242 CLINICAL APPLIED ANATOMY. 



In sciatica, tender spots may be found at the sciatic notch and 

 in the middle of the posterior aspect of the thigh. 



The peroneal or external popliteal nerve passes down the outer 

 side of the popliteal space, and reaches the front of the leg by 

 winding round the outer side of neck of the fibula in the sub- 

 stance of the peroneus longus muscle, where it may be readily 

 rolled under the finger. It passes down deeply placed upon the 

 interosseous membrane to the front of the ankle, on the outer 

 side of the anterior tibial artery. On the dorsum of the foot it 

 runs forward in the first interosseous space to give sensation to 

 the contiguous sides of the great and second toes. 



In its course it supplies the following structures : two branches 

 to the knee-joint, the superior and inferior external articular, a 

 branch the communicans fibularis to join a corresponding one 

 from the internal popliteal, the communicans tibialis, to form 

 the external or short saphenous nerve, which is distributed to 

 the dorsal aspect of the outer side of the foot, and part of the 

 little toe ; by its musculo-cutaneous branch, both the peronei 

 muscles, the longus and the brevis, and the skin of the dorsum 

 of the foot on the inner side of the great toe, and the contiguous 

 sides of the second and third, third and fourth, fourth and fifth, 

 with a twig to reinforce the external saphenous on the outer side 

 of the dorsum of the little toe ; and, by the main trunk of the 

 anterior tibial nerve, the following muscles, the tibialis anticus, 

 extensor longus digitorum, extensor proprius hallucis, peroneus 

 tertius, and the extensor brevis digitorum. 



The external popliteal nerve may be severed in punctured 

 wounds of the upper part of the popliteal space or at the neck 

 of the fibula. It is also liable to injury when the biceps tendon 

 is divided subcutaneously, seeing that it lies adjacent to the inner 

 border of this structure. Paralysis of the muscles supplied by 

 this nerve is also frequently seen in cases of infantile paralysis. 



The internal popliteal nerve runs down the middle of the 

 popliteal space, and gives off branches to the following struc- 

 tures : three to the knee-joint, the superior internal articular, 

 azygos articular and inferior internal articular ; a cutaneous 



