Name: spinal cord structure and dermatomes
Uploaded: 2025-10-23T11:49:14.000Z
Duration: 1 min 54 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.25

The Spinal Cord

- [Instructrice] La moelle épinière est un cylindre épaisde tissu nerveux qui comprendune partie du système nerveux central,transmettant des informations sensorielles afférentesde la périphérie au cerveauet des informations motrices efférentesdu cerveau à la périphérie. 
En coupe transversale,la matière grise à l'intérieur de la moelle épinièreest en forme de papillon. 
La corne ventrale de la matière grisecontient les neurones moteurs. 
Il est entouré de matière blanche avec des groupes d'axonesdes voies à la fois ascendantes et descendantes. 
Au centre se trouve un canal centralcontenant le liquide céphalo-rachidienqui nourrit le tissu nerveux. 
Le cordon lui-même est entouré de membranes,les méninges rachidiennes, qui incluent les pachyméninges. 
Connectée au tronc cérébral,la moelle épinière traverse le trou occipitalet la série d'os de la colonne vertébralejusqu'à la terminaison du niveau lombaire L1, deux,et forme un long faisceau de nerfsappelé queue-de-cheval. 
Elle est subdivisée en niveaux ou régions,déterminés par la position des vertèbres,avec des nerfs spinaux appariés. 
Par exemple, la colonne cervicale, région C2 à C7,correspond aux nerfs innervant le cou,les épaules, les bras et les mains. 
Dans chaque vertèbre, des paires de racines nerveusessortent par le trou vertébral en branches distinctes. 
La racine du nerf ventral aiguille les musclesdans le contrôle du mouvement,tandis que la racine du nerf dorsal innerve la peaudans la transmission de la sensation. 
Chaque zone de la peau innervée parun nerf spinal spécifique est appelée dermatomeet représentée par les cartes de dermatome. 
Ces cartes permettent aux cliniciens d'identifierl'origine d'une douleur ou affection cutanée quelconque.

Hochman, Shawn. « Moelle épinière ». Current Biology 17, n° 22 (20 novembre 2007) : R950-55. [<a href="https://doi.org/10.1016/j.cub.2007.10.014 » target="__blank">Source</a>]

Ahuja, Christopher S., Satoshi Nori, Lindsay Tetreault, Jefferson Wilson, Brian Kwon, James Harrop, David Choi et Michael G. Fehlings. « Lésion traumatique de la moelle épinière – Réparation et régénération ». Neurosurgery 80, n° 3S (1er mars 2017) : S9-22. [<a href="https://doi.org/10.1093/neuros/nyw080 » target="__blank">Source</a>]

la moelle épinière

La moelle spinale est la principale région nerveuse du système nerveux central du corps, communiquant des informations sensorielles afférentes de la périphérie au cerveau et des informations motrices efférentes du cerveau au corps. La moelle spinale humaine s’étend de l’orifice à la base du crâne, ou foramen magnum, au niveau de la première ou deuxième vertèbre lombaire.
 
 <h4>La vue transversale</h4>
 
 La moelle spinale est cylindrique et contient à la fois de la matière blanche et grise. Au centre se trouve le canal central, qui est le vestige du lumen du tube neural primitif et fait partie du système interne des cavités du liquide céphalo-rachidien. En coupe transversale, la matière grise entourant le canal central apparaît en forme de papillon.
 
 Les ailes du papillon sont divisées en cornes dorsales et ventrales. La corne dorsale contient des noyaux sensoriels qui relayent l’information sensorielle, et la corne ventrale contient des neurones moteurs donnant naissance aux axones qui innervent le muscle squelettique.
 
 La matière blanche entoure la matière grise et contient un grand nombre de fibres myélinisées. La matière blanche est disposée en faisceaux longitudinaux appelés colonnes dorsales, latérales et ventrales. Trois membranes entourent la moelle spinale : la pie-mère adhère étroitement à la surface de la moelle spinale, suivie par l’arachnoïde et la dure-mère, la gaine la plus externe.
 
 <h4>L’organisation</h4>
 
 La moelle spinale est divisée en quatre régions différentes et elle est organisée par segments. Il y a 31 paires de nerfs sortant de la moelle : huit cervicales, 12 thoraciques, cinq lombaires, cinq sacrées, et une coccygienne.
 
 <h4>Les dermatomes</h4>
 
 Chaque segment de la moelle spinale innerve une région différente du corps et il est représenté sur la peau comme un dermatome. Un dermatome est une zone de la peau desservie par un nerf périphérique provenant d’un seul ganglion spinal. Cliniquement, les cartes de dermatomes sont utiles pour déterminer le niveau des lésions de moelle spinale et pour localiser les lésions des racines de nerfs périphériques. Toutefois, il faut tenir compte du fait qu’il existe des variations considérables et des chevauchements de dermatomes des segments spinaux adjacents. Bien qu’il existe 31 paires de nerfs spinaux, il n’y a que 30 dermatomes, parce que C1 n’a généralement pas de racine spinale et donc le premier dermatome correspond à C2.

La moelle épinière

La moelle épinière est le principal tractus nerveux du corps du système nerveux central, communiquant des informations sensorielles afférentes de la périphérie au ...

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Biology

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KEY TERMS AND CONCEPTS

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spinal cord structure and dermatomes

The spinal cord is the main nerve pathway of the central nervous system. It carries sensory signals from the body to the brain and motor signals from the brain to the body. It begins at the foramen magnum, the opening at the base of the skull, and extends to the level of the first or second lumbar vertebra.

In cross-section, the spinal cord is cylindrical and contains both gray matter and white matter. The central canal lies in the middle and is a remnant of the lumen of the primitive neural tube. It is part of the internal system of cerebrospinal fluid cavities. The gray matter around it has a butterfly shape. Its dorsal horns contain sensory nuclei that relay sensory input, and its ventral horns contain motor neurons that send axons to skeletal muscle.

White matter surrounds the gray matter and contains many myelinated fibers. It is organized into longitudinal bundles called the dorsal, lateral, and ventral columns. Three membranes protect the spinal cord. The pia mater lies directly on its surface, the arachnoid lies outside the pia, and the dura mater forms the tough outer sheath.

The spinal cord is divided into four regions and is organized in segments. There are 31 pairs of spinal nerves: eight cervical, 12 thoracic, five lumbar, five sacral, and one coccygeal. Each segment connects to a specific part of the body.

These body maps are called dermatomes. A dermatome is an area of skin supplied by a peripheral nerve from a single dorsal root ganglion. Dermatome maps help locate spinal cord lesions and peripheral nerve root lesions. The pattern is not exact, because adjacent dermatomes can overlap and vary. Although there are 31 pairs of spinal nerves, there are only 30 dermatomes, since C1 usually has no spinal root and the first dermatome is C2.

Spinal Cord Structure and Dermatomes

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the spinal cord

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key terms and concepts

Explore spinal cord structure, gray and white matter, spinal nerve regions, and dermatomes with a clear high school biology focus.

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D. Most multicellular organisms are composed of organ systems whose structures reflect their particular function.

Spinal Cord Structure and Dermatomes

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