MESEN( i-:t'ii.\u>\ 



M!) 



fibres wliidi. by way of the ciliary ganglion, supply the two intrinsic muscles con- 

 cerned, vix... the ciliary muscle and the sphincter iridis. 



The nucleus of I lie oculomotor is connected with the remainder of the optic ap- 

 paratus (1) by way of the neurones of the superior quadrigeminate body with tin- 

 optic tract (retina) and the occipital part of the cerebral cortex: ('_') by way of the 

 medial longitudinal fasciculus with the nuclei of the trochlear and abducens (the 

 latter making possible the co-ordinate action of the external and internal recti for 

 the conjugate eve movements produced by these muscles), and with the nucleus of 

 the facial (associating the innervation of the levator palpebrse with that of the or- 

 bicularis oculi); (3) with the nuclei of termination of the sensory nerves, especially 

 the auditory, by way of the lemniscus and medial longitudinal fasciculus. It is 

 probably connected with the cerebellum by way of the brachia conjunctiva and red 

 nuclei. 



FIG. 611. TRANSVERSE SECTION THROUGH LEVEL OF SUPERIOR QUADIUGEMINATE BODIES. 



STK I rrv IHIXAI.K Of TIIALAMCS 



^ 



pri.nxAit fir TH 



STRATUM 7.1' 



NVCLRVS OF SUPRR10R COLI.ICUL VS ' 



x SPIPHTSIS (Pf.VKAL BOOT) 



CKXTRAI. I1KST 

 , STKATfil 



"_"- OPTIC-ACOUSTIC 

 RKFl.KX PATH 



Aur.KnrrTr.1 

 i-KRKBRI 



LATSKAI HK.fti: 



BOOT 



. 

 CMHDIHO) 



UIIIIT OF TRI- 



. i'i.t:rn 



xrci.F.rs . 



MOTOR XKkYK 



HEI>IM, l.OXrilTr- 

 DIKAL FASCII'I l.r.1 



\ IXTRRPmirxn: 



Hit FOSSA 



rnKKHRAL PKHr\ri.K 



8VB3TAKTIA NIORA 



FILA OF OCULOMOTOR KRRYK 



The eminence representing the inferior quadrigeminate body proper consists 

 of an oval mass of irrey substance. 1 he n>iclt UK oj tl r CoUKcuhtt, containing nu- 



merous nerve-cells, most of which are of small sixe. A thin superficial lamina of white 

 Mibstance, the stratum zonale, forms its outermost boundary, and fibres from the 

 lateral lemniscus enter it laterally and from below. Near the lateral margin of the 

 central <:rey sulxtance occurs the beginning of the inferior brochin/n. a bundle con- 

 taining 111 ires to and from the medial treniculale body and the tlutlamus. 



The lemniscus at this level is considered in two parts. The more lateral portion 

 of the hori/ontal arrangement assumed in the pons has here spread dorso-laterally, 

 and occupies a position in the lateral marcin of the section, and is known as the 

 lateral lemniscus, while the medial portion which remains practically horizontal 

 in the tegmentum is distinguished as the medial lemniscus. (See fin;. (i(H.) In the 

 upper portion of the lateral lemniscus occurs a small, scattered mass of grey sub- 



