The main trunk or bundle of nerves running down the spine through holes in the spinal bone (the vertebrae) from the brain to the level of the lower back.
Part of the central nervous system, running from the medulla oblongata to the filum terminale, in the vertebral canal of the spine.
Major part of the central nervous system, which conducts sensory and motor impulses to and from the brain and is a site of reflex activity. It is a cylindrical tube, extending from the base of the brain through the vertebral canal to the upper part of the lumbar region. It has an inner core of gray matter, containing mostly nerve cells, surrounded by white matter with nerve fibers. The entire cord is surrounded by meninges (protective membranes). From it arise 31 spinal nerves.
Major nervous tissue originating at the base of the skull and terminating at the area between the first and third lumbar vertebra.
A ropelike elongation of nerve tissue that extends down the back from the brain and is enclosed within the bones of the spine. The brain and spinal cord are the two main structures of the central nervous system, which controls and coordinates all of the body’s functions and activities.
The portion of the central nervous system enclosed in the vertebral column, consisting of nerve cells and bundles of nerves connecting all parts of the body with the brain. It contains a core of gray matter surrounded by white matter. It is enveloped in three layers of membrane, the meninges, and extends from the medulla oblongata in the skull to the level of the second lumbar vertebra. From it arise 31 pairs of spinal nerves.
This is the lower portion of the central nervous system which is situated within the spinal column. Above, it forms the direct continuation of the medulla oblongata, the part of the brain directly above the foramen magnum, the large opening in the base of the skull. Below, the spinal cord extends to about the upper border of the second lumbar vertebra, where it tapers off into a fine thread, known as the filum terminale, that is attached to the coccyx at the lower end of the spine.
Part of the central nervous system, the spinal cord is an ovoid column of nerve tissue 40 to 50 cm long that extends from the medulla to the second lumbar vertebra; it is within the spinal (vertebral) canal, protected by bone, and directly enclosed in the meninges. The center of the cord is gray matter in the shape of the letter H; it consists of the cell bodies and dendrites of neurons. The ventral (anterior) horns of the gray matter contain cell bodies of somatic motor neurons; the dorsal (posterior) horns contain cell bodies of interneurons. The white matter is arranged in tracts around the gray matter. It consists of myelinated axons that transmit impulses to and from the brain, or between levels of gray matter in the spinal cord, or that will leave the cord as part of peripheral nerves. The spinal cord is the pathway for sensory impulses to the brain and motor impulses from the brain; it also mediates stretch reflexes and the defecation and urination reflexes. Thirty-one pairs of spinal nerves emerge from the spinal cord and innervate the trunk and limbs.
The column of nerve tissue that runs through the backbone from the base of the brain.
Portion of the central nervous system that originates in the brain, extends down to the lower extremity of the trunk, and is protected by the spinal column.
The part of the nervous system enclosed within the backbone.
Part of the central nervous system consisting of nerve tissue that extends from the brain down the back to just below the ribs.
Extension of the brain that carries sensory and motor commands to and from the body.
The long tube of nerve tissue, protected by bone, that extends from the brain and that carries pain and other messages.
Extended clusters of nerves situated within the vertebral canal, serving as the origin for the emergence of spinal nerves.
A nerve tissue cylinder, roughly 45 cm in length and comparable in width to a finger, extending from the brain through the central canal within the spine down to the initial lumbar vertebra. Beyond that juncture, the lowest nerve roots persist within the canal as the cauda equina. The spinal cord constitutes a significant element of the central nervous system.
Central to the spinal cord resides grey matter, harboring nerve cell bodies and various accompanying support cells. Among these nerve cells, certain ones are motor neurons that give rise to lengthy projecting fibers (known as axons), which exit the spinal cord bundled together with spinal nerves. These axons extend to glands or muscles situated in the torso and limbs. Encircling the grey matter are regions of white matter, comprised of collections of nerve cell axons running longitudinally throughout the cord.
Emerging in regular intervals on either side are the sensory and motor roots of spinal nerves. These roots merge to create the spinal nerves, establishing connections between the cord and all regions of the torso and limbs. Enveloped in cerebrospinal fluid and enclosed by three safeguarding membranes known as the meninges, the spinal cord is situated.
Within the white matter, the nerve pathways primarily function as conduits for sensory data ascending to the brain and for motor commands descending. Yet, the spinal cord also manages certain sensory input and generates motor responses independently, without requiring brain participation. Numerous reflex actions are regulated through this mechanism.
Injuries to the spinal cord can result from trauma to the spine. When nerve pathways are severed, the communication between the brain and the body regions served by the cord section below the injury gets disrupted. This disruption can lead to various forms of paralysis and/or sensory loss, typically permanent due to the inability of nerve cells and fibers within the cord to regenerate. Nevertheless, the reflexes overseen by the spinal cord generally persist. Pressure exerted on the cord, potentially due to factors like a blood clot or tumor, can similarly impact movement and sensation. In certain cases, surgical intervention may alleviate this pressure.
Infections affecting the spinal cord are infrequent but can result in severe harm. An instance of such an infection is poliomyelitis. In the case of multiple sclerosis, a degenerative condition, there occurs sporadic deterioration of the protective coverings around nerve fibers.
The neural structures and nerve pathways situated within the spinal column, running from the opening at the base of the skull to approximately the first or second lumbar vertebra.