62 LABORATORY OUTLINE OF NEUROLOGY 



(formatio reticularis) . Identify the commissures : commissura 

 ventralis alba; commissura ventralis grisea; commissura dorsalis. 

 The substantia alba (white matter) of each side is divided 

 anatomically by the emerging nerve-roots into three portions 

 named respectively funiculus dorsalis, lateralis, and ventralis 

 (Herrick ('15), Fig. 57). These funiculi are further subdivided 

 topographically into fasciculi (fasc. ventro-lateralis, etc.) which 

 are usually made up of fibers of diverse sorts. The real units of 

 spinal cord structure are the tracts, each of which is composed of 

 fibers of like connections and functions. (Neurologists often 

 use the words funiculus, fasciculus, and tract as synonyms, with 

 resulting confusion.) Your preparations present no anatomical 

 boundaries of the fasciculi and tracts. They have been deter- 

 mined by physiological experimentation and the study of degen- 

 erations following pathological lesions. 



65. Neurons of the cord. — Lay out before you the four outline 

 sketches through the spinal cord in the cervical, thoracic, lumbar, 

 and sacral regions, which have already been drawn. Now in the 

 Nissl (or toluidin blue) sections of the cord note the distribution 

 of nerve-cells in both the dorsal and ventral gray columns at each 

 of these levels and compare in detail the grouping of the cell 

 bodies in the ventral columns. Draw these groups of cells in 

 the four outline sketches of the spinal cord. The ventro-medial 

 group of neurones supplies the muscles of the back, the dorso- 

 lateral and ventro-lateral groups chiefly the muscles of the 

 limbs, and the intermedio-lateral groups the motor sympathetic 

 fibers (see Barker ('01), pp. 883-914; Bruce ('01); Cunningham 

 ('15), Fig. 467, p. 525; and Fig. 468, p. 529, also summary on p. 

 527; Curtis and Helmholz ('11); Herrick ('15), Fig. 59; Piersol 

 ('13), Figs. 895-901, pp. 1041-1046; Quain ('09), Fig. 112, p. 78; 

 Rauber-Kopsch ('07), Figs. 466^494, pp. 404-406; Sheldon ('18), 

 Chapter XXVIII. 



66. The spinal cord performs two important groups of 

 functions: (1) it contains the central mechanisms of the intrinsic 

 spinal reflexes; (2) it serves as a path of conduction between the 

 sensory and motor spinal nerves and the higher correlation cen- 

 ters of the brain. For a list of the tracts belonging to the second 

 group, see Section 101. Here attention should be directed to the 

 intrinsic reflex connections of the cord. The cell bodies of the 



