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Spinal cord

The spinal cord is a cylindrical structure of central nervous system tissue that extends from the medulla oblongata at the base of the brain down through the vertebral canal, ending at the conus medullaris around the L1–L2 vertebral level. It is protected by vertebrae, meninges, cerebrospinal fluid (CSF), and surrounding epidural fat, which provide cushioning and structural support. The spinal cord contains gray matter, which houses neuronal cell bodies, and white matter, composed of myelinated axons that transmit signals to and from the brain. It is organized into segments corresponding to spinal nerves, each controlling motor, sensory, and autonomic functions in specific body regions.

The spinal cord serves as the main communication pathway between the brain and the peripheral nervous system, relaying motor commands, sensory information, and reflex signals. It also contains spinal reflex circuits that mediate rapid involuntary responses. Understanding the anatomy, function, and imaging appearance of the spinal cord is critical for radiologists, neurologists, and neurosurgeons, especially when evaluating trauma, tumors, infections, demyelinating diseases, or degenerative disorders.

Synonyms

  • Medulla spinalis

  • Spinal medulla

  • Cord of the spinal column

  • Vertebral cord

Function

  • Conducts motor signals from the brain to peripheral muscles

  • Conducts sensory signals from the body to the brain

  • Mediates reflexes via spinal reflex arcs

  • Supports autonomic functions such as bladder and bowel control

MRI Appearance

T1-weighted images:

  • The spinal cord appears intermediate signal intensity, slightly darker than surrounding fat in the epidural space.

  • Cerebrospinal fluid (CSF) around the cord appears hypointense, creating a natural contrast with the cord.

  • White matter is slightly darker than gray matter, allowing subtle internal differentiation in high-resolution images.

  • Pathology such as tumors, demyelination, or infarction may appear hypo- to isointense, with contrast enhancement highlighting lesions.

T2-weighted images:

  • CSF appears bright hyperintense, outlining the spinal cord clearly.

  • The cord itself shows intermediate signal, while edema, demyelination, or tumors appear hyperintense, making abnormal areas conspicuous.

  • T2 is particularly useful for detecting syringomyelia, myelitis, or intramedullary tumors.

STIR (Short Tau Inversion Recovery):

  • Suppresses fat signal from epidural and paravertebral fat, enhancing visualization of cord pathology.

  • Normal cord remains intermediate signal, while edema, inflammation, or tumors appear bright hyperintense, even if subtle.

  • Valuable for detecting post-traumatic changes, demyelination, or early neoplastic infiltration.

CT Appearance

  • The spinal cord itself is soft tissue density and not directly well-visualized without contrast.

  • The surrounding vertebral bodies and laminae are hyperdense, clearly defining the vertebral canal.

  • CT is particularly useful for assessing vertebral fractures, canal stenosis, calcified lesions, or bony deformities affecting the cord.

  • Epidural hemorrhage or calcified lesions may be identified as abnormal soft tissue densities within the canal.

MRI images

Spinal cord mri axial

MRI images

Spinal cord mri sag image

CT images

Spinal cord ct axial image

MRI image

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CT image

Spinal cord CT axial anatomy image-img-00000-00000