NJERVES IN THE MEMBBANA TYMPANT OF MAN 105 



sel and nerve approach the manubrium the artery passes under 

 the nerve and in the rest of its course hes adjacent to it, but nearer, 

 to the manubrium. As the nerve bundle passes downward it 

 frequently gives off branches which pass outwards towards the 

 limbus, on the anterior side passing over and external to the manu- 

 brium. At a point inferior to the middle of the manubrium the. 

 nerve bundle spreads out and while at first the majority of its 

 fibers still have a downward direction, the general tendency and 

 ultimate course is towards the limbus. A considerable number pass 

 over the manubrium; of these some may be traced to the anterior 

 limbus, but the greater number break up and get lost in the 

 plexus over the manubrium or anterior to it. At the apex of the 

 manubrium the fibers radiate out ; some curving round the apex,: 

 join fibres which have crossed the manubrium, and pass out to the. 

 anterior limbus. In short, while the main nerve is passing down- 

 wards along the manubrium it is constantly sending off on each 

 side branches which have a general direction towards the pe- 

 riphery. A smaller but well marked nerve bundle which has 

 branched off from the main trunk in the external auditory meatus 

 enters the membrana flaccida slightly superior to the main bundle. 

 It is directed towards the anterior superior segment, and passes 

 sometimes directly over the processus lateralis, but always within 

 a short distance of it. 



In addition to these, numerous smaller bundles pass in from the 

 external auditory meatus not only over the membrana flaccida, 

 but all around the periphery. At the limbus these fibers can be 

 noted at short irregular intervals entering under the epidermal 

 prolongation. While the general direction of their main stem is 

 towards the center of the membrana tensa, both external and in- 

 ternal to the limbus, branches are given off which form a well 

 marked plexus, the zonular plexus, from which fibers radiate 

 toward the center. 



The radiating fibers whether coming from the nerves entering 

 at the membrana flaccida or from the limbus give off numerous 

 twigs and gradually get smaller. These twigs, in the main non^ 

 medul'ated or with a very faint medullary sheath, after usually 

 a long course during which they repeatedly divide, pass into : 



