CUTANEOUS AREAS OF THE LIMBS 



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Of the lower three areas, the lateral receives filaments from the second and third lumbar 

 nerves through the lateral femoral cutaneous (external cutaneous) branch of the lumbar plexus; 

 the middle area is supplied by the first, second, and third sacral nerves through the posterior 

 femoral cutaneous (small sciatic) nerve; and the medial area by the second and third sacral 

 nerves through the medial inferior clunial (perforating cutaneous) branch of the sacral plexua 

 (fig. 776). 



On the back of the thigh there are three areas. According to Head, the medial and lateral 

 areas are supplied by the second and third lumbar nerves, the former through the lateral 

 femoral cutaneous (external cutaneous) branch of the lumbar plexus, and the latter through 

 the anterior cutaneous branches of the femoral (internal cutaneous branch of the anterior crural) 

 nerve. The middle area receives twigs from the first, second, and third sacral nerves through 

 the posterior femoral cutaneous (small sciatic), a branch of the sacral plexus. 



The front of the thigh is supplied by the first, second, and third lumbar nerves, and, 

 according to Head, there are five cutaneous areas. The lateral area receives twigs of the 

 second and third lumbar nerves through the lateral (external) cutaneous nerves. There are 

 two medial areas, an upper and a lower. The former is supplied by the lumbo-inguinal (crural) 

 branch of the genito-femoral (genito- crural), which conveys twigs of the first and second lumbar 

 nerves; the latter receives fibres of the second and third lumbar nerves through one of the an- 



FiG. 781. — Diagram of the Cutaneous Areas of the Lower Extremity 

 (After Thorburn, modified.) 



terior (middle) cutaneous branches of the femoral (anterior crural) nerve. The small upper 

 and medial area is supplied by the first lumbar nerve through the iho-inguinal, and the lower 

 medial area receives twigs of the second and third lumbar nerves through one of the anterior 

 cutaneous branches (internal cutaneous) of the femoral (anterior crural) nerve (fig. 776). 



The front of the knee is supplied by the second, third, and fourth lumbar nerves through 

 the anterior (middle and internal) cutaneous and saphenous (long saphenous) branches of the 

 femoral (fig. 776). 



Of the skin over the region of the popliteal space, the medial portion receives fibres from the 

 second, third, and fourth lumbar nerves through the anterior (internal) cutaneous branch of 

 the femoral (anterior crural) nerve and through the superficial division of the obturator nerve; 

 the middle and lateral portion receives twigs of the first three sacral nerves through the pos- 

 terior cutaneous (small sciatic) nerve (fig. 776). 



The skin over the front and medial side of the leg is supplied by the fourth lumbar nerve 

 through the saphenous nerve, and the skin of the front and lateral side receives nerve-fibres from 

 the fifth lumbar nerves through the sural cutaneous (fibular communicating) branch of the 

 common peroneal (external popliteal) nerve. 



In the skin of the back of the leg four areas can be distinguished, a medial, two middle, 

 upper and lower, and a lateral area. The medial area is supplied by the fourth lumbar nerves 

 through an anterior cutaneous branch (internal cutaneous) of the femoral (anterior crural) 

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