THE TENTH, VAGUS, OR PNEUMOGASTRIC NER VE 1011 



surface of the stomach. The right vagus sends branches to the coeliac plexus 

 (rami coeliaci), to the splenic plexus (rami lienales), and to the renal plexus (rami 

 renales). The nerve on the left side is distributed over the anterior surface of 

 the stomach and along the lesser curvature. They unite with branches of the 

 right nerve and with the sympathetic, some filaments (rami hepatica) passing 

 through the lesser omentum to the hepatic plexus. 



Applied Anatomy. It is a well-recognized fact that disease or injury of the vagus may induce 

 serious symptoms. Bruising may cause such symptoms; so may injury of the nerve by a stab, 

 a bullet, or during surgical operations. Either accidental ligation or crushing with clamp for- 

 ceps is particularly dangerous. Michaux accidentally ligated the vagus, and the patient became 

 comatose and ceased to breathe, but was restored on removing the ligature. Tillmanns, while 

 removing a cancer, accidentally caught and crushed a portion of the nerve in a clamp, and both 

 pulse and respiration ceased. The clamp was removed, the patient was restored with difficulty, 

 and the nerve was sutured. Recovery followed. It thus becomes evident that division of the 

 vagus on one side is not^ as was so long taught, a necessarily f a ta^ accident: in fact, i^s sometimes 

 undertaken deliberately in removing tumors adherent to the nerve. Division of a nerve which 

 has been long compressed is probably not so dangerous as division of a healthy nerve, as in the 

 former case the opposite vagus has probably assumed some of its colleague's duties. A number 

 of cases of deliberate division have been reported. Twenty-three cases are referred to in the 

 system of surgery by von Bergmann and Mikulicz, and in twelve the patients died, but in none 

 of the deaths was the removal of the vagus the apparent cause of the fatality. Three American 

 cases are notable: One was operated upon by Dr. W. Joseph Hearn, one by Dr. Melvin Franklin, 

 and one by Dr. J. Chalmers Da Costa. All three recovered, and not one presented any serious 

 disturbance, although each had hoarseness and weakness of voice. 



One would assume that after division of the vagus below the superior laryngeal nerve and 

 above the recurrent laryngeal nerve (the region usually attacked) there would be paralysis 

 of all the muscles of one side of the larynx, except the Cricothyroid, and widespread aberration 

 evinced by disturbances of the heart, stomach, and lungs. As a matter of fact, this has not been 

 the case. It might be and probably would be the case, were a healthy nerve divided; but the 

 surgeon who deliberately divides the nerve does so during the removal of a tumor which has long 

 made pressure. In most cases there is no change in the pulse or respiration. In some cases 

 dysphagia and pneumonia arise, but they may be due to other causes than vagus-nerve injury 

 (the formidable nature and the duration of the operation the ligation of vessels of large size 

 the age of the subject). 



Laryngeal symptoms, to a greater or less degree, are always noted. The difference in the 

 degree of the palsy is explainable when we recall Exner's statement that the muscles supplied 

 by the recurrent laryngeal also receive some innervation from the superior laryngeal. In fact, 

 Mills points out that a portion of the recurrent laryngeal has been resected without completely 

 paralyzing the muscles supposed to be supplied solely by the recurrent laryngeal. The laryngeal 

 symptoms result from unilateral laryngeal paralysis, in which there is paralysis of the muscles 

 which open the glottis. The voice may be lost or may be hoarse. Usually, after a time, this is, 

 to a great extent, compensated for by the opposite vocal cord, although the voice may always 

 remain weak, and the patient will tire easily on talking. If both vagi were to be divided death 

 would ensue. 



The laryngeal nerves are of considerable importance in considering some of the morbid con- 

 ditions of the larynx. When the peripheral terminations of the superior laryngeal nerve are 

 irritated by some foreign body passing over them, reflex spasm of the glottis is the result. When 

 the trunk of the same nerve is pressed upon by. for instance, a goitre or an aneurism of the upper* 

 part of the carotid, we have a peculiar,, dry, brassy pnn^h. When the nerve is paralyzed we 

 have anesthesia of the mucus membrane of the larynx, so that foreign bodies can readily enter 

 the cavity, and, in consequence of its supplying the Cricothyroid muscle, the vocal cords cannot 

 be made tense, and the voice is deep and hoarse. Paralysis of the superior laryngeal nerves 

 may be the result of bulbar paralysis, may be a sequel to diphtheria, when both nerves are 

 usually involved, or it may, though less commonly, be caused by the pressure of tumors or 

 aneurisms, when the paralysis is generally unilateral. Irritation of the inferior laryngeal nerves 

 produces spasm of the muscles of the larynx. When both the recurrent nerves are paralyzed 

 the vocal cords are motionless in the so-called cadaveric position that is to say, in the position 

 in which they are found in ordinary tranquil respiration neither closed as in phonation, nor 

 open as in deep inspiratory effort. When one recurrent nerve is paralyzed, the cord of the same 

 side is motionless, while the opposite cord crosses the middle line to accommodate itself to the 

 affected one; hence phonation is present, but the voice is altered and weak in timbre. The recur- 

 rent laryngeal nerves may be paralyzed in bulbar paralysis or after diphtheria, when the paralysis 

 usually affects both sides; or they may be affected by the pressure of aneurisms of the aorta, 



