THE SMALL SCIATIC [NERVE 



613 



Small Sciatic ITerve. 



The small sciatic nerve (nervus ischiadicus minor) is chiefly a 

 cutaneous nerve, supplying the integument of the lower part of 

 the buttock, the back of the thigh, and upper part of the calf 

 of the leg ; it furnishes also branches to one muscle — the gluteus 

 niaximus. 



This nerve is formed by the union of two or more nervous cords, 

 derived from the lower and back part of the sacral plexus. Arising 

 below the pyriform muscle, it descends beneath the gluteus maximus, 

 and at the lower border of that muscle comes into contact with the 

 fascia lata. Continuing its course downwards along the back of the 

 limb, it perforates the fascia a little below the knee. 



Fig. 374. — Deep Nerves in the Fig. 374. 



Gluteal and Inferior Pudendal 



Regions (after Hii-scMeld and Le- 

 veille). 5: 



«, back part of tlie great trochanter ; 

 h, tensor vaginre femoris muscle ; c, 

 tendon of tlie obturator interuus muscle 

 near its insertion ; d, upx^er part of tlie 

 vastus externus ; c, coccj^ ; /, gracilis 

 muscle ; between / and d, the adductor 

 magnus, semiteudinosus, and biceps 

 muscles ; * placed at the meeting of the 

 crura penis above the ui'ethra ; 1, 

 placed upon the ilium close above the 

 sacro-sciatic notch, marks the superior 

 gluteal nerve, and on the divided parts 

 of the gluteus medius muscle, the supe- 

 rior branch of the nerve ; 1', on the 

 surface of the gluteus minimus muscle, 

 the inferior branch of the nerve ; 1 " , 

 Ijranch of the nerve to the tensor vagina; 

 femoris ; 2, sacral plexus and great 

 sciatic nerve ; 2', mixscular twig from 

 the plexus to the pyriformis ; 2", mus- 

 cular branches to the gemellus superior 

 and obturator internus ; 3, lesser sciatic 

 nerve ; 3', j)laced on the upper and * 



lower parts of the divided gluteus 



maximus, the inferior gluteal muscular branches of the lesser sciatic nerve; 3", the 

 cutaneous branches of the same nerve winding round the lower border of the gluteus 

 maximus ; 4, the continuation of the lesser sciatic nerve as posterior cutaneous nerve of 

 the thigh ; 4', inferior pudendal branch of the lesser sciatic ; 5, placed on the lower part 

 of the sacral plexus, points to the origin of the pudic nerve ; 6, its perineal division ■with 

 its muscidar branches ; 6', anterior or superior superficial ijei-iueal branch ; 6", ijosterior 

 or inferior superficial perineal ; -i- + , distribution of these nerves and the inferior puden- 

 dal on the scrotum ; 7, dorsal neiTe of the penis. 



Branches. — ^4. The inferior gluteal branches, given off under the gluteus 

 maximus. supply the lower part of that muscle. — A distinct gluteal branch com- 

 monly proceeds from the sacral plexus to the upper part of the muscle. 



B. The cutaneous hranches of the nerve principally emerge from beneath the 

 lower border of the gluteus maximus, arranged in an external and an internal 

 set. Others appear lower cIomti. 



a.' Tlie internal are mostly distributed to the skin of the inner side of the 

 thigh at the upper part. One branch, however, which is much larger than the 

 rest, is distinguished as the iaferior pudendal. 



