Causes of a spinal cord injury
A spinal cord injury occurs when something interferes with the function or structure of the cord. This can include the consequences of a disease or trauma that causes excessive stretching of the nerves, a blow, the pressure of the bones of the vertebrae against the spinal cord, a shock wave, electrocution, tumors, infections, intoxications, lack of oxygen (ischemia), cutting or tearing of the nerves.
Spinal cord injury can occur during the development of the fetus, from trauma, or from medical conditions.
The results of a spinal cord injury can look different depending on the type and location of the injury. The most common is motor and sensory loss and a reduction in the rate of functioning of some of the internal organs of the body (autonomic nerve function) below the level of the injury.
In general, the higher up the spinal cord an injury is, the more functions, sensations, and internal body functions will be affected.
An injury that affects all four limbs is called tetraplegia (it used to be called quadriplegia). The significance of these injuries goes far beyond simply the movement of the arms and legs, as sensation and all body systems are affected.
Other types of spinal cord injury
There are other less common types of spinal cord injuries that affect specific areas of the cord.
Anterior spinal cord syndrome (sometimes called ventral cord syndrome) is caused by lack of blood flow or lack of oxygen (infarction) to the front two-thirds, but not the back, of the spinal cord and part of the brain called the medulla oblongata.
The result is loss of motor, pain, and temperature sensations, but where the body is in space (proprioception) and vibration sensations remain from the level of injury downwards.
People with anterior cord syndrome will notice their body position by visually observing the environment, rather than feeling where the body is located.
Central cord syndrome most often results from a fall with excessive stretching (hyperextension) of the neck. There is a loss of function from the neck to the nipple line, including the arms and hands.
The torso has variable function and sensation. Lower body functions are not affected, but there is a variable to total loss of sensation.
People with this type of injury often retain the ability to walk but may have poor balance. It is a common type of injury in older people due to the decrease in flexibility that comes with age.
To understand the physiology of the spinal cord
There are two main parts in the nervous system one is, the central nervous system (CNS) and the peripheral nervous system (PNS). The central nervous system (CNS) comprises the brain and the spinal cord, which is the nerve center of the body.
The brain instantly generates, interprets, and responds to messages that are sent to and from the body through the spinal cord. Without this unit of communication, the body’s nerves, called the peripheral nervous system (PNS), cannot inform the brain or respond with actions or feel sensations.
Nerve cells or neurons comprise a cell body with numerous branch-like projections called dendrites; one of the projections from the cell body is long and is called the axon.
Axons carry messages out of the cell body; Spinal cord axons carry signals down from the brain (along descending pathways) and up to the brain (along ascending pathways).
Cells that control spinal cord function
Several types of cells carry out the functions of the spinal cord, including the following:
- Large motor neurons have long axons that control the skeletal muscles of the neck, torso, and extremities.
- Sensory neurons called dorsal root ganglion cells, or afferents, carry information from the body to the spinal cord and are found immediately outside the spinal cord.
- Cells that help integrate information and generate coordinated signals that control muscles are called spinal interneurons; these cells are entirely within the spinal cord.
- Support cells (called glia) far outnumber the neurons in the brain and spinal cord and perform many essential functions; They produce substances that allow neuronal survival and influence the growth of axons. However, they can also impede recovery after injury; some glial cells become reactive and thus contribute to the formation of growth-blocking scar tissue after injury.
- There is a specific type of glial cell, the oligodendrocyte, which generates the myelin sheaths that insulate axons and improve the speed and reliability of nerve signal transmission.
- Other large, star-shaped glial cells regulate the composition of the fluids that surround nerve cells; some of these cells, called astrocytes, also form scar tissue after injuries.
- There are other smaller cells that are activated in response to injury and help clean up waste products called microglia.
How is a spinal cord injury diagnosed?
Imaging using MRI or CT scans will provide information about a spinal cord injury, including the type and level of trauma. This may not be consistent with clinical examination, as the injury may be at one level and the level of function may indicate a higher level of injury due to swelling and other medical or trauma complications.
To assess the functional results of spinal cord injury, a physical exam is done.
Spinal cord injury is assessed using the International Standards for Neurological Classification of SCI (ISNCSCI) and the same scale should be used to assess spinal cord injury each time in order to track the outcome. progress accurately.