Ventral ramus

Shortly after a spinal nerve exits the intervertebral foramen, it branches into the dorsal ramus, ventral ramus, and rami communicantes. Each of these latter three structures carries both sensory and motor information. Because each spinal nerve carries both sensory and motor information, spinal nerves are referred to as “mixed nerves.” The anterior ramus (ventral ramus), is the anterior root of a spinal nerve. The anterior rami supply the antero-lateral parts of the trunk and the limbs. They are generally larger than the posterior roots.

In the thoracic region they remain distinct from each other and each innervates a narrow strip of muscle and skin along the sides, chest, ribs, and abdominal wall. These are called the intercostal nerves. 

In regions other than the thoracic, anterior rami converge with each other to form networks of nerves called nerve plexuses. Within each plexus, fibers from the various anterior rami branch and become redistributed so that each nerve exiting the plexus has fibers from several different spinal nerves. One advantage to having plexuses is that damage to a single spinal nerve will not completely paralyze a limb.