spinalis Definition

the most medial division of the sacrospinalis situated next to the spinal column and acting to extend it or any of the three muscles making up this division:

spinalis thoracis

spinalis cervicis

a muscle that arises with, inserts with, and is intimately associated with the semispinalis capitis

an inconstant muscle that arises especially from the spinous processes of the lower cervical and upper thoracic vertebrae and inserts especially into the spinous process of the axis

an upward continuation of the sacrospinalis that is situated medially to and blends with the longissimus thoracis, arises from the spinous processes of the first two lumbar and last two thoracic vertebrae, and inserts into the spinous processes of the upper thoracic vertebrae

spinal cord

the thick longitudinal cord of nervous tissue that in vertebrates extends along the back dorsal to the bodies of the vertebrae and is enclosed in the spinal canal formed by their neural arches, is continuous anteriorly with the medulla oblongata, gives off at intervals pairs of spinal nerves to the various parts of the trunk and limbs, serves not only as a pathway for nerve impulses to and from the brain but as a center for carrying out and coordinating many reflex actions independently of the brain, and is composed largely of white matter arranged in columns and tracts of longitudinal fibers about a large central core of gray matter somewhat H-shaped in cross section and pierced centrally by a small longitudinal canal continuous with the ventricles of the brain —called also medulla spinalis