What is the spinal cord and what is its main function?

The spinal cord is a cylindrical extension of the central nervous system, about 45 cm long, that runs from the foramen magnum to between the L1 and L2 vertebrae. Its primary functions are to transmit information between the brain and the body and to execute reflexes.

What are the key external features of the spinal cord?

Key external features include the conus medullaris (tapered lower end), fissures and sulci (like the anterior median fissure), and nerve roots (31 pairs of spinal nerves). Below the conus medullaris, the cauda equina is a bundle of nerve roots in the cerebrospinal fluid.

How is the spinal cord organized internally?

Internally, the spinal cord has a central grey matter shaped like an H, containing neurons, and peripheral white matter organized into columns. The grey matter includes horns for motor and sensory functions, while the white matter contains ascending and descending tracts.

What are the main ascending and descending tracts in the spinal cord?

The main tracts are descending tracts (e.g., corticospinal) for motor signals from brain to spinal cord, and ascending tracts (e.g., spinothalamic) for sensory information from body to brain. They are named by their origin and destination.

What are the clinical implications of spinal cord lesions?

Lesions can cause specific syndromes, such as Brown-Séquard syndrome from hemisection, leading to ipsilateral motor and proprioception loss with contralateral pain/temperature loss, and syringomyelia affecting crossing spinothalamic fibers, causing bilateral pain and temperature loss.

How is the spinal cord supplied with blood?

Blood supply comes from the anterior spinal artery (supplies anterior two-thirds), posterior spinal arteries (supply posterior one-third), and segmental arteries like the arteria radicularis magna. Venous drainage goes through longitudinal veins to the internal vertebral plexus.

What is the difference between grey and white matter in the spinal cord?

Grey matter is central and H-shaped, containing neuron cell bodies for processing (e.g., in horns). White matter is peripheral, composed of myelinated fibers in columns that form tracts for transmitting signals up and down the cord.

Spinal Cord – Grey Matter, White Columns & Major Tracts

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