1364 



A MANUAL OF ANATOMY 



from the tuberculum acusticum of the opposite side. Certain of 

 the fibres of the trapezium terminate in the superior olivary nucleus, 

 but the majority cross the median plane, where they decussate 

 with those of the opposite side. Having crossed to the opposite 

 side, they become longitudinal, and form a well-marked ascending 

 tract in the dorsal part of the pons Varolii, called the lateral fillet, 

 which lies on the outer side of the main or mesial fillet. 



Fig. 571. — Vertical Transverse Section through the Upper Part of 

 THE Pons Varolii (from L. Testut's 'Anatomie Humaine,' after 

 Stilling). 



1. Fourth Ventricle 



2. Valve of Vieussens 



3. Superior Root of Fifth Nerve 



4 Nerve-cells which accompany this Root 



5. Posterior Lonptudinal Bundle 



6. Formatio Reticul.iris 



7. Lateral Fissure of Isthmus 



8. Section of Superior Cerebellar Peduncle 

 9, 9 . Mesial and Lateral Portions of the 

 Fillet 



10, 10. Transverse Fibres of the Pons 



11, II. Longitudinal Fibres of the Pons 

 12. Raph<i 



V. Fifth Nerve 



Dorsal or Tegmental Part ol the Pons. — ^This portion is divided 

 into two symmetrical halves by a median raph^, which is continuous 

 with that of the upper or open part of the medulla oblongata. It 

 consists of formatio reticularis, which is continued upwards from 

 the formatio reticularis of the bulb. The formatio reticularis of 

 the dorsal part of the pons contains certain tracts of nerve-fibres 

 and nuclei, with which important nerves are connected. These 



