In: Anatomy and Physiology
A spinal nerve is formed from the combination of dorsal root coming from the dorsal side of spinal cord and ventral root coming from the ventral side of spinal cord. The spinal nerve comes out of the vertebral canal through vertebral foramen. There are 31 pairs of spinal nerves in the body.
Dorsal root arises from the dorsal horn of spinal cord carrying sensory fibres and each dorsal root consists of a dorsal root ganglion. Ventral root arises from the ventral horn of spinal cord carrying motor fibres and the cell bodies of ventral root are called anterior horn cells.
A spinal nerve is a mixed nerve consisting of both sensory and motor components. Dorsal ramus arise from the spinal nerve which branches dorsally to supply the back of the trunk and it carries both sensory information and motor information. Ventral ramus arise ventrally from the spinal nerve supplies front of trunk and limbs and carry both sensory and motor information.
1.Dorsal root: Sensory fibres.
2.Ventral root: Motor fibres.
3.Dorsal ramus: Both sensory and motor fibres.
4.Ventral ramus: Both sensory and motor fibres.