injury just below the fourth cervical vertebra has use of only the neck muscles and the diaphragm (the main muscle of respiration). Upper limb function is possible only with an electrically powered assistive device that moves the arm and opens and closes the hand.

Those who sustain injury below the fifth cervical vertebra retain use of the neck muscles, diaphragm, deltoid muscles of the shoulder, and biceps of the arms. Persons with this type of injury can perform many activities with their arms: they’re able to groom themselves, help apply their braces and push their wheelchair for short distances.

A person with a functional sixth cervical vertebra has the use of the wrist extensors in addition to the movements retained by those with higher levels of injury. Those with injuries at this level can in addition push the wheelchair for long distances and make use of the overhead trapeze (a bar hung overhead to be grasped with the hands as an aid in moving the body). Some very adroit individuals with this injury are able to drive a car with hand controls.

When the injury is below the seventh cervical vertebra, the major additional functions that remain are extension of the elbow and flexion and extension of the fingers. Movement of the hand is not completely normal because the intrinsic muscles of the hand do not function. The person with this level of injury can do pull-ups, pushups, and grasp and release. Consequently, the enabled person can be fairly independent in manipulating the wheelchair and in transferring from one place to another.

Individuals with lesions in the first through the ninth thoracic vertebrae have total movement capacity in the arms but none in the legs (the condition being called paraplegia). Control remains of some of the muscles of the upper back, the abdominal muscles and the muscles of the ribs. Complete control of the wheelchair is possible, as are self-feeding and grooming. Although standing is possible by use of long leg braces with pelvic bands, ambulation is very limited.

Those with a separation of the spinal cord in the lower thoracic upper lumbar level (T-10 to T-12 inclusive) have the movement potential of all types described above and possess complete abdominal muscle control as well as control of all the muscles of the upper back. Complete innervations of the abdominal muscles makes walking feasible with the support of long leg braces.

The lumbar levels one through three innervate the muscles of the hip joint that flex the thigh. The fourth level of the lumbar also innervates the muscles of flexion of the hip and together with the fifth level innervates all the muscles of the lower leg and the muscles that extend the hip. Those with a lesion at the upper lumbar levels have fairly good walking ability. With injuries below the fifth level the voluntary muscles of the lumbar region are not affected.

The sacral level (S-1 to S-5 inclusive) supplies nerves to the muscles of the pelvic girdle, the bladder, the anus and the external genitals. The disabled persons with the lesion in this area or at any level above it do not have bladder or bowel control.

Date: 2016-01-03; view: 891