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NEUROLOGY 



The Lumbar Nerves (Nn. Lumbales). 



The medial branches of the posterior divisions of the lumbar nerves run close to the 

 articular processes of the vertebrae and end in the Multifidus. 



The lateral branches supply the Sacrospinalis. The upper three give off cutaneous 

 nerves which pierce the aponeurosis of the Latissimus dorsi at the lateral border of 

 the Sacrospinalis and descend across the posterior part of the iliac crest to the skin 

 of the buttock (Fig. 801), some of their twigs running as far as the level of the 

 greater trochanter. 



OF LOWER 'SACRAL NERVES 



FIG. 803. The- posterior divisions of the sacral nerves. 



The Sacral Nerves (Nn. Sacrales). 



The posterior divisions of the sacral nerves (rami posteriores) (Fig. 803) are 

 small, and dimmish in size from above downward; they emerge, except the last, 

 through the posterior sacral foramina. The upper three are covered at their points 

 of exit by the Multifidus, and divide into medial and lateral branches. 



The medial branches are small, and end in the Multifidus. 



The lateral branches join with one another and with the lateral branches of the 

 posterior divisions of the last lumbar and fourth sacral to form loops on the dorsal 

 surface of the sacrum. From these loops branches run to the dorsal surface of the 

 sacrotuberous ligament and form a second series of loops under the Glutseus maxi- 

 mus. From this second series cutaneous branches, two or three in number, pierce 

 the Glutaeus maximus along a line drawn from the posterior superior iliac spine to 

 the tip of the coccyx; they supply the skin over the posterior part of the buttock. 



The posterior divisions of the lower two sacral nerves are small and lie below the 

 Multifidus. They do not divide into medial and lateral branches, but unite with 

 each other and with the posterior division of the coccygeal nerve to form loops on 

 the back of the sacrum ; filaments from these loops supply the skin over the coccyx. 



