Fig. 67. Diagrammatic representation of the lower portion of the human bulb and 

 spinal cord. 



The cord is divided into its four regions: 1, Medulla cervicalis; 2, medulla dorsahs; 

 3, medulla lumbalis; 4, medulla sacralis. Within each region the spinal segments bear 

 Roman numbers. On the left side of the diagram the locality supplied by the sensory 

 (afferent) neurons is indicated by one or more words, and these latter are connected 

 with the bulb or the segments of the cord at the levels at which the nerves enter. The 

 afferent character is indicated by the arrow tip on the lines of reference. 



On the right-hand side the names of muscles or groups of muscles are given, and to 

 them are drawn reference lines which start from the segments of the cord in which the 

 cell-bodies of origin have been located. 



Within the cord itself, the designations for several reflex centers are inscribed in the 

 segment where the mechanism is localized. For example, Reflexus scapularis, Centrum 

 cilio-spinale, Reflexus epigastricus, Reflexus abdominalis, Reflexus cremastericus, Reflexus 

 patellaris, Reflexus tendo Achillis. Centrum vesicale, Centrum anale (the last two on the 

 left side of the diagram). (Donaldson, "Amer. Text-book of Physiology," from "Icones 

 Neurologicse," Strilmpell and Jakob.) 



