Spinal Cord

Spinal Cord

Introduction

The spinal cord is a cylindrical cord with an internal cavity (spinal canal), and is held in a standing position by ligaments. Front (top) end of the spinal cord passes into the medulla oblongata, and the rear (lower) - the so-called terminal filament. Spinal nerves are the nerves from the spinal cord in almost all areas of the body, from head to lower extremities. Spinal nerves start from the junction of the anterior (motor) and posterior (sensory) roots and a trunk (up to 1 cm in diameter) going to the periphery. Thus, changes in the spine causing nerve pinching process, spine, damage to blood vessels, etc., lead to the disruption in the body, which is responsible for the damaged nerve outgrowth.

The nerves exit the spinal cord along its entire length, number one pair for each spinal segment. The bone has two enlargements, the cervical and lumbar. The cervical enlargement corresponds with the origin of the nerves that go to the upper limb, thickening cough lumbar nerves that go to the lower limb. It is protected by meningeal membranes: pia mater, arachnoid and dura mater and the cerebrospinal fluid. From the region of the second lumbar vertebra, where the bone ends, to the coccyx, descends a thin filament called "filum terminale" and the roots of the sacral and lumbar nerves, forming a bundle of fibers called the "tail horse.”

External Anatomy

The spinal cord nerve tissue is considered the largest in the human body and can reach your neurons up to a meter long. Weighing approximately 30 grams, fully developed spinal cord reaches the length of 45 cm for men and 43 cm in women within the spinal canal called hueso intravertebral from the foramen magnum, in the middle of arquial atlas until the first or second lumbar vertebra. Indeed, in the newborn spinal reaches L3, two vertebrae below and is embryonically to the base of the coccyx. It is cylindrical in the upper cervical and lumbar segments, while the ball with a diameter greater than the front transverse to the superior cervical and thoracic segments. The bone is asymmetric in nearly 75% of human beings, with the right side the greatest in 75% of asymmetries (Jill 2003, 132).

Anatomy Transverse

In cross-section, the bone is formed along its length and its divisions a gray area, gray matter in the form of "H" or butterfly in the center and a peripheral white matter, unlike in the brain.

Their halves are divided in a sagittal by two processes: in the dorsal, posterior median septum are long and narrow, and ventrally the anterior median fissure, which is wider and shorter. Longitudinally divided into 31 segments, one for each pair of ribs, well, the spinal nerves are placed in eight cervical, twelve thoracic, five lumbar, five sacral and one coccygeal. Each segment has two pairs of roots (dorsal and ventral) located symmetrically in the dorsal and ventral.

The gray matter is mainly composed of neurons and supporting cells (neuroglia). It has two poles and two poles above gray ...