19. The topography of the vagus nerve in the thoracic cavity and the anatomy and
function of the phrenic nerve
The Topography of the vagus nerve in the thoracic cavity
❖ The vagus nerve is the 10th cranial nerve (CN X).
❖ The vagus nerve has the longest course of all the cranial nerves, extending from the head to
the abdomen. Its name is derived from the Latin ‘vagary’ – meaning wandering. It is sometimes
referred to as the wandering nerve.
❖ Originates in the retro-olivary groove of the medulla oblongata and leaves the cranial cavity via
the jugular foramen
❖ Forms the lateral mixed system with the glossopharyngeal and accessory nerves
❖ Contains motor, sensory and special sensory(taste) fibres and is the only cranial nerve to reach
the abdominal cavity
❖ Gives numerous branches which provide parasympathetic and viscerosensory innervation to
the organs of the neck, thorax and abdomen, down to the Cannon-Bohm point at the left end
of the transverse colon
+
Memorix-Page 364
102
, 103
function of the phrenic nerve
The Topography of the vagus nerve in the thoracic cavity
❖ The vagus nerve is the 10th cranial nerve (CN X).
❖ The vagus nerve has the longest course of all the cranial nerves, extending from the head to
the abdomen. Its name is derived from the Latin ‘vagary’ – meaning wandering. It is sometimes
referred to as the wandering nerve.
❖ Originates in the retro-olivary groove of the medulla oblongata and leaves the cranial cavity via
the jugular foramen
❖ Forms the lateral mixed system with the glossopharyngeal and accessory nerves
❖ Contains motor, sensory and special sensory(taste) fibres and is the only cranial nerve to reach
the abdominal cavity
❖ Gives numerous branches which provide parasympathetic and viscerosensory innervation to
the organs of the neck, thorax and abdomen, down to the Cannon-Bohm point at the left end
of the transverse colon
+
Memorix-Page 364
102
, 103
