Tracts of the spinal cord (cross section)

Tracts of the spinal cord (cross section)(Englisch version, 3D)Schematic cross section of the spinal cord in the upper cervical area.Inside the spinal cord there are nerve fibres and perikaria of the afferent and efferend nerve cells of the CNS. It is constructed segmentally. From cranially to caudally:

Cervical cord (Pars cervicalis medullae spinalis): Segments C1 to C8

Thoracic cord (Pars thoracalis medullae spinalis): Segments Th1 to Th12

Lumbar cord (Pars lumbalis medullae spinalis): Segments L1 to L5

Sacral cord (Pars sacralis medullae spinalis): Segments S1 to S5

The coccygeal cord (Pars coccygis medullae spinalis) is only rudimentary in humans and is represented by one segment (Co1).

In the area of the cervical cord and the lumbar cord the spinal cord is visibly thicker, which is caused by a higher number of nerve cells (of the sympathic nervous system).On the ventral side if the spinal cord there is a longitudinal fissure, the anterior median fissure. On the dorsal side there is the posterior median sulcus. The imaginary connecting line between these structures marks the symmetry plane of the spinal cord. On both sides three areas of white matter can be differentiated.

The anterior area which is next to the anterior median fissure, which cannot be clearly divided from the

lateral area and is therefore often conflated into the anterolateral area, and the

posterior area

Between posterior and lateral area the posterior roots leave the spinal cord from the posterior lateal sulcus.The anterior roots leave the spinal cord between medial and anterior area from the anterior lateral sulcus.Picture: Selket und Mikael Häggström