GLUT^EAL REGION 



219 



a bed in which the cutaneous nerves ramify before they enter 

 the skin. In this region 

 the cutaneous nerves are 

 very numerous, and they 

 are derived from a great 

 variety of sources. Some 

 proceed from the posterior 

 branches of the spinal 

 nerves, whilst others are 

 given off from the anterior 

 branches of the spinal nerves. 

 From the posterior 

 branches there are usually 

 six three from the sacral 

 nerves, and three from 

 the lumbar nerves. The 

 three sacral nerves reach 

 the surface by piercing 

 the glutaeus maximus 

 muscle close to its origin 

 from the sacrum and coc- 

 cyx. They are usually 

 of small size and pierce 

 the muscle in a line drawn 

 from the posterior superior 

 iliac spine to the tip of the 

 coccyx. The largest is 

 found opposite the lowest 

 piece of the sacrum, the 

 highest about an inch 

 above this, and the lowest 

 about the same distance 

 below it. 



Lumbar nerves 



Cutaneous branches 



of the 1 2th thoracic 



and ilio-hypogastric 



nerve 



Sacral nerves 



Perforating 

 cutaneous 



Branches from N. 



cutaneus femoris 



posterior 



N. cutaneus femoris 

 lateralis | 



Long perineal' 



N. cutaneus femoris 

 posterior 



Medial cutaneous 

 (O.T. internal)' 



N. cutaneus femoris 

 lateralis 



Medial cutaneous 

 (O.T. internal)" 



Nervus Anastomoticus 

 peronaeus 



N. cutaneus femor 

 posterior 



Nervus cutaneus sura; 

 medialis (O.T. ram us - 

 communicans tibialis) 



Nervus suralis 

 (O.T. short saphenous) 



Owing to the coarseness of 

 the muscular fasciculi of the 

 glutseus maximus between which 

 they appear, they are somewhat 

 difficult to find. In looking for 

 them, it is best to cut right down 

 through both superficial and 

 deep fasciae, so as to secure them 

 as they emerge from the muscle. 



Ramus calcaneus medialis 



FIG. 83. Cutaneous Nerves on the 

 posterior aspect of the Lower Extremity. 



The three lumbar nerves are easily found. They cross 



