How Paraplegia Affects the Lower Extremities

Paraplegia is an impairment of the lower parts of the body such as legs as a result of spinal cord damage. Such disability may also occur due to a congenital condition like Spina Bifida that interferes with the neural system of the spinal cord. The lower body parts affected by paraplegia are either lumbar, sacral, or thoracic regions (Shields, 2002). In addition, paraplegia may affect both arms – a condition called quadriplegia; if it affects only one limb the condition is called monoplegia. Paraplegia occurs due to spinal cord damage, which may result to the loss of movement ability, relaxation, and sensation below the area where the spinal cord is damaged. As a result, an individual may lose bowel control, bladder control, or suffer from sexual dysfunction.

Walsh (2004) suggests that paraplegia is mostly caused by traumatic injuries of the spinal cord and nervous tissue resulting to swelling and inflammation at the point of trauma. These may be a result of a road accident, for example. Young adults are in the risk group, and males suffer from the condition more frequently than females. Congenital and non-traumatic factors such as spinal scoliosis, tumors, or Spina Bifida can cause paralysis as well. Scoliosis refers to abnormal curving of the spinal cord bones. Spina Bifida may develop during birth where parts that make up the spinal do not come out together (Shields, 2002). In addition, direct injuries such as a cut to the spine may cause paraplegia, particularly when the vertebra is traumatized. Another factor that may entail paraplegia is abnormal twisting of the neck, head or back that may press or compress the spinal cord sideways, hence causing direct damage. Diseases such as spinal tuberculosis, spinal tumors, syphilis, poliomyelitis, and multiple sclerosis can act as causing factors of paraplegia as well. These illnesses damage spinal nerves which are irreparable, hence causing permanent paraplegia (Walsh, 2004).  Lastly, accumulation of fluid or blood which may cause spinal cord swelling or compression may also lead to paraplegia.

In the case of permanent paraplegia, a condition called muscle atrophy develops. The condition is characterized by increased metabolic disorders and reduced rate of metabolism. In addition, a traumatic and rapid loss of muscle mass occurs below the standard level. Reduction in muscle mass can result to increased fat storage in case the energy input is not adjusted relative to energy output or expenditure (Walsh, 2004). For example, a person with complete spinal cord injury will have reduced energy expenditure compared to an individual the healthy spinal cord. Permanent paraplegia may also affect muscular functioning, thus resulting to partial or complete loss of muscle functions that may be permanent. Loss of muscle functions will result to loss of postural, voluntary, and reflex movements (Shields, 2002). In addition, permanent paraplegia makes muscles soft and loose, making them unable to resist passive stretching. Also, muscle tone reduces which results to partial paralysis and awkward and stiff muscular movements due to damaged upper neuron system.

There are several nerves that provide motor innervation to the lower extremities. These include iliopsoas, femoral nerve, L23, and hip flexion. The second category of motor neurons involves quadriceps femoris, L34, knee extension and femoral nerve (Nathan, 1997). The third category consists of adductor longus, L3, and obturator nerve. The fourth type of motor nerves in lower extremities contains gluteus medius/minimus, L5, and superior gluteal nerve. The fifth category includes gluteus maximum, S1, and inferior gluteal nerve which come from underneath piriformis. The sixth type of motor nerves consists of S1, biceps femoris, hip extension, and sciatic nerve. The seventh category contains the following nerves: L4, tibalias anterior, and deep peroneal nerve. The eight one includes deep peroneal, L5, extensor hallicus longus (Nathan, 1997). The ninth category contains plantar flexion and eversion, peroneous longus and brevis,  and superficial peroneal nerve. The tenth category of motor innervation nerves to the lower extremities includes tibial nerve, L4, posterior tibialis. The last category contains tibial nerve, gastrocnemius, S1, and plantar flexion.

According to Nathan (1997), nerves of the foot and leg arise from spinal nerves as they descend to the thighs forming sacral plexus and lumbar plexus. The femoral nerves, obturator, saphenous, and lateral femoral nerves extend into the muscles and skin of leg and thigh.  These nerves further divide into smaller nerves to stimulate individual muscle sense pain, touch, cold, and warmth in the skin. Another motor innervation nerve is the sciatic nerve that provides nerve impulses to the body muscles and the skin.

Spinal cord injury affects voluntary motor control, hence movement is either impossible or very weak movement may be possible. It can also affect the autonomic motor control in which two cases may arise (Nathan, 1997). These cases are either increase in muscle activity as a result of the disruption between central nervous center and the spinal cord or hypotonia, which is the loss of tonus triggering the muscle.

Personal daily activities will be disrupted by spinal cord injuries as voluntary movements are not possible. In addition, the persons’ superficial sensibility is affected as well, for example, sense to pain, heat and cold, and also gross tactile discrimination (Nathan, 1997). Thus, people suffering from the disease will lack superficial sensitivity – a condition called anesthesia – that may cause multiple damages to the patient. As a result, people with spinal code injuries cannot effectively perform their daily routines.