Sacral ganglia
The sacral ganglia are paravertebral ganglia of the sympathetic trunk. As the sympathetic trunk heads inferiorly down the sacrum, it turns medially. There are generally four or five sacral ganglia. In addition to gray rami communicantes, the ganglia send off sacral splanchnic nerves to join the inferior hypogastric plexus. Recurrences of genital herpes are caused by herpes simplex virus which lies dormant in the sacral ganglia between bouts of active infection. It innervates blood vessels and sweat glands in lower limbs. Near the coccyx, the right and left sympathetic trunks join to form the ganglion impar. Sacral ganglia