[LAMENESS IN THE HIND LEG 205 



and backward, at first between the psoas major and minor, then 

 crosses the deep face of the tendon of the latter and descends 

 under cover of the sartorious over the terminal part of the 

 ilioisoas. It innervates the psoas major (magnus), psoas minor 

 ^parvus), sartorious, rectus femoris, vastus lateralis (internus). 

 Branches supply the stifle and the adductor and pectineus mus- 

 cles. 



Etiology and Occurrence. — While paralysis of the femoral 

 nerve, also known as "dropped stifle" occurs as a result of local 

 injuries and melanotic tumors in gray horses, most cases are due 

 to azoturia. So-called crural paralysis or "hip swinney" is oc- 

 casionally observed but this is not a condition wherein the nerve 

 is affected in the manner that characterizes the marked atrophy 

 of quadriceps femoris (crural) muscles in some cases of hema- 

 globinuria. This form of paralysis according to Hutyra and 

 ]Marek is due primarily to diffuse degeneration of the muscles. 



Symptomatology. — AVhen muscular atrophy is not extensive 

 no particular evidence of this condition may be manifested while 

 the subject is at rest, but where muscular waste has occurred, 

 the nature of the ailment is at once recognized. Since the fem- 

 oral nerve supplies the quadriceps femoris muscles, it follows 

 that when the psoic portion of this nerve becomes diseased, the 

 stifle loses its support, and in a unilateral involvement when the 

 subject attempts to walk on the affected member, the stifle sinks 

 down for want of support and the leg collapses unless weight is 

 caught up with the other leg. Often, following azoturia, a 

 bilateral affection is to be observed. 



Treatment, — Horses may be restrained in the standing posi- 

 tion, and in the average instance, a twitch and hood are all the 

 restraining appliances necessary. 



In cases where the disease is unilateral and atrophy is not of 

 too long standing, recovery is possible in vigorous subjects. All 

 affections, however, wherein degenerative changes involve the 

 nerve trunk, whether due to diffuse myositis or pressure from 

 malignant tumors, will not yield to treatment. 



The same general plan of treatment is indicated that is de- 

 scribed on page 7-4 in the consideration of atrophy of the 



