The spinal cord is a vital structure that connects your brain to the rest of your body. It extends from the lower part of the brain down to your lower back. The spinal cord relays information to your brain and helps it carry out many critical functions, including the movements of your limbs.
This article will break down the anatomy of the spinal cord, its vital functions, and some health conditions that can affect its functions.
What Is the Spinal Cord?
The spinal cord is a long, tube-like structure extending from the base of your brain (the brain stem). It’s made of a collection of nerves and is encircled and protected by the bones of the spine (vertebrae).
Spinal Cord Anatomy
The spinal cord is a vital part of the central nervous system, along with your brain. It’s around 50 centimeters long, though the length may vary in different individuals. The spinal cord is divided into four regions:
It is covered by the meninges, which consists of three layers:
- Dura mater. This is the tough, outermost layer tasked with protecting your spinal cord from injury.
- Arachnoid mater. This thin, transparent central layer gets its name from its spider-web-like appearance.
- Pia mater. The innermost layer of connective tissue is called the pia mater. It directly connects to your spinal cord.
The cervical (neck) and the lumbar (lower back) components of the spinal cord are comparatively larger than the other regions. The lowest part of the spinal cord is called the “cauda equina,” which in Latin means the “horse’s tail.” It received this name because the nerve bundle in this part resembles a horse’s tail.
The spinal cord is surrounded by cerebrospinal fluid, which suspends it within the 33 vertebrae of the spinal column. Small nerves from the spinal cord branch out from this cylindrical tube. They are called roots and move out through small openings between the vertebrae and connect to different body parts.
Spinal Cord Functions
One of the primary responsibilities of the spinal cord is to carry signals from the brain to different parts of the body. It does this through the nerves that connect your brain to other specific body parts. These nerve signals have three main roles. They:
- Regulate body movements. Your brain sends signals to other body parts through the nerves to carry out normal movements like walking, standing, running, etc. It also controls involuntary bodily functions such as your heartbeat, breathing, bowel, and bladder movements.
- Send sensory signals to the brain. The nerves also carry signals from different parts of your body to your brain. These include sensory information such as pain, heat, and pressure.
- Control your reflexes. The nerves in the spinal cord also control some reflex actions without involving your brain.
Spinal Cord Conditions
Any disruption of spinal cord activity due to injury or disease could lead to serious conditions, including the loss of motor and sensory functions. In severe cases, this loss could be permanent.
- Spinal fractures. When the bones in the neck, spine, and back break, that can cause spinal fractures. Fractures can occur due to trauma, accidents, or genetic conditions.
- Spinal deformities. These can occur due to conditions such as scoliosis and kyphosis that cause abnormal curvatures in the spine. Such deformities can also occur due to spinal fractures or other conditions like spondylolisthesis and ankylosing spondylitis.
- Ankylosing spondylitis. This is a type of arthritis that causes inflammation between the bones in the spine. Sometimes, inflammation also occurs in the joints where the spine and your pelvis meet. Men are more likely to encounter this condition.
- Spondylosis. The spine’s vertebrae and the discs between the spinal cord bones wear out in cases of spondylosis, which can occur in the cervical region (in which case it is called cervical spondylosis) or in the lumbar and thoracic regions ( in which case it is called lumbar spondylosis or thoracic spondylosis, respectively).
- Spinal stenosis. The spine narrows due to injury or a disease such as osteoarthritis, putting undue pressure on the spinal cord and the nerves.
- Herniated discs. A herniated disc is a condition where one of the gel-like discs between the vertebrae breaks and puts pressure on one of the nearby nerves. This may lead to other conditions, such as sciatica and back pain.
- Degenerative disc disease. Also known as osteoarthritis of the spine, this is a condition where the discs between the vertebrae become dry and wear out. This typically occurs in old age, but impact injuries can also be the cause.
- Spinal tumors. When there’s an unusual tissue collection in and around the spinal cord or the spinal column, it may become a tumor. Malignant (cancerous) tumors are more harmful and can occur when tumors from other parts of the body spread to the spine.
Spinal Cord vs. Vertebral Column
The spinal cord is often confused with the vertebral column, but the two are distinct. While the spinal cord is a soft layer of tissue consisting of nerves and cells, the vertebral column is a hard structure made of bone that covers the spinal cord and protects it.