The spinal cord is the body’s primary data highway, connecting the brain to the peripheral nervous system. This intricate bundle of nerves transmits signals that control movement, sensation, and automatic bodily functions. Understanding what a real spinal cord looks like involves exploring it through medical imaging and as a physical biological structure.
Visualizing the Spinal Cord with Medical Imaging
To see the spinal cord within a living person, medical professionals use non-invasive imaging. Magnetic Resonance Imaging (MRI) is the most effective method because of its ability to show soft tissues. An MRI uses a powerful magnetic field and radio waves to generate detailed, cross-sectional images of the body, allowing for visualization of the spinal cord’s shape, size, and position.
Another imaging tool is Computed Tomography (CT), which combines X-ray images from different angles to create comprehensive views. While CT scans are excellent for examining bone, they are less detailed than MRIs for soft tissues and are often used to assess the vertebrae for fractures. In some cases, a procedure called CT myelography, which involves injecting a contrast dye, is used to enhance the visibility of the spinal cord and nerve roots.
MRI images provide a clear window into the spinal column. A sagittal view (a side view) is useful for observing a section of the spine. In such an image, the spinal cord appears as a long, continuous, tube-like structure housed within the spinal canal. The clarity of MRI allows for the detection of subtle changes within the cord, making it the preferred method for many spinal evaluations.
Anatomy Seen in Medical Imaging
When viewing an MRI of the spine, several distinct structures are visible. The vertebrae are the individual bones stacked to form the spinal column, providing support and protection for the spinal cord. Between each vertebra lies an intervertebral disc, a soft cushion that acts as a shock absorber and allows for flexibility.
The spinal cord is situated within the spinal canal, a channel formed by the vertebrae. On a T2-weighted MRI, the spinal cord appears as a grayish structure, while the surrounding cerebrospinal fluid (CSF) is bright white, clearly outlining the cord. Branching from the sides of the spinal cord are the nerve roots, which are bundles of nerve fibers that pass through openings in the vertebrae to reach other parts of the body.
The Spinal Cord as a Biological Specimen
Outside of medical imaging, the spinal cord can be observed directly as a biological specimen in an academic or research setting. Its appearance is that of a soft, cylindrical bundle of whitish nerve tissue. The cord is flexible and has a delicate, gelatinous texture, reflecting its composition of nerve cells and fibers.
In an average adult, the spinal cord measures approximately 18 inches long, extending from the base of the brain to the lower back. It is not uniform in thickness and has two enlargements in the cervical (neck) and lumbar (lower back) regions. These thicker areas correspond to the increased number of nerve cells required to control the limbs. The specimen is encased in three protective membranes known as the meninges.