Which of the following statement(s) regarding the vagus nerves is/are true?

a. The right and left vagus nerves derive from a nerve plexus inferior to the tracheal bifurcation

c. The anterior vagus supplies a hepatic division which passes to the right in the lesser omentum

d. Approximately 90% of vagal fibers are afferent, transmitting information from the gastrointestinal tract to the central nervous system

The left and right vagus nerves are formed from a periesophageal nerve plexus between the tracheal bifurcation and the diaphragm. As they pass through the esophageal hiatus, the anterior vagus is closely applied to the esophagus; the posterior vagus lies intermediate in position between the esophagus and the aorta. The anterior vagus supplies the hepatic division which provides parasympathetic innervation to the liver and biliary tract. The hepatic division is usually easily seen in the thin gastrohepatic omentum and is constant in location. The hepatic division is a useful anatomic landmark in vagotomy procedures. The posterior vagus nerve supplies fibers to the celiac division. After giving off hepatic and celiac divisions, both anterior and posterior vagus nerves supply branches to the gastric wall. Surprisingly, only 10% of vagal fibers are efferent, secretomotor fibers; almost 90% are afferent. Sensations of gastric pain are carried in sympathetic fibers, and vagotomy does not alter perception of painful gastric conditions or stimuli.