THE LUMBO-SACRAL PLEXUS. 



773 



arrives outside the pelvis, where it nevertheless remains deeply concealed by 

 the muscular masses on the internal aspect of the thigh. Its terminal rami- 

 fications are expended in the obturator externus, the adductors of the thigh, 

 the pectineus, and the short adductor of the leg. -Ti.e branch destined to 

 the latter muscle is the longest ; it leaves the space between the pectineus 

 and the small adductor of the thigh, and descends backwards on the internal 

 lace of the nmscle to \vhich it is distributed. 



4. Small Sciatic or Anterior and Posterior Gluteal Nerves. 



The small sciatic of the Horse is composed of several cords that issue 

 from the pelvis by the upper part of the great ischiatic notch, and which have 



POSTERIOR PORTION OF THE LUMBO-SACRAL PLEXUS. 



1, Conjoining fasciculi of the three first sacral nerves ; 2, 3, 4, 5, Anterior gluteal 

 nerves ; 6, 6', 8, Posterior gluteal nerves ; 7, 9, Branches which traverse the 

 great sciatic ligament, and communicate between the posterior gluteal branches 

 and the divisions of the internal pudic nerve; 10, 11, 12, 13, Great sciatic nerve 

 and its crural branches ; 14, Small femoro-popliteal nerve ; 15 Its cutaneous or 

 peroueal-cutaneous branch. 



been for a long time described as the anterior and posterior gluteal 

 nerves. 



The anterior gluteal or ilio-muscular nerves (Fig. 356, 2, 3, 4, 5) are four 

 or five in number, and arise either separately or in groups from the posterior 

 portion of the lumbo-sacral plexus. They appear to be more particularly 

 furnished by the two first sacral branches. All leave the pelvic cavity by 

 the great sciatic opening, along with the anterior gluteal vessels. The 

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