Z8600021: ==Fig. 675. A spinal nerve with its anterior and posterior roots== Roots of the Spinal Nerves As already stated, each spinal nerve possesses two roots, an anterior and a posterior, which are attached to the surface of the medulla spinalis opposite the c

2012-10-17T03:10:16Z

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==Fig. 675. A spinal nerve with its anterior and posterior roots==

Roots of the Spinal Nerves

As already stated, each spinal nerve possesses two roots, an anterior and a posterior, which are attached to the surface of the medulla spinalis opposite the corresponding column of gray substance (Fig. 675); their fibers become medullated about the fifth month of fetal life.

===Anterior Nerve Root===

(radix anterior) Consists of efferent fibers, which are the axons of the nerve cells in the ventral part of the anterior and lateral columns. A short distance from their origins, these axons are invested by medullary sheaths and, passing forward, emerge in two or three irregular rows over an area which measures about 3 mm. in width.

===Posterior Root===

(radix posterior) Comprises some six or eight fasciculi, attached in linear series along the postero-lateral sulcus. It consists of afferent fibers which arise from the nerve cells in a spinal ganglion. Each ganglion cell gives off a single fiber which divides in a T-shaped manner into two processes, medial and lateral. The lateral processes extend to the sensory end-organs of the skin, muscles, tendons, joints, etc. (somatic receptors), and to the sensory end-organs of the viscera (visceral receptors). The medial processes of the ganglion cells grow into the medulla spinalis as the posterior roots of the spinal nerves.

{{Gray Anatomy}}

[[Category:Spinal Cord]]

File:Gray0675.jpg - Revision history

Z8600021: ==Fig. 675. A spinal nerve with its anterior and posterior roots== Roots of the Spinal Nerves As already stated, each spinal nerve possesses two roots, an anterior and a posterior, which are attached to the surface of the medulla spinalis opposite the c