358 TEE MUSCLES. 



tion, if at any time its position allows it to execute either of these two 

 movements. 



9. Gemelli (Fig. 197, 8, 8, 9). 



Synonyms. — Ischio - trochanterius — Girard. (Gemini — Percivall. Bifemoro - calcaneus — 

 Leyh.) 



The two small muscles which receive this name are far from presenting the 

 same arrangement in every subject ; but we will describe that which appears to 

 be the most frequent. Two little elongated muscular fasciculi are usually found, 

 one above, the other below, the tendon common to the two portions of the 

 obturator internus. These two fasciculi (Fig. 197, 8, 8), arise from the external 

 border of the ischiiun, follow the direction of the above-mentioned tendon, and 

 are inserted into it by the external extremities of their fibres, exactly representing 

 the gemeUi of Man. But there is also a third (Fig. 191, 9), wide, flat, and often 



Fig. 197. 



COCCYGEAL AND DEEP MUSCLES SURROUNDING THE COXO-FEMORAL ARTICULATION. 



1, Erector coccygeus ; 2, curvator coccygeus; 3, depressor coccygeus ; 4, compressor coccygeus; 5, 

 deep gluteus; 6, rectus parvus ; 7, tendon of the internal obturator; 8. 8, gemelli; 9, accessory 

 fasciculus of the gemelli; 10. quadratus femoris ; 11, sacro-sciatic ligament; 12, great sacro- 

 sciatic foramen ; 13, superior ilio-sacral ligament ; 14, inferior ilio-sacral ligament. 



very voluminous, situated between the preceding and the obturator externus ; it 

 is attached, by its inner border, to the external border of the ischium, contracting 

 intimate adhesions with the other two and with the tendon of the obturator 

 internus, and becoming inserted by the whole extent of its external border into 

 the trochanteric fossa. 



Relations. — Posteriorly, to the sciatic nerves ; anteriorly, to the capsule of 

 the hip-joint and the obturator externus, through the medium of an adipose 

 cushion. 



Action. — Like the preceding muscle, these rotate the thigh outwards, and 

 perhaps tend to produce its abduction. 



Differential Characters in the Muscles op the Thigh in the other Animals. 

 1. Anterior Crural Region. 



In the Ox, Sheep, and Goat, the iensor of the fa»cia lata is much wider than in Sclipeds ; 

 that of the Camel is so developed that it completely euvelo| s the triceps cruralis. In the 



