Spinal cord

The spinal cord is part of the Central nervous system located in the spinal canal. The conventional border between oblong and spinal cord is the place of intersection of the pyramidal tract and the discharge of first cervical spine.
The spinal cord as well as the head, covered with cerebral membranes (see).
Anatomy (structure). On clinico the spinal cord is divided into 5 divisions, or parts: cervical, thoracic, lumbar, sacral, and coccygeal. The spinal cord has two thickening: cervical associated with the innervation of hands, and lumbar associated with the innervation of the feet.


Fig. 1. A cross-section of thoracic spinal cord: 1 - posterior median sulcus; 2 - posterior horn; 3 - lateral horn; 4 - front horn; 5-the Central channel; 6 - anterior median fissure; 7 - front cord; 8 - lateral cord; 9 - rear cord.

Fig. 2. The location of the spinal cord within the spinal canal (side view) and exit the spinal nerve roots: 1 - the spinal cord; 2 - a dorsal root; 3 - front root; 4 - spinal unit; 5-spinal nerve; 6 - the body of the vertebra.
the structure of the spinal cord
Fig. 3. Diagram of the locations of the spinal cord within the spinal canal (longitudinal section) and exit the spinal nerve roots: And - neck; B - chest; lumbar; G - sacral; D PC.

In the spinal cord there are gray and white matter. Gray matter - a cluster of nerve cells, which are suitable and which depart nerve fibers. The cross section gray matter has the appearance of a butterfly. In the center of the gray matter of the spinal cord is the Central canal of the spinal cord, faintly visible to the naked eye. In gray matter distinguish the front, back, and chest and side horns (Fig. 1). To sensitive cells back horns fit the processes of the cells of the spinal nodes that make up the rear roots; from motor cells of the front horns depart ventral roots of the spinal cord. Cells horns lateral belong to the autonomic nervous system (see) and provide a sympathetic innervation of internal organs, blood vessels, glands, and cell groups gray matter of the sacral - parasympathetic innervation of the pelvic organs. The processes of cells horns lateral part of the front of the roots.
The spinal roots of the spinal canal go through intervertebral holes of his vertebrae, going down on a more or less considerable distance. Especially a big way they do in the lower part of the spinal dripping, forming a pony tail (lumbar, sacral, and coccygeal roots). Front and rear roots come close to each other, forming a spinal nerve (Fig. 2). The segment of the spinal cord with two pairs of roots is called a segment of the spinal cord. Just from the spinal cord departs 31 pair of front (motor ending in muscles) and 31 pair sensitive (coming from the spinal nodes) roots. There are eight neck, twelve breast, the five lumbar, five sacral segments and one PC. The spinal cord ends at the level of I - II lumbar vertebra, so the height of the segments of the spinal cord does not meet the same vertebrae (Fig. 3).
White matter is situated on the periphery of the spinal cord, consists of nerve fibers that are collected in bunches,- is descending and ascending pathways; distinguish the front, rear and side of the spermatic cord.
The spinal cord of a newborn relatively longer than that of an adult, and comes to III of the lumbar vertebrae. Further growth of the spinal cord lags behind growth of the spine, and therefore the lower end of its moves upwards. Spinal canal newborn in relation to the spinal cord is great, but to 5-6 years the attitude of the spinal cord to the vertebral canal becomes the same as an adult. The growth of the spinal cord continues until about 20 years, the weight of the spinal cord is increased about 8 times as compared with the neonatal period.
The blood supply of the spinal cord is the anterior and posterior spinal arteries and spinal branches originating from segmental branches of the descending aorta (intercostal and lumbar arteries).

sections of the spinal cord
Fig. 1-6. The cross-sections of the spinal cord at different levels (polythematic). Fig. 1. The transition I cervical segment in the medulla. Fig. 2. I cervical segment. Fig. 3. VII cervical segment. Fig. 4. X thoracic segment. Fig. 5. III lumbar segment. Fig. 6. I sacral segment.
ascending and descending path spinal cord
Ascending (blue) and downstream (red) ways and their further communication: 1 - tractus corticospinalis ant.; 2 and 3 - tractus corticospinalis lat. (fiber after decussatio pyramidum); 4 - nucleus fasciculi gracilis (Gaulle); 5, 6 and 8 motor cranial nerve nuclei; 7 - lemniscus medlalis; 9 - tractus corticospinalis; 10 - tractus corticonuclearis; 11 - capsula interna; 12 and 19 - pyramidal cells lower divisions precentral gyrus; 13 - nucleus lentiformis; 14 - fasciculus thalamocorticalis; 15 - corpus callosum; 16 - nucleus caudatus; 17 - ventrlculus tertius; 18 - nucleus ventralls thalami; 20 - nucleus lat. thalami; 21 - crossed fiber tractus corticonuclearis; 22 - tractus nucleothalamlcus; 23 - tractus bulbothalamicus; 24 - sites of the brain stem; 25 - sensitive peripheral fiber nodes of the stem; 26 - sensitive kernel trunk; 27 - tractus bulbocerebellaris; 28 - nucleus fasciculi cuneati; 29 - fasciculus cuneatus; 30 - ganglion splnale; 31 - peripheral feel the fibers of the spinal cord; 32 - fasciculus gracilis; 33 - tractus spinothalamicus lat.; 34 - cells posterior horn of the spinal cord; 35 - tractus spinothalamicus lat., it chiasm in white soldering spinal cord.