From Wikipedia, the free encyclopedia

Dorsal root ganglion
This is a dorsal root ganglion (DRG) from a chicken embryo (around stage of day 7) after incubation overnight in NGF growth medium stained with anti-neurofilament antibody. Axons growing out of the ganglion are visible.
A spinal nerve with its anterior and posterior roots. The dorsal root ganglion is the "spinal ganglion", following the posterior/dorsal root.
Latin	g. sensorium nervi spinalis
Gray's	subject #185 750
Precursor	neural crest
MeSH	Spinal+Ganglia
Dorlands/Elsevier	g_02/12384883

In anatomy and neurology, the dorsal root ganglion (or spinal ganglion) is a nodule on a dorsal root that contains cell bodies of neurons in afferent spinal nerves.

Contents 1 Unique unipolar structure 2 Distal section 3 Location 4 Embryology 5 Nociception 6 References 7 See also 8 Additional images 9 External links

The axons of dorsal root ganglion neurons are known as afferents. In the peripheral nervous system, affarents refer to the axons that relay sensory information into the central nervous system and spinal cord. These neurons are of the pseudo-unipolar type, meaning they have an axon with two branches that act as a single axon, often referred to as a distal process and a proximal process.

Unlike the majority of neurons found in the central nervous system, an action potential in dorsal root ganglion neuron may initiate in the distal process in the periphery, bypass the cell body, and continue to propagate along the proximal process until reaching the synaptic terminal in the dorsal horn of the spinal cord.

The distal section of the axon may either be a bare nerve ending or encapsulated by a structure that helps relay specific information to nerve. For example, a Meissner's corpuscle or Pacinian corpuscle may encapsulate the rendering the distal process sensitive to mechanical stimulation, such as stroking or vibration, respectively. ^[1]

The dorsal root ganglia lie along the vertebral columna by the spine.

The dorsal root ganglia develops in the embryo from neural crest cells.

G protein-coupled receptor on the DRG have been associated with nociception.^[2]

1. ^ Kandel ER, Schwartz JH, Jessell TM. Principles of Neural Science, 4th ed., p.431-433. McGraw-Hill, New York (2000). ISBN 0-8385-7701-6
2. ^ Huang CW, Tzeng JN, Chen YJ, Tsai WF, Chen CC, Sun WH (2007). "Nociceptors of dorsal root ganglion express proton-sensing G-protein-coupled receptors". Mol. Cell. Neurosci. 36 (2): 195–210. doi:10.1016/j.mcn.2007.06.010. PMID 17720533. 

• Ventral root

Medulla spinalis

The formation of the spinal nerve from the dorsal and ventral roots |

Scheme showing structure of a typical spinal nerve.

• SUNY Figs 02:04-09
• Histology at BU 04401loa
• Photo of model at Ohio State University
• Diagram at webanatomy.net
• Photo at uwlax.edu

v • d • e Anatomy of torso (primarily): the spinal cord
Spinal nerve	Dorsal (Root, Ganglion, Ramus) • Ventral (Root, Ramus) • Sympathetic trunk • rami communicantes (Gray, White)
Gray matter/Rexed laminae	Posterior horn (Column of Clarke, Substantia gelatinosa of Rolando, Nucleus proprius) • Lateral horn • Anterior horn • Central canal/Substantia gelatinosa centralis
White matter: somatic/ascending (blue)	Posterior/PCML: Gracilis • Cuneatus Lateral: Spinocerebellar (Dorsal, Ventral) • Spinothalamic (Lateral, Anterior) • Spinotectal • Posterolateral (Lissauer)
White matter: motor/descending (red)	Lateral: Corticospinal (Lateral) • Ep (Rubrospinal, Olivospinal) Anterior: Corticospinal (Anterior) • Ep (Vestibulospinal, Tectospinal, Reticulospinal)
Layers	Epidural space • Dura mater • Subdural space • Arachnoid mater • Subarachnoid space • Pia mater
Other structures	Denticulate ligaments • Conus medullaris • Cauda equina • Filum terminale • Cervical enlargement • Lumbar enlargement • Anterior median fissure