Human Anatomy

Spinal cord

A crucial structure that enables communication between the brain and the body, playing a key role in the nervous system.

The spinal cord is a long, tubular bundle of nervous tissue encased within the vertebral column. It extends from the base of the brainstem down to the lower back and is responsible for transmitting signals between the brain and various parts of the body. This structure is protected by the vertebrae and is encased in three membranes known as the meninges.

Terminologia Anatomica

medulla spinalis

System

Nervous system

Function

The primary function of the spinal cord is to facilitate communication between the brain and the peripheral nervous system. It serves as a conduit for motor commands originating from the brain, allowing for the control of voluntary and involuntary movements. Additionally, the spinal cord is integral to reflex actions, as it can process certain stimuli independently of the brain. When a stimulus is detected, such as touching a hot surface, sensory information is relayed to the spinal cord, which quickly sends a response back to the muscles, resulting in a rapid reaction. Thus, the spinal cord not only enables voluntary motions but also plays a critical role in protecting the body through quick, reflexive actions. Furthermore, the spinal cord contains various types of neurons and neural circuits that enhance the coordination of movements and the integration of sensory information.

Location

The spinal cord begins at the foramen magnum, where it connects with the medulla oblongata of the brain and travels down the vertebral canal through the vertebral column. It extends approximately 42 to 45 centimeters in length in adults and terminates near the first or second lumbar vertebra, forming the conus medullaris. From this point, a collection of nerve roots known as the cauda equina continues downward within the vertebral canal. The arrangement of the spinal cord segments correlates with the vertebral structure, as it is divided into regions—cervical, thoracic, lumbar, sacral, and coccygeal—which correspond to specific spinal nerves arising from each segment.

Did You Know?

The spinal cord contains 31 pairs of spinal nerves that branch out to various parts of the body, each responsible for different regions and functions.
Despite its relatively small size, the spinal cord has over a billion neurons that facilitate rapid communication throughout the body.
Injuries to the spinal cord can lead to varying degrees of paralysis, highlighting its vital role in motor control and sensation.
The spinal cord can also adapt through a process known as neuroplasticity, allowing for recovery or compensation after injury.
Reflex movements can occur even if the brain is not involved, showcasing the spinal cord's autonomous capabilities.