MUSCLES OF THE POSTERIOS. LIMBS. 281 



founded, anteriorly, witli the posterior border of the muscular portion of its 

 terminal tendon; at its inner and superior border it degenerates into 

 cellular tissue. 



Attachments.— Ihis muscle has its fixed insertion : 1, On the internal 

 aspect of the gluteal aponeurosis, by the superior extremity of it's muscular 

 fasciculi ; ^ 2, On the postero-external angle of the iscluum, and the isohiatic 

 ligament, by the internal border of its aponeurotic-Sfirtion. It has its 

 movable insertion, by means of its terminal tendon,'on^e small external or 

 third trochanter of the femur. 



Belations. — Outwardly, with the gluteal aponeurosis and the anterior 

 portion of the long vastus. Inwardly, with the middle gluteus ; by its 

 anterior border, with the fascia lata, to which it is closely united. 



Aetion._ — This muscle has been jvilj considered by Lafosse a^ an a,bductor 

 of the thigh. Bourgelat wrongly regarded it as an extensor, and Girard 

 and Eigot have repeated his error. Lecoq has proved that it rather produces 

 flexibn than extension. (Leyh states that it is an extensor and a rotator of 

 the thigh outwards.) 



2. Middle Gluteus. (Fig. 129, 1.) 



Synonyms. — Hio-troehanterius magnns — Girard. »£Huteus maximus — Bourgelat, 

 Lafmse, Biio^tc. Gluteus mediufe offMan. {Olutem maximus — Percivall. Superior 

 portion of t'lie great ilio-trochanterius — Leyh.) 



Volume — Situaiiop.: — This muscle, the largest of the glutei, presents a 

 considerable voltMne, and is applied against the iliac fossa, the sacro-ischiatic 

 ligament, and the ilio-spinalis muscle. 



Fr i and Structure. — It is elongated from before to behind, wide and 

 very thick in its middle^ prolonged forward by a ttiin point, and terminated 

 behind by three branches of insertion — two tendinous and one muscular. 

 The muscular ' fasciculi entering into its composition are generally very 

 thick and more or less long; all converge towards the posterior insertions 

 of the muscle. 



Attachments. — 1, By the superior or anterior extremities 'Of the muscular 

 fasciculi, on the internal aspect of the gluteal aponeurosis, the aponeurosis 

 of the common mass, the supgrior face and the two anterior angles of the 

 ilium, the two sacro-iliac ligaments, and a small portion of the sacro-ischiatic 

 ligament. 2, On the trochanter (major) by its three posterior branches : 

 the first, or median, is a thick, round tendon fixed on the summit ; the 

 anterior is formed by a second wide, thin, and flat tendon, which is inserted 

 into the crest, .ifter gliding over the convexity ; the posterior is a small, 

 triangular, fleb^iy slip, aponeurotic at its anterior border, by means of which 

 it is attached behind the trochanter. This slip corresponds to the pyramidal 

 muscle of Man. 



Belations. — Covered by the gluteal aponeurosis and the superficial gluteal 

 muscle, it covers the ilio-spiBEalis, which receives its anterior point, the 

 iKac fossa, the small gluteal, the ilio-sacral, and sacro-ischiatic ligaments, the 

 sciatic nerves, and the gluteal nerves and vessels. Near the external angle 

 of the ilium it is bordered by the fascia lata and the iliacus, which are 

 closely united to it. 



Action. — When its fixed point is superior, this muscle extends and abducts 

 the thigh ; but when the femur is fixed, it causes the pelvis to rock on the 

 «. 



' We have been frequently able to convince ourselves that none of the fasciculi of 

 the superficial gluteus proceed direct from the iUuiu or the sacral spine. 



