1 Funiculi of spinal cord. Funiculi medullae spinalis. Three columns of white matter segmented by the posterior and anterior horns and their root fibers.

2 Anterior funiculus. Funiculus anterior. Conduction bundle located between the anterior median fissure and the anterior horn with its root fibers. A

3 Lateral funiculus. Funiculus lateralis. Conduction bundle located lateral to the gray matter and between the posterior and anterior spinal nerve roots. A

4 Posterior funiculus. Funiculus posterior. Posterior column situated between the posterior horn with its root fibers and the posterior median septum. A

5 Segments of spinal cord. Segmenta medullae spinalis. Here, the spinal cord segments are defined as regions where root fibers pass through a specific intervertebral foramen. The boundaries are not determinable in the isolated spinal cord.

6 Cervical segment. Segmenta cervicalia [1-8] = pars cervicalis. Eight cervical segments represent the seven cervical vertebrae because the root fibers of segments 1-7 exit above the vertebrae of the same number. Root fibers of the 8th cervical segment, on the other hand, exit below C7. The cervical portion of the spinal cord extends from the atlas to the middle of C7. C

7 Thoracic segment. Segmenta thoracica [1-12] = pars thoracica. The 12 segments comprising this group extend from the middle of C7 to the middle of T11. C

8 Lumbar segment. Segmental lumbaria [1-5] = pars lumbaris. Comprised of five segments; it extends from the middle of the body of T11 to the upper border of the body of L1. C

9 Sacral segment. Segmenta sacralia [1-5] = pars sacralis. These five sacral segments lie posterior to the body of L1. C

10 Coccygeal segment. Segmenta coccygea [1-3] = pars coccygea. Three quite small segments. C

11 SPINAL CORD SECTIONS. Sectiones medullae spinalis. These serve mostly as a foundation for description of the following parts.

12 Central canal. Canalis centralis. Obliterated remains of the embryonic neural tube lumen. It is usually located in the central intermediate substance (gray matter). A D

13 Gray matter. Substantia grisea. In transverse section, it is seen as an H-shaped column (columna grisea = gray column) consisting primarily of multipolar ganglion cells and enclosed by white matter. Sections of the spinal cord reveal that the "horns" (cornua) which correspond to the gray column S are characteristically different in the individual segments. A

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Essentials of Human Physiology

Essentials of Human Physiology

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