The Lumbar, Sacral, and Pudendal plexuses are formed of the ventral divisions of the Lumbar, Sacral, and Coccygeal nerves and distribute branches to the integument and voluntary muscles of the lower abdomen, pelvis, and lower extremities. From two of the sacral nerves branches known as “Visceral” pass through the plexus to terminate in the walls of the uterus and rectum. All of the thoracic nerves and the first and second, sometimes the third and fourth, lumbar give off branches to the sympathetic ganglia, known as white rami communicantes. Direct Distribution of Cranial Nerves The distribution of the 12 pairs of cranial nerves is not so definitely to voluntary muscles and to areas from which conscious sensation is to be derived as is the case with the spinal, although the cranial nerves present many analogies with the spinal and there is abundant reason for considering them as in one series of 43 pairs. There is direct distribution of some cranial nerve fibres to secreting glands, but these fibres are probably merely derived from sympathetic trunks and carried in company with the axons of cranial origin. There is also some direct distribution of cranial nerve axons to visceral walls made of non-striated muscle, as in the case of the vagus distribution to the respiratory and alimentary tracts and that of the spinal accessory to the heart. This is a resemblance to the sympathetic. The cranial nerves carry afferent impressions from the special sense organs, except those of the sense of touch, which function is divided with the spinal nerves. Various intercommunications exist between the cranial and sympathetic divisions of the peripheral system, by means of which axons starting with one division may be finally distributed with another, or by which an axon of the sympathetic may pass to one of the sensor ganglia of the cranial system and influence its nutrition and condition, and therefore its power to act. There is a limited intermingling of spinal fibres with the lower cranial. Distribution of Sympathetic The sympathetic system directly innervates most of the nutritive or vegetative system, the alimentary tract and its accessory organs, the vascular systems, the genito-urinary system, and the ductless glands. To a limited degree it shares this control with the cerebro-spinal and to a much greater degree it brings the central axis into indirect connection with these viscera. Gray says, “The distinction of the sympathetic system from the cerebrospinal system is made merely for reasons of convenience. The two systems are intimately connected and the sympathetic is morphologically a derivative of the central axis disseminated in connection with the nutritive apparatus and establishing relationships among the vegetative organs.” Structure of Nerve Pathways