SPINAL ACCESSORY NERVE. 557 



ficiently familiar. When facial palsy affects one side and is complete, the 

 angle of the mouth is drawn to the opposite side, the eye upon the affected 

 side is widely and permanently opened, even during sleep, and the face has 

 upon that side a peculiarly expressionless appearance. When a patient 

 affected in this way smiles or attempts to grimace, the distortion is much 

 increased. The lips are paralyzed upon one side, which sometimes causes a 

 flow of saliva from the corner of the mouth. In the lower animals that use 

 the lips in prehension, paralysis of these parts interferes considerably with 

 the taking of food. The flaccidity of the paralyzed lips and cheek in the 

 human subject sometimes causes a puffing movement with each act of expi- 

 ration, as if the patient were smoking a pipe. 



The buccinator is not supplied by filaments from the nerve of mas- 

 tication but is animated solely by the facial. Paralysis of this muscle inter- 

 feres materially with mastication, from a tendency to accumulation of the 

 food between the teeth and the cheek. Patients complain of this difficulty, 

 and they sometimes keep the food between the teeth by pressure with the 

 hand. In the rare instances in which both facial nerves are paralyzed, there 

 is very great difficulty in mastication, from the cause just mentioned. 



The action of the external branches of the facial is thus sufficiently sim- 

 ple ; and it is only as its deep branches affect the sense of taste, the move- 

 ments of deglutition, etc., that it is difficult to ascertain their exact office. 

 As this is the nerve of expression of the face, it is in the human subject that 

 the phenomena attending its paralysis are most prominent. When both 

 sides are affected, the aspect is remarkable, the face being absolutely expres- 

 sionless and looking as if it were covered with a mask. 



SPIRAL ACCESSORY (ELEVENTH NERVE). 



The spinal accessory nerve, from the great extent of its origin, its impor- 

 tant anastomoses with other nerves and its peculiar course and distribution, 

 has long engaged the attention of anatomists and physiologists, who have 

 advanced many theories with regard to its office. Its physiological history, 

 however, begins with comparatively recent experiments, which alone have 

 given a positive knowledge of its properties and uses. 



Physiological Anatomy The origin of this nerve is very extensive. A 

 certain portion arises from the lower half of the medulla oblongata, and the 

 rest takes its origin below, from the upper two-thirds of the cervical portion 

 of the spinal cord. That portion of the root which arises from the medulla 

 oblongata is called the bulbar portion, the roots from the cord constituting 

 the spinal portion. Inasmuch as there is a marked difference between the 

 uses of these two portions, the anatomical distinction just mentioned is im- 

 portant. 



The superior roots arise by four or five filaments, from the lower half of 

 the medulla oblongata, below the origin of the pneumogastrics. These fila- 

 ments of origin pass to a gray nucleus in the medulla, below the origin of 

 the pneumogastric. 



The spinal portion of the nerve arises from the upper part of the spinal 

 37 



