340 DISEASES OF THE PERIPHERAL NERVES. 



case the posterior and outer part of the thigh becomes painful ; the su- 

 perficial branch of the peroneal nerve, where the pain is in the outer 

 and anterior surface of the leg and dorsum of the foot; the sural 

 nerve (communicans tibialis), where the pain is in the outer side of 

 the ankle and foot. The sensory filaments going to the sole of the 

 foot are rarely the chief seat of pain. In the heel and back part of 

 the sole of the foot severe neuralgia, proceeding from the terminal 

 branches of the tibial nerve, is sometimes seen. Valleix gives, as the 

 most frequent points douloureux, some points behind the trochanter, 

 about three points in the thigh corresponding to the course of the 

 chief trunks, some points on the knee, one below the head of the 

 fibula, one above the outer ankle, and a few points on the ankle and 

 dorsum of the foot. 



Sciatica rarely begins with great severity ; it usually develops grad- 

 ually and slowly attains its height. The patients are never free from 

 pain, but complain of its constant presence deep in, particularly near 

 the tuberosity of the ischium, at the point where the sciatic nerve 

 passes out, and of pains in the small of the back. As the latter do 

 not come from the branches of the sciatic, but from the posterior 

 sacral nerves, Romberg calls them sympathetic. Besides these con- 

 stant pains, there are convulsive pains, particularly in the course of the 

 above-named nerves. A division into ascending and descending sciatica 

 is made, from the direction of these pains being from below upward or 

 the reverse. The pains sometimes begin spontaneously, especially after 

 going to bed, so that they not unfrequently drive the patient out of 

 bed ; sometimes they are caused by outward pressure and movements 

 of the legs. Even moderate tension of the fascia may have this effect ; 

 consequently the patient usually lies with his legs slightly flexed. 

 Greater tension of the fascia in coughing, sneezing, or straining, is often 

 accompanied by severe pain. In walking, the patient places the foot 

 of the affected side very carefully, because any quick motion or mis- 

 step usually causes severe pain. Participation of the motor filaments 

 in the disease, or a transfer of the irritation from the sensory to the 

 motor filaments through the spinal marrow, not unfrequently causes 

 cramps in the calf or other muscular contractions. Disturbances of 

 nutrition in the parts supplied by the affected nerve are not found in 

 sciatica as they are in other neuralgias. If the disease prove chronic, the 

 limb which the patient favors not unfrequently emaciates decidedly. 

 Occasionally the excitability of the sciatic is gradually impaired, and 

 we have anaesthesia and partial paralysis. 



Sciatica is a very obstinate affection. Even in favorable cases 

 several weeks usually elapse before the disease disappears, and it 

 generally subsides as gradually as it developed. In less favorable 



